R&D Programs Facilities Staff · accurate characterization of x-ray mirrors used in synchrotron...

Brookhaven National Laboratory

R&D ProgramsFacilitiesStaff

Instrumentation Division

BNL 66826

BROOKHAVEN SCIENCE ASSOCIATES

INSTRUMENTATION DIVISION

R&D PROGRAMS

FACILITIES

STAFF

June 1999

http://www.inst.bnl.gov

This work was sponsored by the U.S. Department of Energy under Contract No. DE-AC02-98CH10886.

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United StatesGovernment nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees,makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness ofany information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Referenceherein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does notnecessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government of any agency,contractor, or subcontractor thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of theUnited States Government or any agency, contractor, or subcontractor thereof.

Contact Information: Building 535B

20 N. Technology Street

P.O. Box 5000

Upton, NY 11973

+1 516.344.4231

+1 516.344.5773 FAX

http://www.inst.bnl.gov

On the Cover:

1. Partially depleted 2-sided silicon strip detector, used for determining position of beam in the ATF.Signals from each of the 2 µm pitch strips are multiplexed via fan-out at lower right to anAMPLEX chip.

2. Long Trace Profiler, R&D 100 award winner and the most advanced instrument fornon-contact optical measurement of the surface figure and surface roughness onlarge aspheric mirrors, used for X-ray focusing in synchrotron beam lines.

3. Monolithic CMOS shaping amplifier. Micron, and now deep sub-micron,CMOS technology allow engineers to package many channels of electronicsinto a single chip, reducing cost and power consumption on very large scaledetector systems.

4. Silicon columns with submicron tip radii are produced by reactive ionetching, and may be used as field emitting devices in high brightnesselectron sources for new generation of accelerators at the ATF.

5. Mechanical drawing of 120° thermal neutron spectrometer for use inspallation source experiments. This state-of-the art detector usesultra-pure gases and advanced low noise electronics to yieldunsurpassed high rate, high resolution operation.

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CONTENTS

BRIEF OVERVIEW ............................................................................................................................... 2

OUR MISSION...................................................................................................................................... 3

FACILITIES........................................................................................................................................... 4

HISTORICAL PERSPECTIVE ............................................................................................................... 5

SCIENTIFIC AND PROFESSIONAL STAFF .......................................................................................... 6

AREAS OF ACTIVITY AND STAFF ..................................................................................................... 8

TECHNICAL SUPPORT STAFF ............................................................................................................ 9

CURRENT PROJECTS AND COLLABORATIONS .............................................................................. 10

PUBLICATIONS ................................................................................................................................... 11

FUTURE R&D DIRECTIONS ............................................................................................................ 12

DETECTOR DEVELOPMENT PROGRAMS ........................................................................................ 13

Gas Detectors ....................................................................................................................... 14

Cryogenic Detectors............................................................................................................ 18

Semiconductor Detectors ................................................................................................... 21

MICROELECTRONICS ........................................................................................................................ 25

PRINTED CIRCUIT BOARD DESIGN, FABRICATION AND ASSEMBLY ....................................... 30

DATA ACQUISITION AND CONTROL SYSTEMS .............................................................................. 33

MICROFABRICATION......................................................................................................................... 36

OPTICAL METROLOGY .................................................................................................................... 39

LASERS AND ELECTRO-OPTICS ...................................................................................................... 43

VACUUM DEPOSITION AND MATERIALS PROCESSING ................................................................ 48

SOLID STATE GAMMA-RAY IRRADIATION FACILITY .................................................................. 50

RADIO COMMUNICATIONS AND AUDIO SERVICES ....................................................................... 52

TECHNOLOGY TRANSFER ACTIVITIES .......................................................................................... 53

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BRIEF OVERVIEW

Mission: Develop state-of-the-art instrumentation for currentand future Laboratory programs

Established: 1948

Division Head: Veljko Radeka

Staff: 28 Scientific/Professional; 18 Technical; 4 Administrative

Research Areas: Detectors, signal processing, optics, microfabrication

Facilities: Clean rooms for semiconductor processing (Class 100)and detector fabrication

Laser and optics laboratoriesHybrid and integrated circuit design and testingMicrofabrication and electron microscopy laboratoryVacuum deposition laboratoryPrinted circuit fabricationIrradiation facility

Total Laboratory/Office Space: 35,000 sq. feet

Highlights of Accomplishments: Fast transistorized electronics for physics 1956experiments

First video game 1958Positron emission tomography 1960

(PET) detectorNeutron detectors 1973Liquid Argon Calorimeter 1973Synchrotron radiation detectors 1982Silicon drift detector 1983Long Trace Profiler 1987Monolithic low-noise circuits 1990Nanostructures 1994Deep sub-micron low-noise circuits 1999

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OUR MISSION

To develop state-of-the-art instrumentation required for experimental research programs at BNL,and to maintain the expertise and facilities in specialized high technology areas essential for thiswork. Development of facilities is motivated by present BNL research programs and anticipatedfuture directions of BNL research. The Division’s research efforts also have a significant impact onprograms throughout the world that rely on state-of-the-art radiation detectors and readoutelectronics.

Our staff scientists are encouraged to:

• Become involved in challenging problems in collaborations with other scientists.

• Offer unique expertise in solving problems.

• Develop new devices and instruments when not commercially available.

Scientists from other BNL Departments are encouraged to bring problems and ideas directly to theDivision staff members with the appropriate expertise. Division staff is encouraged to becomeinvolved with research problems in other Departments to advance the application of new ideas ininstrumentation. The Division Head integrates these efforts when they evolve into larger projects,within available staff and budget resources, and defines the priorities and direction with concurrenceof appropriate Laboratory program leaders. The Division Head also ensures that these efforts areaccompanied by strict adherence to all ES&H regulatory mandates and policies of the Laboratory.The responsibility for safety and environmental protection is integrated with supervision ofparticular facilities and conduct of operations.

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FACILITIES

FACILITY SPECIAL CAPABILITIES

Gas Detector Laboratory Clean rooms, fabrication and x-ray and particle testfacilities

Semiconductor Detector Laboratory Clean rooms, oxidation, mask alignment, wire bond-ing, detector characterization and testing, defectanalysis system

Hybrid Circuits Laboratory Low noise electronics prototype development

Monolithic Circuits Laboratory Design, simulation, testing

Computer-aided Circuit Layout Design of detector electrodes and multilayer circuitboards

Multilayer Printed Circuits Fabrication of detector electrodes and multilayercircuit boards using FR4/Polyimide/Teflon/glass andtetrafunctional materials

Optical Metrology Laboratory Digital optical surface profiler, Long Trace Profiler

Laser Laboratory Photoemission and fast switching studies; Ultrafastlaser applications

Microfabrication Laboratory Fabrication of microstructures, analytical electronmicroscopy

Vacuum Deposition Laboratory Coatings and multilayers

Solid State Irradiation Facility 60Co source. Radiation effects in insulators and semi-conductor materials and devices

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HISTORICAL PERSPECTIVE

The Instrumentation Division was founded in 1948, shortly after the Laboratory began operations,for the purpose of supplying detectors and fast electronics for high energy and nuclear physicsexperiments. The founders of the Laboratory recognized that specialized skills and facilities wouldbe needed to develop sophisticated detectors for the proposed experimental programs and establisheda dedicated facility for that purpose. With the development of increasingly complex detectors andelectronic systems, this rationale is as true today as it was 50 years ago.

As the major User Facilities of the Laboratory were built, the Instrumentation Division developeddetectors to study the particles and radiation that were produced. Gas, liquid, and semiconductordetectors for making precise measurements of position, time, and energy soon set the standard forthe state-of-the-art and have been emulated worldwide. The front-end electronics forms an integralpart of the detection system, and the Division devotes a high level of effort to co-developing optimalsignal processing, using the latest technology, for each detector that is built.

During the late 1970’s research in areas related to optics started in the Division. The need foraccurate characterization of x-ray mirrors used in synchrotron radiation beam lines resulted in theestablishment of the Optical Metrology laboratory. A Laser Laboratory was established to studyproblems related to the generation, acceleration, and detection of particles and for high speed dataacquisition and transmission. A capability to fabricate micro-machined structures has also beenadded, which complements our optics and microelectronics efforts.

Complementing our scientific expertise is a unique dual mode of conducting research. As aparticipant in a major experiment, an Instrumentation team builds a specialized detector along withits associated signal-processing electronics to create a highly-effective, customized instrument. It hasbeen through this mode of scientific collaboration that world-class experimental apparatus has beendeveloped here.

At the same time, through our generic research mission, the Instrumentation Division is free to studynew techniques that have no immediate application to any experimental program. In this way severalgroundbreaking developments have occurred. Examples are: the silicon drift detector, high-aspectratio micromachining techniques, the video game, ultrashort laser pulse characterization, andultralow-noise preamplifiers for low-capacitance detectors. More novel concepts, now in anembryonic stage of development within the Division, may one day serve as a foundation for entirelynew classes of instruments.

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W. Chen1 Designing and processing for position sensitive silicon detectors.

M. Citterio Signal processing and noise in physical measurements; electronics,physics and radiation effects on devices.

G. De Geronimo Low noise monolithic integrated circuits.

R.P. Di Nardo Electrical and optical coatings, detector fabrication, and specializedmaterials processing; training coordination & quality assurance.

J. Fried Experiment control and data acquisition system design.

J.A. Harder High speed electronics, monolithic circuits, analog and digital systemdesign.

A.T. Hrisoho2 Visiting Senior Scientist: signal processing and noise in physicalmeasurements; detectors and electronics.

A. Kandasamy Monolithic circuits, CAD, testing.

M.A. Kelley Data acquisition and experiment control systems software.

J.A. Kierstead Radiation effects in optical and semiconductor material and devices.

Z. Li Fabrication methodology for position sensitive silicon detectors; physicsof detector grade material; device physics and radiation hardness

D. Makowiecki Detector grade material; device physics; radiation hardness.

J.A. Mead Signal processing electronics and low background counting systems.

P. O’Connor Monolithic circuits, signal processing electronics, semiconductor devicephysics.

S. Qian Design and development of high-precision optical metrologyinstrumentation.

V. Radeka Signal processing and noise in physical measurements; detectors andelectronics.

S. Rankowitz Systems, electronics, and design automation.

SCIENTIFIC AND PROFESSIONAL STAFFAREAS OF INTEREST AND EXPERTISE

V. Radeka, Division Head28 Scientists and Professionals; 50 total including technical and administrative

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P. Rehak Physics of particle and radiation detectors; semiconductor detectors.

S. Rescia Signal processing and noise in physical measurements; detectors andelectronics.

N.A. Schaknowski Development of high resolution, gas-filled, radiation detectors and ultra-high vacuum systems.

J. Schill Development of high power, short pulse laser systems.

G.C. Smith Physics of and electronics for advanced ionization detectors; applicationsof such detectors to particle physics, solid state physics, and biology.

R.B. Squires Systems manager for computer network development and systemsmaintenance; CAD systems for monolithic design.

T. Srinivasan-Rao Short pulse, high power, IR, visible and UV lasers, laser drivenphotocathodes for electron gun and switching applications, electro-opticsampling and generation of coherent short pulse XUV, x-ray radiation.

F.W. Stubblefield Multiprocessor operating systems, high-speed data acquisition electronicsand computer interfaces, medical electronics for flow microfluorometry.

P.Z. Takacs Optical design and testing; figure and finish metrology of grazingincidence optical components; scattering of x-rays from smooth surfacesand its relation to surface topography.

T.Y.F. Tsang Ultrafast laser spectroscopy; high-intensity laser-matter interaction;surface-enhanced spectroscopy; nonlinear optics; fiber optics; opticaldetectors for high energy physics.

J.B. Warren Analytical electron microscopy, including SEM, EDX, microdiffraction,and computer simulation of crystal defect images, fabrication ofmicrostructures.

B. Yu Physics of and electronics for advanced ionization detectors; applicationsof such detectors to particle physics, solid state physics and biology.

D. Zhao RF and microwave circuits; monolithic circuit design

L. Zhao3 Position sensitive silicon detectors — fabrication and testing.

1 Physics Department2 Linear Accelerator Laboratory, Orsay, France3

STAR program, RHIC

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AREAS OF ACTIVITY AND STAFF

AREAS OF INTEREST

Detectors

Gas, liquid, and semiconductor particleand photon detectors;Detector physics and applications;Radiation damage in detectors

Signal Processing

Noise in physical measurements;Noise limits for various detectors;Electronics for position sensitive detectors

Optics and Laser Technology

Optical Metrology; Surface Roughness;Lasers and Electro-Optics;Microstructures;Coatings and Multilayers

Data Acquisition and Control

Multiprocessor Systems

High Technology Expertise

Electron Microscopy; Microstructures;Vacuum Deposition;Surface Profilometry, Interferometry andAtomic Force Microscopy;PC Design and Fabrication

1 Physics Department

2 Visiting Scientist

3 STAR program, RHIC

STAFF MEMBERS

W. Chen1, A. Hrisoho2, J. Kierstead, Z. Li,V. Radeka, P. Rehak, N. Schaknowski,G. Smith, B. Yu, L. Zhao3

M. Citterio, G. De Geronimo, J. Harder,A. Kandasamy, D. Makowiecki, J. Mead,P. O’Connor, V. Radeka, S. Rescia, D. Zhao

R. Di Nardo, J. Harder, S. Qian, J. Schill,T. Srinivasan-Rao, P. Takacs, T. Tsang,J. Warren

J. Fried, M.A. Kelley, S. Rankowitz,R. Squires, F. Stubblefield

R. Di Nardo, P. Takacs, J. Warren

TECHNICAL SUPPORT STAFF

Several technical support activities in the Instrumentation Division are essential to theScientific and Professional areas in the Division and to many other programs and activitiesthroughout the Laboratory.

Printed Circuit Board Design and Layout

Supervisor A. Kandasamy

Technical Advisor J.A. Mead

Technical Staff A.J. Della Penna, R.E. Machnowski, R.J. Ryan, K.J. Wolniewicz

Printed Circuit Board Fabrication

Supervisor M. Citterio

Lead Technician R.J. Angona

Technical Staff P.D. Borello

Electronics Technical Support

Supervisor M. Citterio

Technical Staff F.C. Densing, D.A. Pinelli, J. Triolo

Radio Communications and Audio Services

Supervisor S. Rankowitz

Lead Technician G.T. Walczyk

Technical Staff R.L. Dumont

Machine Shop

Supervisor R.H. Beuttenmuller

Technical Staff W.R. King, R.R. Ryder

Semiconductor Detector Fabrication

Supervisor Z. Li

Lead Technician R.H. Beuttenmuller

Technical Staff D.C. Elliott

Administrative Support

Supervisor C. Williams

Staff B. Gaer, D. Grabowski, J. McGowan, M. Riddick

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CURRENT PROJECTS & COLLABORATIONS

COLLABORATORS

Detector Development

X-ray Detector 1D & 2D, <100µm FWHM resolution

Biology; NSLS; Physics

High Resolution (<400µm FWHM) Neutron Detectors

Chemistry; Biology; LANL; NIST

Semiconductor Position Sensitive Detectors Milan Poly; CERN

Multi-element and Silicon Drift Detectors Wayne State

Radiation Damage CERN; Univ. Hamburg; Univ. Florence

Fast Noble Liquid Calorimetry. High Resolution EM Calorimeter with Liquid Krypton or Argon

Physics + 9 inst.; CERN; Columbia Univ. (Nevis Labs.)

Interpolating Pad Chambers for High Particle Multiplicities

Physics; CERN

Signal Processing

Hybrid and Monolithic Low Noise Amplifiers Penn; Milan Poly; Pavia; Symbol Technologies

Front End Electronics for Various Detectors LAL Orsay; Pavia; Penn; eV Products

Fast Noble Liquid Calorimetry Electronics Operated at Low Temperatures

Physics; LAL Orsay; CERN

Particle and Position Sensitive Detectors at the RHIC, HFBR, and NSLS

Biology; Chemistry; Physics; NSLS

Optics And Laser Technology

Optics Metrology and Properties of Optical Surfaces

NSLS; APS; LBL; Continental Optical Corp.

Lasers, Photocathodes, Fast Switching

Electro-optics and Ultrashort-Laser-Pulse Measurement Techniques

PROJECT

Data Acquisition Systems

Physics; ATF; SLAC; CERN; Brookhaven Technology Group

AGS; Physics; CPPM; Sandia; Montana State Univ.; Univ. of Pittsburgh

Microstructure Fabrication New Jersey Institute of Technology; Lockheed Martin

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PUBLICATIONS

Solutions to problems encountered in the development of state-of-the-art detectors and fastelectronics often involve investigations into the fundamental physical processes behind thesedevices. Instrumentation Division policy has always been to encourage staff members to publish theresults of these investigations and to actively participate in collaborations with other institutions. Theunique expertise and scientific contributions of Division staff have been recognized in the nationaland international scientific communities by numerous requests to participate in review panels andpresent invited talks at conferences and seminars throughout the world. The publication record ofInstrumentation Division staff over the 5 decades of our existence is shown in the following charts.*A milestone was reached early in 1999 when the total number of publications reached the 1000 mark.

The complete publication list for the Division can be found on its web site at the following worldwide web address: http://www.inst.bnl.gov/publications/publist.html

Requests for individual publications can be made directly to the Division office or through theResearch Library at Brookhaven National Laboratory.

* Data presented in the charts reflects only the first 6 months of 1999.

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FUTURE R&D DIRECTIONS

Instrumentation Division R&D efforts directly oriented toward future BNLfacilities and programs

RHIC New detector techniques for STAR and PHENIX

LHC ATLAS liquid argon calorimeter; low noise electronics for muondetectors

NSLS Energy-resolving x-ray detectors for high count rates; Position-sensitive silicon and gas detectors for x-ray scattering

HFBR Neutron detectors for low-angle scattering structural biologyexperiments

SNS Neutron detectors with time-of-flight capability

CAP/ATF High brightness electron sources

Muon Collider Detector techniques for very high backgrounds

Medical Imaging Special PET detectors

DAT collaborations Safeguards program — n,ÿg detectors; IAEA safeguards program;Remote detection

DAS collaborations Nano-particle analysis

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The program of the Division and the development of necessary facilities are motivated by present researchprograms and anticipated future directions of BNL programs. Thus a large part of our detector research anddevelopment is oriented toward the experimental programs at the AGS and RHIC. With the needs of futurehadron colliders in view, a program in detector development is being pursued in support of the BNL involvementin the ATLAS experiment at the LHC.

A significant part of the detector development program concerns x-ray and neutron scattering studies ofmolecular and crystal structures at the NSLS and the HFBR. A project is underway for building a large neutrondetector for protein crystallography in a collaboration with LANL.

There are three major areas of detector development in the Division:

• Gas Detectors

• Cryogenic Detectors

• Semiconductor Detectors

Each type of detector is optimized for detection of a particular type of radiation. Development and construc-tion of these detectors requires the specialized resources and facilities that are found in the various laboratories ofthe Division.

DETECTOR DEVELOPMENT PROGRAMS

� The Instrumentation Division is a leader in the development of thermal neutron detectors. The large size andinternal construction of a high-pressure multiwire proportional chamber used at the BNL HFBR is shown here.

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G. C. SmithB. YuP. RehakN. A. SchaknowskiE. F. Von Achen

The current work of the Group fulfills an importantpart of the Laboratory’s mission. Purpose-designed, some-times one-of-a-kind, radiation detectors are fabricated thatbecome part of forefront experiments performed at someof the major on-site facilities, in particular the NationalSynchrotron Light source (NSLS) and the High Flux BeamReactor (HFBR). A progressively increasing emphasis isbeing placed on detector development for the nation’s neu-tron spallation sources. Substantial support and consulta-tions are also provided to colleagues working on experimentsfor the Relativistic Heavy Ion Collider (RHIC).

Facilities and CapabilitiesThe gas detector development laboratory includes the

following tools:

• Stations for routine evaluation of devices• Test and measurement equipment• X-ray calibration facility• Neutron source (in Bldg 356)• Clean Room and laminar flow benches• Wire winding and lithography facilities• Material bake-out• Microscopes and inspection stages• Ultra-clean gas purification system

Gas Detectors

The Gas Detector Group began with pioneering developments in gas-filled spark cham-bers for high-energy physics in the 1960s. In the 1970s, with the advent of multiwire gasproportional chambers, the Group made important advances in the capabilities of thesedevices. In the 1980s and 90s, the Group has not only continued to make significantimprovements in gas detector performance, but has also been a leader in pursuing applica-tions of proportional chambers to fields in addition to high-energy physics, such as biol-ogy, materials science and chemistry.

We have a variety of computer-aided design tools forsimulation and design of detector configurations. A par-ticularly important capability is the visualization of electricfield lines and equipotentials for a wide range of detectorelectrode geometries.

� Transmission x-ray images ofa dime-sized plastic gear wheel,taken with position sensitivedetectors developed in thisdivision. Left hand pictureillustrates high resolutionperformance of early detectors,with residual non-linearity due toanode wire modulation. Righthand picture illustrates today’seven better performance, usingimproved designs, and representsone of the most accurate andlinear images ever recorded witha gas proportional detector.

To X-axis C

entroid Finding Elec

tronics

To Y-axis Centroid Finding Electronics

Cathode Wires

Anode Wires

CathodeStrips

Window

xy

n

p3H

3He

e

� Schematic diagram illustrating the principle of operation in allhigh performance imaging thermal neutron detectors developedat BNL.

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Synchrotron X-ray DetectorsKey characteristics of detector operation, such as posi-

tion resolution, position linearity, uniform illumination responseand count rate capability can be investigated with equipmentoutlined above, providing a unique, world-class, resource forgas detector development. For example, we have developedtechniques that have yielded the best position resolution evermeasured for X-rays in a gas based detector.

Emphasis is on detectors with high position resolution,high counting rate capability, and excellent efficiency. Ofparticular importance is the ability to perform dynamic studies.Our group has supplied to the NSLS detector systems thathave shed important light on activities as diverse as musclemovement and polymer behavior on time scales rangingdown to a millisecond. Our close interaction with usersprovides a timely understanding of their experimental re-quirements and enables us to produce state-of-the-art sys-tems that are unavailable commercially. Frequently, newgas detector concepts such as those with micropattern elec-trodes, are driven by high energy physics requirements,and we are well positioned to reapply those techniques inthe synchrotron environment.

The provision of detector systems for user facilities suchas the NSLS is carried out with support from the Division’sMicroelectronics Lab, Printed Circuit Design and FabricationLabs and Machine Shop. The Table shows listings of the group’sX-ray detectors in use and currently under development forvarious synchrotron experiments and of neutron detectors builtfor various neutron facilities in the U.S.

� Front cover of Synchrotron Radiation News (SRN). Taken atX12B of the NSLS with a 10×10cm2 detector, the picture shows afalse color encoded 2D diffraction image from a superimposedsample of dry collagen.

Thermal Neutron DetectorsHigh precision position sensitive thermal neutron de-

tectors are designed and built in support of Structural Biol-ogy and Chemistry research at BNL’s High Flux BeamReactor. Our current efforts in neutron detectors are in-creasingly focused on spallation source applications.

All detectors are 3He filled multiwire proportional cham-bers with interpolating cathode readout. They provide ex-cellent position resolution (typically 1–1.5mm FWHM).They also have high efficiency and counting rate capabil-ity, good timing resolution, low sensitivity to gamma ra-diation, no blooming effects and are particularly stable withrespect to recorded neutron position and dynamic range.

A variety of detector configurations have been imple-mented with sensitive areas ranging from 5cm × 5cm to50cm × 50cm, including detector arrays comprised of three20cm × 20cm detectors.

Existing detectors have proved to be reliable and in-valuable tools for researchers at BNL for over ten years.Measurements of position resolution performed with thesedetectors are unsurpassed by any gas detector group in theworld.

Other Gas DetectorsWe provide consultation to scientists, both from BNL

and the outside, who request assistance with existing andnew projects involving radiation detection solutions. Somedetector subsystems in RHIC and LHC (CERN) experi-ments utilize position encoding techniques developed inthis division. Two classic developments that epitomize this

� Picture of one corner of cathode/anode wire frame, part ofinternal electrode structure of advanced position sensitiveneutron detectors. Special techniques are developed to fabricatethese wire array, which typically contain hundreds of wires withdiameters < 50 µm. Chip resistors at edge of frame determineflow of electronic charge to preamplifiers and permit accurateposition measurement.

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are multi-element pad detectors (originally used in heavyion fixed target experiments at the AGS) and cathode stripchambers (CSCs), which were important systems in thedesign of SSC experiments, and are now critical elementsin the ATLAS experiment of LHC.

Another example of recent collaboration within BNLis the design and fabrication of a high pressure xenon ion-ization chamber for the Department of Advance Technol-ogy (DAT). As part of DAT’s National Security work withDOE, applications have arisen in which portable, low powerg-spectrometers, with energy resolution superior to cur-rently used field devices, are required. Compressed xenontechnology provides these characteristics, yielding 2% FWHMat 662 keV, a factor of 4 better than NaI.

The pursuit of basic R&D in gas detectors yields sig-nificant advances in performance. Two techniques inventedby our group that illustrate the benefit of supporting basicR&D are a method that significantly reduces parallax broad-ening for scattering experiments, and a method that signifi-cantly reduces anode wire modulation. Both of these haveproduced fundamental improvements in gas-based posi-tion-sensitive detectors.

Over the last few years the introduction of “micro-pattern” detectors by several top researchers around theworld has spawned a new generation of gas-based cham-bers fabricated by lithographic techniques. Already, at leastten generic patterns have been developed. Our group iscontributing to this exciting new development, primarily

� Internal elements of a high-pressure Xenon ionization chamberfor detecting gamma rays in an arms control and safeguardsapplication.

� Thermal neutron detector based on 3He and propane gasfilling. This device has a position resolution of less than 400µmFWHM, the best ever recorded for neutrons by a gas detector.This class of detector utilizes resistive charge division to achievehigh resolution performance. The open electronics at rear of thedetector shows hybrid preamplifiers (see Microelectronics) usedto measure the charge.

with the micro-pin array (MIPA). The Microfabrication sectionof this booklet illustrates some of the initial structures, andprovides an example of the interplay between sections ofthe Division.

ReferencesJ. Fischer, V. Radeka and G. C. Smith, “X-ray Position Detection in

the Region of 6µm RMS with Wire Proportional Chambers,”BNL 37948, Nucl. Instrum. & Meth. A252 (1986) 239.

B. Yu, G. C. Smith, V. Radeka and E. Mathieson, “Investigation ofChevron Pads for Position Encoding in Very High Rate, GasProportional Chambers,” BNL 44748, IEEE Trans. Nucl. Sci.38 (2) 454-460 (1991).

E. Mathieson and G. C. Smith, “Gain Reduction Due to SpaceCharge in a Multiwire Proportional Chamber Irradiated by aUniform Beam of Rectangular Section,” BNL 46620, Nucl.Instrum. & Meth. A-316 (1992) 246-251.

G. C. Smith and B. Yu, “The Linearity Performance of a Two-Dimensional, X-ray Proportional Chamber with 0.58 mmAnode Wire Spacing,” BNL 52423, IEEE Trans. Nucl. Sci.NS-42 (1995) 541-547.

P. Rehak, G. C. Smith and B. Yu, “A Method of Reduction ofParallax Broadening in Gas-Based Position SensitiveDetectors,” BNL 62980, IEEE Trans. Nucl. Sci. 44 (1997)651-655.

V. Radeka et al., “High Performance Imaging Neutron Detectors,”BNL 65032, Nucl. Instrum. & Meth. A419 (1998) 642-647.

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Beam Line Research Field Detector Characteristics

Gas Detectors Constructed for Specific Facilities

U4 NSLS Instrument and DiagnosticDevelopment

Low Pressure, Soft X-ray FluorescenceDetector

X1A NSLSUnder Development

X-ray Microscopy Multi-channel, Ultra-high RateSoft X-ray Detector, (~107 s-1)

X7A NSLS Powder Diffraction One-Dimensional Gas Detector10×1 cm2, ∆l/l =1/1000Rate: 5×105 s-1, Pressure: 4 atm.

One-Dimensional Gas Detector10×2 cm2, ∆l/l =1/1000Rate: 5×105 s-1, Pressure: 1 atm.One Dimensional, 100 channelGas Det. ∆l/l =1/100Rate: 108 s-1, Pressure: 1 atm.

X12B NSLS Time-Resolved and StaticX-ray diffraction ofMacromolecular Systems

Two-Dimensional Gas Detector10×10 cm2, ∆l/l =1/1000, 512×512Rate: 5×105 s-1, Pressure: 1 atm.

X21 NSLS Inelastic X-ray Scattering Two-Dimensional Gas Detector10×2cm2, ∆l/l =1/1000, 512×256Rate: 5×105 s-1, reduced anode modulation

X22 NSLS Surface Ordering at Liquid-Vapor Interfaces

One-Dimensional Gas Detector10×1 cm2, ∆l/l =1/1000Rate: 5×105 s-1, Pressure: 4 atm.

X25 NSLS Inelastic X-ray Scattering One-Dimensional Gas Detector10×1 cm2, ∆l/l =1/1000Rate: 5×105 s-1, Pressure: 4 atm.

X27 NSLSUnder Development

Powder Diffraction One-Dimensional, High Resn & RateGas Detector, curved for 120˚ coverage

SPEAR Stanford EXAFS Two-Dimensional Gas Detector10×2cm2, ∆l/l =1/1000, 512×256Rate: 5×105 s-1,reduced anode modulation

H3A HFBR Macromolecular NeutronCrystallography

Three 20×20 cm2 Detectors, 256×256 arraysResolution: 1.6 mm FWHMPressure: 9.5 atm

H3B HFBR Membrane NeutronSpectrometer

20×20 cm2 Detector, 256×256 arrayResolution: 1.6 mm FWHMPressure: 9.5 atm

20×20 cm2 Detector, 256×256 arrayResolution: 1.6 mm FWHMPressure: 9.5 atm

H5 HFBR Materials ChemistrySpectrometer

5×5 cm2 Detector, 512×512 arrayResolution: 300 µmPressure: 14.6 atm

H6 HFBR Chemical Crystallography Three 20×20 cm2 Detectors, 256×256 arraysResolution: 1.6 mm FWHMPressure: 9.5 atm

H9B HFBR Small Angle NeutronScattering Spectrometer

50×50 cm2 Detector, 256×256 arrayResolution: 2 mm FWHMPressure: 5.5 atm

Beam line14 LANSCELANLUnder Development

Protein & MembraneCrystallography

120˚ Curved Detector, 70cm rad. of curv.,17 cm heightResolution: 1.3 mm FWHMPressure: 9.5 atm.

In-house R&D

NIST Spin Echo Physics

20×20cm2 Detector, anode wire modulationstudy

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V. RadekaS. ResciaM. CitterioP. RehakD. Makowiecki

Noble Liquid Ionization CalorimetryRecently the cryogenic detector group, along with col-

leagues in the Physics Department, was charged with de-signing a very high rate calorimeter for the HELIOS NA34experiment at CERN. To overcome the limitations of thelong charge transfer time through the connection out of thecryogenic vessel, a cryogenic preamplifier was developedthat was able to work at the liquid argon temperature of-183°C. In the 1990s, liquid krypton detectors were devel-oped for high resolution calorimetry for the proposed Su-perconducting Super Collider (SSC). To date, the best energyresolution for a sampling calorimeter, 5.6/ÖE, was mea-sured on a test detector at CERN in 1994. With a negligibleconstant term, and with a 4.15GeV/ns timing resolution,This detector shows how good signal processing designcan extract a fast response from a detecting medium thathas a reputation for being “slow”. In the framework of theSSC activity, several types of cryogenic preamplifiers forhigh capacitance calorimeters have also been developed,including a monolithic version built on a radiation hard

Cryogenic Detectors

BNL is the birth place of the liquid argon calorimeter, pioneered by V. Radeka and W. J.Willis in 1973. Since that time this type of detector has been used in many high energy physics(HEP) experiments here and throughout the world. Some experiments utilizing the liquidargon calorimeter are E806, E807, L1, D0 and NA48. In the late 1980s, the cryogenic detectorgroup made important advances in the capabilities of these detectors and pioneered the fastcalorimetry readout techniques that opened the door for its use in the next-generation high-luminosity hadronic colliders.

JFET process developed ad hoc in collaboration with Interfet,Inc. for cryogenic applications. A discrete version, designedby the cryogenic group with Interfet components and engi-neered and built in Europe, equips the 13,000 channels ofthe NA48 liquid krypton calorimeter at CERN.

Detector R&DThe current activity of the cryogenic detector group is

mainly devoted to the liquid argon calorimeter for the AT-LAS detector at the Large Hadron Collider (LHC) cur-rently being built at CERN. This effort is in collaborationwith many institutions (Nevis Labs., University of Arizona,University of Pittsburgh, Stony Brook University, and BNL’sPhysics Department). BNL involvement includes many as-pects of the Barrel Calorimeter development: optimizationof detector design, electrode design, cold-to-warmfeedthroughs, calibration system, and readout electronics.R&D work on the components for which BNL is respon-

� The NA34 calorimeter before lowering into the cryogenicvessel, suspended from the vessel cover. The large white volumesare acrylic foam “fillers”. On the right side is the front section,connected to preamplifiers outside the vessel by the lowinductance flat cables (gold colored cables in the picture). To theright one can see the hadronic section and the cryogenicpreamplifiers, shown enlarged in the photograph below

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� Cross section of the proposedATLAS detector calorimeter. The fullcryostat of the Barrel Calorimeterwill be 6.8m long, with an outerradius of 2.25m. Inside the liquidargon vessel the calorimeter consistsof two half barrels, with a gap of fewmillimeters between. Each halfbarrel consists of 1024 lead-stainless steel converters withcopper-polyimide multilayer readoutboards in between. Connections aremade at the front and back face ofthe calorimeters usingmotherboards, which also house thecalibration resistive networks.Readout and calibration signals arerouted through cold-to-warmfeedthroughs to the electronicsenclosures housing the FEBs andauxiliary electronics (triggerbuilder, calibration, monitoring,slow control, etc.)

sible has been largely completed. The ATLAS barrel detec-tor requires 5 different types of summing boards and 14different motherboards with cryogenic high precision re-sistors (tolerance <0.1% at 90K). The cold-to-warm cable,the cable between the feedthroughs and the front endmotherboard (FEB) baseplane have been designed, and pro-totype quantities have been obtained. The FEB enclosure,a specially engineered crate capable of being mounted inany orientation (it will have to be mounted all around thecalorimeter), has been designed and prototyped, along withthe complex cooling system and the Faraday cage shield toprevent electromagnetic interference (EMI) to the sensitivepreamplifier input. BNL has participated in the 1998 CERNtest of a LAr prototype calorimeter aimed at testing newreadout hardware and feedthroughs to assess their perfor-mance with a barrell calorimeter electrode module. A sim-plified version of the FEB, comprising only the entire analogfront-end section and on-board calibration, has been suc-cessfully employed in this test.

Underway is the design of a radiation and neutronresistant, high efficiency, low noise switching power sup-ply to provide the low voltage, high current supplies of allATLAS calorimeters. Radiation and neutron resistance testsare under way to measure commercial switching powersupplies radiation resistance and to determine the feasibil-ity of retrofitting the modules with rad-hard components.

In the framework of the ATLAS activity, BNL has beena contributor in the design of the transmission line readoutof fast calorimeters, which is being employed by ATLAS.A new type of quad hybrid low noise, low power, high

dynamic range preamplifier has been designed for this pur-pose. Underway are reliability studies to discover possiblefailure modes of the electronics and to assess the meantime between failure (MTBF). Activity is ramping up forthe manufacturing and testing of the larger quantities neededfor the “Module 0” test in 1999 and for the full productionrun: in excess of 50,000 hybrids, for a grand total of morethan 200,000 channels, are needed for ATLAS. A fully com-puter-controlled automated test station, which will allowfull traceability of each preamplifier, is being set up for thispurpose.

In a collaboration with the University of Arizona, thecryogenic group has designed the connection of the AT-LAS forward calorimeter to the front-end preamplifier viaa wide-bandwidth transmission line transformer designedfor cryogenic operation in a magnetic field. The use ofsuch a transformer allows formation of the tower connec-tion of four cells inside the cryogenic vessel, thus reducingthe number of cables penetrating the cryostat.

Facilities and CapabilitiesThe art of cryogenic detectors involves knowhow from

many different disciplines, ranging from vacuum techniques,materials science, contamination control, cryogenics to mod-eling of detectors components and readout electronics. Thegroup has a proven track record of design, fabrication, in-stallation and operation of noble liquid calorimeters at BNLand at outside facilities. We rely on a suite of techniquesdeveloped over the years to model detector parameters. We

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can measure and monitor liquid purity and properties intest cells. Readout electrodes are modelled as equivalentcircuits either analytically or with the help of circuit simu-lation programs (HSPICE, PSPICE). Instrumentation Divi-sion electronic measurement instruments are invaluable tomeasure the characteristics and electrical properties of de-tector components as they are built, both to validate thedesign and for quality assurance. Actual construction relieson the support of the Printed Circuit Board Design facili-ties and the machine shop. Readout electronics are designedand built in the Division’s Hybrid and MicroelectronicsLab. Over the years we have developed a close link withmany vendors of specialized services, ranging from largeprinted circuit board manufacturing (as long as 2m), toprecision silk screening over large areas, to multilayer flexiblecircuits which allow us to reliably contract out fabricationwork too large to be handled in-house.

Detector for a Muon-Muon ColliderQuite recently, there has been a considerable effort to

assess the feasibility of constructing a muon-muon collider.One of several problems is a large particle background,due to decaying muons, which arrives at the detector si-multaneously with those particles of interest from the µ+µ-

interaction. The radiation dose near the intersection can behigh enough to exclude silicon as a vertex detection mate-rial. A possible alternative to silicon is a liquid argon-basedstrip and/or pixel detector. Although liquid argon has lower

electron mobility than silicon, this is not a problem for amuon-muon collider, where interactions (and also back-ground) are at least 2µs apart. A preliminary study indi-cates that 10µm position resolution is attainable with existingreadout electronics.

ReferencesW. J. Willis and V. Radeka, “Liquid Argon Ionization Chambers

as Total Absorption Detectors,” Nucl. Instrum. & Meth.120, (1974) 221-236.

V. Radeka and S. Rescia, “Speed and Noise Limits in IonizationChamber Calorimeters,” BNL 40397, Nucl. Instrum. &Meth. A265 (1988) 228-242.

O. Benary, “Performance of an Accordion ElectromagneticCalorimeter with Liquid Krypton and Argon,” Nucl.Instrum. & Meth. A344 (1994) 363-377.

O. Benary et al., “Precision Timing with Liquid IonizationCalorimeters,” Nucl. Instrum. & Meth. A332 (1993) 78-84.

R. L. Chase et al., “Transmission Line Connections BetweenDetector and Front End Electronics in Liquid ArgonCalorimetry,” Nucl. Instrum. & Meth. A330 (1993) 228-242.

R. L. Chase and S. Rescia, “A Linear Low Power RemotePreamplifier for the ATLAS Liquid Argon EM Calorim-eter,” IEEE Trans. Nucl. Sci. Vol. 44, No. 3, June (1997)1028-1033.

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Detector R&DSemiconductor materials have been used for detecting

radiation for almost as long as the transistor has been in-vented. About 15 years ago, three new kinds of semicon-ductor detectors were proposed:

• Drift detector

• Fully depleted charge couple device (CCD)

• Low capacitance drift photodiode and X-ray detector

The invention of these new detectors took place in theInstrumentation Division of BNL, where most of the analysiswas done. The first detectors were produced at LBNL andat MPI Munich. Recently, several experiments at CERNand at BNL have used, or are presently using, silicon driftdetectors to measure the position of fast charged particlespassing through the detector. Experiments planned at RHICand LHC are building large vertex detectors based on sili-con drift detectors. These detectors are the direct result ofdevelopment work done in this Division. The usefulnessof these detectors has extended into other areas of sci-ence. Presently, silicon X-ray drift detectors are com-mercially available for microanalysis in electronmicroscopes. A fully depleted CCD is ready to be launchedin 1999 as a main focal plane detector for the Multi-Mirror X-ray (MMR) satellite mission.

Semiconductor Detectors

Z. LiP. RehakR. BeuttenmullerW. ChenL. Zhao

� Silicon drift detector for STAR

Semiconductor charged particle detectors first became important to nuclear physics researchin the early 1960s. Brookhaven’s Instrumentation Division was one of the first groups to study,develop and produce these devices in the USA and continues as a leader in this area to this day.In 1964 lithium-drifted germanium detectors were introduced, and BNL promptly began toproduce high quality gamma-ray spectrometers using these devices. These in-house produceddevices allowed BNL nuclear physics to excel in the field of gamma ray spectroscopy. Devel-opment continued at BNL with these detectors as the material of choice changed from lithium-drifted to high purity germanium. Along with the production of high-resolution devices, BNLalso made early and significant contributions to the understanding of radiation damage effectsin germanium, starting in 1967 and continuing through 1979. In the early 1980s planar manu-facturing technology was introduced to silicon detector fabrication, coinciding with interestfrom high energy physics in high precision, position-sensitive charged particle detectors. Acleanroom was established at BNL and IC fabrication methods were introduced, yieldingdetectors first for the CERN NA34 experiment in 1985. We have since designed and produceda wide variety of silicon detectors (pad, micro-strip, drift, and pixel detectors) with applicationsin HEP, X-ray spectroscopy, and nuclear physics at BNL, CERN, FNAL, LANL and otherinstitutes. Studies on radiation effect in silicon have continued along with the detector develop-ment work, for which BNL remains one of the leading groups in the world.

Semiconductor ProcessingThe Instrumentation Division’s Semiconductor Detec-

tor Development and Processing Lab (SDDPL) has beenthe main R&D center for development and production ofprototype solid-state radiation and particle detectors (RPD)for various nuclear and high energy physics experiments atBNL and other sites (e.g. CERN) around the world. Its

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state-of-the-art design and processing facility for RPD isunique in the United States among university, industrial,and other national laboratory facilities, and is one of only avery few that exists elsewhere in the world. Our capabili-ties encompass the complete detector production process,which includes simulation of processing and device elec-trical behavior, detector and mask design, all the necessarydetector processing steps (from oxidation to photolithogra-phy to metallization) except for ion implantation (performedby an outside service with a turnaround time of 2-3 days),and detector testing and characterization.

Facilities and ToolsSimulation Tools

The processing simulation tool allows one to go throughthe entire detector processing even before a single wafer ishandled. This step provides understanding of the physicsof detector processing, helping to identify and eliminatepotential problems before the actual processing. Key fea-tures of the simulation tool include doping profiles of vari-ous ion implants.

The device simulation tool allows one to check detec-tor behavior under working biases before processing andtesting. This step provides the understanding of detectorphysics under working conditions and prevents potentialfailures of detectors before they are processed. Key fea-tures of the simulation tool include profiles of electric po-tential, electric field, and carrier concentrations.

Fabrication Facilities

A new Class-100 cleanroom has been in use since June1996. The 600 sq. ft. room includes fully-instrumented wetbenches, hot deionized water, better ventilated photoresistspinner, larger gowning area with pass-through, megasoniccleaning, automatic photoresist coating track, double-sidephotolithography mask aligner, two-target sputtering sys-

� A 3-D plot simulation of the electric potential distribution, in asilicon drift detector for STAR at RHIC

� Double-sided mask aligner station in the Class 100 cleanroomfacility.

Drift Direction [µm] Depth [µm]

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tem, exterior furnace installation, and a large capacity ni-trogen boil-off system. Conditions inside the room, withconstant temperature and humidity, are monitored by a centralcontrol unit. Verification of Class-100, or better, operationhas been achieved. Supporting systems include laser wafercutter and automated wire bonder.

After fabrication, detectors are tested using our testingand analytical facilities:

• Standard probe station for I-V, C-V tests on test diodes

• Probe-card testing facility for STAR drift detectors

• Defect analysis systems: I-DLTS, TSC, and TCT,with laser lights for carrier generation (mainly usedfor identification and analysis of processing-relateddefects and irradiation-induced defects.

Radiation Damage Effect HardnessStudies

Silicon radiation detectors continue to be applied tonuclear and high-energy physics experiments in both in-creasing complexity and quantity. Detector radiation hard-ness against displacement damage has become a major issuein the development of silicon tracking detectors for high-energy physics experiments at the LHC.

We have been studying the effects of fast neutron andionizing particle radiation on the electrical properties ofsilicon radiation detectors, which are in widespread use asposition sensitive detectors in high energy physics experi-ments. These damage effects will be especially important inhigh luminosity experiments such as at the LHC. Deep LevelTransient Spectroscopy (DLTS), current shape, Thermally

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ReferencesZ. Li and H. W. Kraner, “Gettering in High Resistive Float Zone

Silicon Wafers for Silicon Detector Applications,” BNL41347, IEEE Trans. Nucl. Sci. NS-37 (1), 290-292,February (1989).

W. Chen et al., “Large Area Cylindrical Silicon Drift Detector,”BNL 45022, IEEE Trans. Nucl. Sci. NS-39, 619 (1992).

Z. Li, “Investigation on the Long-term Radiation Hardness ofLow Resistivity Starting Silicon Materials for SiliconDetectors in High Energy Physics,” BNL 60155, Nucl.Instrum. & Meth. A360 445 (1995).

Z. Li, “Experimental Comparisons Among Various Models forthe Reverse Annealing of the Effective Concentration ofIonized Space Charges (Neff) of Neutron Irradiated SiliconDetectors,” BNL 60274, IEEE Trans. Nucl. Sci. NS-42, No.4, August (1995) 224.

Z. Li et al., “Study of the Long Term Stability of the EffectiveConcentration of Ionized Space Charges (Neff) of NeutronIrradiated Silicon Detectors Fabricated by Various ThermalOxidations,” BNL 60294, IEEE Trans. Nucl. Sci. NS-42,No. 4, August (1995) 219.

B. Schmidt et al. “Relaxation of Radiation Damage in SiliconPlanar Detectors,” BNL 62149, J. Appl. Phys. 76(7), 1October (1994) 4072-4076.

Z. Li et al., “Simulation and Design of Various Configurationsof Silicon Detectors for High Irradiation Tolerance Up to6×1014 n/cm2 in LHC Application,” BNL 64488, pres. 7thPisa Meeting on Advanced Detectors, Elba, Italy, 25-31May (1997), sub. Nucl. Instrum. & Meth. (in press).

R. Bellwied et al., “Anode Region Design and FocusingProperties of STAR Silicon Drift Detectors,” BNL 65288,Nucl. Instrum. & Meth. A400 (1997) 279-286.

Stimulated Current (TSC) measurements, and Transient Cur-rent Technique (TCT) reveal specific defect structures inthe silicon lattice that cause increased thermally-generatedcurrent (dark current), space charge transformations (or “in-version”), and short and long term annealing effects. Inter-action of defects with benign, endogenous impurities in thesilicon material used in these detectors offer possible ame-lioration of the effects of bulk displacement defects and weare pursuing methods of enhancement of these impurities(e.g., O, Sn, C, N).

The defect analysis system (DLTS, TSC, and TCT),including optical defect filling techniques, has been com-pleted and is in routine use. The “reverse anneal” effect wascorrelated with a deep acceptor at Ec-0.4 eV, which is usu-ally attributed to the di-vacancy. High carbon content mate-rial was found to exhibit annealing and radiation effectproperties not very different from normal material. Positronannihilation studies have been applied to neutron-irradiatedsilicon for the first time and an indication of clusters (voids),which break up during anneal and supply vacancies, hasbeen observed. Measurements on oxygenated silicon detec-tors using BNL’s oxygen diffusion technology (developedin 1992) have shown improved rad-hardness to radiation ofcharged particles (protons, pions, etc.) of a factor of 3 fromstandard materials. We are the first group to use low resis-tivity silicon materials for particle detectors with improvedradiation hardness, which is a leading candidate of the ac-tual material for detector fabrication in LHC applications.

Continued measurements of material-engineered sampleswill be made to establish electronic effects of specific struc-tures (di-vacancy, etc.). Further studies will continue indefect engineering, using samples such as Sn-doped FZsilicon wafers to fabricate radiation hardened detectors.We are a major contributor in a R&D collaboration (RD48,the ROSE collaboration) devoted specifically to the devel-opment of radiation-hard silicon detectors for both ATLASand CMS at the LHC.

� Silicon Vertex Tracker drift detectormodules for the STAR Project are wire-bonded to each other (center) and toHybrid Amplifiers (sides) on theAutomatic Wire Bonder machine. TheBonder is capable of placing 2 bonds persecond, but is normally operated at halfthat rate. Each module requires over2,400 individual bonds to be made. All216 modules will require about 531,000total bonds, which will take almost 20working days to complete.

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Semiconductor Detector Applications

Detector Application Results/Status 400 element pad detector, ceramic overlay;three sets of charge-divided strips

NA 34 (CERN) Used in exp. for three yearsBeuttenmuller et al.,NIM A252 (1986) 471

512 element pad detectors, large and smallinterior holes

E814 (AGS, BNL) Used for several years as multiplicity counterGiubelino, et al., NIM

192 element pad detectorssquare array

TRD test Used at CERN for several years (V. Polychronakos)

192 element pad detectorscircular array

NA 44 (CERN) Used at CERN for several years (V. Polychronakos)

3 in diameter cylindrical silicon driftdetectors

NA 45 (CERN) First drift detector applicationChen et al., IEEE TNS NS39, 619(1992), NIMA326 (1993)

STAR 6.3×6.3 cm2 silicon drift detectors SVT for STAR at RHIC Prototype detectors for 216 detector SVT arrayfinishedNow in production at BNL and SINTEF (on-going)

50 micron pitch strip detectors Muon Beam Finder(CERN)

In use for two years in M2 test beam (V. Polychronakos)

2 and 8 micron pitch strip detectors Accel. Test Facility,BNL

Production used PdSi methodZ. Li et al., IEEE TNS NS38 (1991)

50 micron pitch strip detectors Current AGS To be installedL. Remsberg, V. Polychronakos

PHOBOS test detectors PHOBOS at RHIC Polyimide coating test, FOXFET structuresRyan, Busza, MIT

120 element array high-rate EXAFSdetectors

NSLS X19 Successful tests with 16 elementsPullia et al., NIM, BNL-62142, 62735(on-going)

16 element strip for diffraction NSLS Siddons, to be installed

Radiation effects test diodegamma ray irradiation

BNL gamma source Kraner et al., Italian Phys. Soc., Vol. 46, Baldinied., Bologna (1994)

Radiation effects test diodeDisplacement damage effects

Fast neutrons Z. Li et al., numerous publicationsStill on-going

p-type pixel detectors (n+/p/p+)48µm×192µm pixels120×8 array96µm×96µm pixels16×60 array

Prototype for CMS atLHC

Lander, UC DavisUnder test, on-goingZ. Li et al., BNL-64488, to appear in NIM

n-type pixel detectors (n+/n/p+)125µm×125 µm pixels24×32 array250µm×62.5µm pixels12×64 array

Prototypes for CMS atLHC

Chien, Johns Hopkins Univ.Under test, on-goingZ. Li et al., BNL-64488, to appear in NIMW. Chen et al., BNL-64979

n-type pixel detectors (p+/n/n+)200µm×200µm pixels24×32 array

Fermilab D0 Anderson, Kwan, FermilabUnder test, on-goingZ. Li et al., BNL-64488, to appear in NIMW. Chen et al., BNL-64979

100 µm pitch large-area strip detectors37 cm2 sensitive area, AC coupled withimplanted biasing resistors

Prototype for PP2PP atRHIC

Guryn, PhysicsTo be tested at FermilabOn-going

Drift detector array for high–rate EXAFS NSLS X19 Siddons, NSLS, to be tested, On-going

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CapabilitiesThe Microelectronics Group specializes in the design

and prototyping of analog and digital circuits in CMOS,bipolar, and hybrid technologies, including their interfac-ing to detectors and data acquisition systems. Relying on athorough understanding of the user’s experiment, we pro-vide compact, low noise packaging of ASICs together withcommercial parts on a PCB or hybrid circuit for a completesignal processing solution. Specific abilities include:

• Full custom, transistor-level design, mask layoutincluding extraction and verification of criticalanalog blocks;

• Accurate SPICE simulation including componentnoise characterization and modeling done in-house;

• Access to state-of-the-art semiconductor processingincluding submicron CMOS, BiCMOS, and high-speed bipolar, incorporating precision passivecomponents for analog design;

• Digital standard cell libraries and compatible synthe-sis tools;

• In-house PCB and hybrid shops for high-densitypackaging and rapid prototyping;

• Cost estimation (ASIC and PCB);

• Fully equipped test laboratories for device character-ization through system level testing.

Facilities• Full suite of ASIC design tools including:

Design capture:Viewlogic PowerviewOrcad CaptureTanner Tools S-Edit

MICROELECTRONICS

P. O’ ConnorG. De GeronimoM. CitterioA. KandasamyP. RehakR. MachnowskiS. ResciaJ. A. MeadD. ZhaoD. PinelliJ. A. HarderF. Densing

From the outset, one of the Instrumentation Division’s main roles has been to providecustom-designed electronics for a wide range of research programs. In particular, low-noisecircuits for processing the signals from sensitive radiation detectors have been an area of focusfor almost 50 years, and BNL has established a worldwide reputation as a leader in this field.More recently, we have been seeking to apply some of the sweeping developments in micro-electronic technology to provide high performance electronic systems for experiments requir-ing either (1) extreme compactness, (2) very high quantity (>1000) of identical units, or (3)special electrical characteristics unavailable in conventional, commercial devices.

Starting in the 1990s, an increased emphasis has been placed on monolithic techniques.Despite the overwhelming advantages of silicon VLSI for digital circuits, it poses manyconstraints for low noise, high precision signal processing work. The Microelectronics Groupconducts research on circuit design to provide solutions to these problems.

� CMOS Preamp Shaper monolithic circuit chip for PHENIXTime-Expansion Chamber. Actual size 3.3 mm×4.9 mm.

Circuit simulation:Avant HSPICEOrcad PSPICE

Full custom layout:MAGICCadence IC CraftsmanTanner Tools L-EDIT

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Layout extraction and verification:MAGICTanner Tools LVS

PCB and hybrid layout:PADS PowerPCBAUTOCAD

• Foundry arrangements with:

Hewlett-Packard (MOSIS):0.5 µm, 0.35 µm and 0.25 µm CMOS

Peregrine (MOSIS):0.5 µm CMOS SOS

Orbit Semiconductor:0.8 µm and 0.5 µm CMOS

Maxim:bipolar

AMS (Europractice):1.2 and 0.8 µm CMOS and BiCMOS

Harris:1.2 and 0.8 µm bulk radiation-hardenedCMOS

Matra MHS1.2 µm radiation-hardened SOI CMOS andBiCMOS (DMILL)

IBM0.35 µm CMOS

• Two test laboratories: full suite of test equipmentincluding analytical prober, semiconductor devicecharacterization with noise measurement, time- andfrequency-domain test equipment up to 5 GHz.

� Triple preamplifier card, developed for use in a wide range ofradiation detectors. Components are fabricated on a 0.025 inchthick alumina substrate. Special transistor packages, chipcapacitors, and thick film resistors are used. Finished product isencapsulated in very high resistivity clear coating, primarily toinhibit moisture. (Winner of IR-100 award).

• PCB fabrication facility: recently upgraded, canproduce up to 24 layer boards on a variety of sub-strates with a minimum line width down to 1 mil; linespacing down to 2 mils, holes down to 4 mils, fullsurface-mount assembly capability.

• Hybrid circuit prototyping: alumina, beryllia, orfiberglass substrates, automatic and manual wirebonders, encapsulation, inspection, test, and rework.

• Access to other Division laboratories, includinganalytical electron microscopy, vacuum depositionlaboratory, and solid state irradiation facility (20 kCi60Co source.)

Current Research Areas• Low-noise charge-sensitive amplifiers. This is a broadarea encompassing circuits for gas, liquid, and solid detec-tors; detector capacitances ranging from 10-14 to 10-8 F; andwork on circuits which must operate in cryogenic or heavyradiation environments.

• Device characterization. Noise properties of FETs invarious technologies; cryogenic and radiation effects; de-vice and parasitic modeling for circuit simulation.

• Other signal-processing subcircuits. Flash ADC,switched-capacitor waveform memory, calibration and tim-ing circuits.

• Hybrid microcircuit technology. Pushing the state of theart in density and complexity by working with new materi-als and techniques.

• Wireless RF communications. Miniaturized spread-spec-trum radio operating in the 2.5 GHz ISM band.

� Monolithic CMOS shaping amplifier, approximate size100 µm × 200 µm, showing layout of passive components. Theresistor is a serpentine of polysilicon, resistivity 22W persquare, line width 2 µm. Capacitor (pink square) at top ofserpentine is formed by sandwiching a SiO

2 layer between two

polysilicon plates.

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ProjectsHigh Energy and Nuclear Physics

Front end electronics for PHENIX and STAR at RHICand for ATLAS at the LHC. During 1998, we producedmore than 50,000 channels of FEE ASICs and boardsfor PHENIX and more than 100,000 channels of ASICsand hybrids for STAR. We have committed to delivermore than 60,000 channels of FEE for ATLAS.

X-ray Detection

A CMOS charge-sensitive preamplifier coupled to asilicon drift detector (both designed at BNL) recentlyachieved the best energy resolution for X-rays of anyMOS-based amplifier. We are now studying extensionof this concept to use scintillators coupled to silicondrift detectors with CMOS preamps for imaging usinghigher energy X-rays of interest in medicine. We havebegun work on a CRADA with eV Products to developsingle and multichannel preamp/shaper/driver for usewith CdZnTe solid-state high X- and g-ray detectors.These will be used in medical and industrial imagingand inspection.

CRADA with eV Products, Div. of II-VI, Inc.

Development of Multi-Channel ASICs for CdZnTeGamma Ray Detectors

Award date: March, 1997Duration: 3 years

Our project objective is to aid the commercializa-tion of CdZnTe (CZT) multiple element demonstratedfeasibility and produce quantities of these arrays for po-tential industrial and medical applications. A viable com-mercial product must have the associated electronics inASIC (Application Specific Integrated Circuit) formatin order to assemble large areas of detector arrays or to

� 241Am spectrum measured with CMOS preamplifier and silicondrift detector. The equivalent input noise charge at -70ºC is 13rms. electrons, the best noise ever measured in a MOS-basedcharge-sensitive amplifier.

� Miniaturization achieved by monolithic circuit is shown in thispicture. At bottom is a single preamplifier in hybrid technology,while at top is a fast shaping amplifier in the same technology.The small monolithic circuit in the center contains eightpreamplifier/shaper channels, with virtually the same noise andlinearity characteristics as the hybrid components. About a2000:1 area savings is realized.

make small and disposable single channel systems. Theelectronics must be compatible with the CZT detectorcharacteristics and, at a minimum, preamplify and shapethe pulse signals from the detector elements. There cur-rently exist a large need for solid state gamma and X-rayimaging capability for both medical and industrial ap-plications. In industry, a need exists for imaging foodproducts for foreign matter, non-contact, high speed weigh-ing of consumer products to insure minimum weight com-pliance and multi-energy high speed imaging ofmanufactured products to detect subtle defects. Solidstate CZT arrays offer the possibility of reducing theweight and bulkiness of existing nuclear medicine cam-eras based on NaI scintillators and photomultiplier An-ger camera technology. Small, hand held, imaging devicesshow promise for locating cancer tissue during surgerythrough the use of monoclonal antibodies tagged withradioactive tracers. For security screening, CZT arrays,when used with multi-energy X-rays, can detect explo-sives and other contraband.

Technical Approach:

1. Evaluate the performance of various existing BNLASICs with CZT arrays.

2. Adapt the existing design or study novel configura-tions so that the ASIC performances matches theCZT detectors requirements.

3. Develop, produce and test ASIC prototypes for CZTapplications.

Wireless Communication

With Symbol Technologies, we are exploring thedevelopment of a single-chip, wireless transceiver oper-ating in the newly opened 2.4 – 2.5 GHz ISM band. This

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low-power “radio-on-a-chip” will be used in short-range,mobile data communication links in such environmentsas warehouses and retail. There may be applications inlarge HEP experiments as well.

CRADA with Symbol Technologies

Microcircuits and Sensors for Portable, Low-Power DataCollection and Transmission

Award date: May, 1997 Duration: 3 years

Our project objective is to design, fabricate and testtwo novel devices for data collection and transmission:an optical photosensor array and a 2.4 GHz, single-chip,frequency-agile radio transceiver. Both devices can beprocessed in a standard CMOS integrated circuit pro-cess. CMOS technology has advanced to the point wheremany conventional electronics systems can be fully in-tegrated on a single chip. Up to now, the vast majority ofthese chips perform purely electronic functions. In thisCRADA, we propose to investigate two integrated cir-cuits with sensors which can process information in theform of radio-frequency waves and optical images.

Technical Approach:

1. Wireless Transceiver

Our project goal is to develop an inexpensive, single-chip, frequency agile, RF transceiver operating at the2.4GHz range — a universally accepted unlicensed band.We have demonstrated successful circuit blocks in ourexisting small CRADA. In the new CRADA, we pro-pose to use a higher performance CMOS 0.35 micronprocess to achieve lower power consumption and higherintegration density.

2. Imaging Detector

For the optoelectronic imaging portion of the CRADA,we will investigate the “active pixel” architecture. Thisarchitecture uses photodiode sensors which can be made ina native CMOS process. The imaging array requirements(pixel size and count, spectral responsivity, speed, signal-to-noise ratio, dynamic range, linearity, crosstalk, and powerconsumption) will first be specified based on a knowledgeof the 2D bar code reader system. We plan to model alter-native photodetectors using the semiconductor device simu-lation codes currently used at BNL for silicon radiationdetector development.

ReferencesP. O’Connor, “Low Noise CMOS Signal Processing IC for

Interpolating Cathode Strip Chambers,” BNL 61085, IEEETrans. Nuc. Sci. NS-42, No. 4, August (1995) 824-829.

G. Gramegna et al., “CMOS Preamplifier for Low-CapacitanceDetectors,” BNL 64026, Nucl. Instrum. & Meth. A390(1997) 241-250.

G. Gramegna et al., “Low-Noise CMOS Preamplifier-Shaper forSilicon Drift Detectors,” BNL 64028, IEEE Trans. Nucl.Sci. 44(3) (1997) 385-388.

P. O’Connor et al., “CMOS Preamplifier with High Linearityand Ultra Low Noise for X-ray Spectroscopy,” BNL 64027,IEEE Trans. Nucl. Sci. 44(3) (1997) 318-325.

P. O’Connor et al., “Ultra Low Noise CMOS preamplifier-shaper for X-ray spectroscopy,” Nucl. Instrum. & Meth.A409 (1998) 315-321.

G. De Geronimo and P. O’Connor, “A CMOS Detector LeakageCurrent Self-Adaptable Continuous Reset System: Theoreti-cal Analysis,” BNL 65574; Nucl. Instrum. & Meth. A421(1999) 322-333.

� 240-channel hybrid readout circuit for the STAR Silicon Vertex Detector at RHIC. This 6×2 cm2 circuit contains 30custom ICs which interface to the anodes of a silicon drift detector on 250 µm pitch. Preamplifiers, shaping amplifiers,and analog buffer memory are provided on this hybrid circuit.

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ASICs Developed by the Microelectronics Group

Chip Project Function Technology Designers

IC31 PHENIXTEC

Preamp/Shaper CMOS 1.2 µm P. O’Connor, A. Kandasamy

IC34 ATLASCSC

Preamp/Shaper/Discriminator/ Track-and- Hold

CMOS 1.2 µm P. O’Connor, A. Kandasamy

IC35 STAR SVT Preamp/Shaper CMOS 1.2 µm P. O’Connor, S. Hart

IC37 STAR SVT Preamp/Shaper CMOS 1.2 µm P. O’Connor, S. Hart

M531A STAR SVT Preamp/Shaper Bipolar D. DiMassimo

PHX-FADC

PHENIXTEC

Flash ADC CMOS 1.2 µm J. Harder

IC38 Xray/SDD Preamp CMOS 1.2 µm G. Gramegna, P. O’Connor

IC1-AMS

Xray/SDD Preamp CMOS 1.2 µm G. Gramegna, P. O’Connor

IC40 Wireless Frequency synthesizedTransmitter

CMOS 0.5 µm H. Vu, T. Vu, A.Kandasamy, W. Miller

IC43 CRADA eV Preamp/Shaper/Driver CMOS 1.2 µm G. De Geronimo

IC44 CRADASymbol

Direct-conversionreceiver

CMOS 0.5 µm H. Vu, T. Vu, A. Kandasamy

IC45 CRADA eV Preamp/Shaper/Driver:Unipolar Shaping

CMOS 0.5 µm G. De Geronimo

IC46 CRADA eV Preamp/Shaper/Driver:Unipolar Shaping BLR


IC47 CRADASymbol

LNA CMOS 0.5 µm D. Zhao

IC48 CRADA eV Preamp/Shaper/Driver:Bipolar Shaping


IC49 CRADA eV MultichannelPreamp/Shaper/Driver


�

DesignThe PCB design group has personnel, software, and

equipment geared towards fabricating and assembling thecircuit boards.

Capabilities

• Schematic entry

• Place and Route.

Manual place and route.Automatic place and route.

PRINTED CIRCUIT BOARD DESIGN,FABRICATION AND ASSEMBLY

� Photo-plotter in the darkroom being loaded with a26”×20” photographic film for transferring theimages from the workstations to the film using a lowpower laser beam.

As the “brains” of sophisticated electronic devices used in experiments throughout theLaboratory, specialized circuit boards are required. These Printed Circuits Boards (PCBs)are exposed to such extreme environments as high radiation, humidity, and cryogenictemperatures in a wide variety of experiments. Circuit boards for these diverse applica-tions are not readily available commercially. Our facility is capable of designing, fabricat-ing and assembling unique PCBs for Instrumentation Division research activities and forother Laboratory programs and activities requiring such specialized circuit boards.

Recent expansion and upgrading of this facility with state-of-the-art equipment hasmade it an invaluable resource to the Division, for BNL’s scientific community, and forour international collaborators.

The Division’s PCB design, fabrication and assembly personnel possess the skills andexpertise required for realizing many different types of boards. The fabrication facilitycan prepare multilayer circuit boards with drilled holes of unprecedented accuracy and,with the equipment available, conducting circuit lines in the boards can be made muchthinner, and the spacing much closer, than those on commercially mass-produced boards.

R.J. AngonaP.D. BorelloM. CitterioA.J. Della PennaF.C. DensingA. KandasamyR.E. MachnowskiJ.A. MeadD.A. PinelliR.J. RyanJ. TrioloK. Wolniewicz

• Data translation for artwork generation.

• Generation of data for CNC drilling of boards.

• Photo-plotting (artwork) capabilities.

Software

• PADS PowerLogic - Schematic entry

• Viewlogic ViewDraw - Schematic entry

• PADS PowerPCB - Place and Route

• Cadence Specctra - Automatic place and route engine.

• AutoCAD - Computer Aided Drafting

• CAM 350 - Artwork generator and analysis.

• HyperLynx - Signal Integrity analysis.

Equipment

• Cymbolic Sciences F9650 LASER Plotter.

• Optronics L2620 LASER Plotter.

• Kodamatic 66s Photo Processing Unit.

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FabricationThe printed circuit board fabrication group produces

custom circuit boards from the engineer’s initial design tothe finished board, with the capability to produce featuressuch as fine holes for via structures and components, ultrafine width and pitch conductive circuit traces. The facilityalso has the capability to fabricate boards using a widerange of materials like Kapton, Teflon, etc. The facility hasan optical inspection station in its process line, which isused for inspecting individual layers for defects such asunder or over etched traces, shorts, or opens in traces.

The facility has been and is actively involved in pro-ducing prototypes for various experiments for Brookhavenexperiments and collaborations. Some of the experimentsfor which the facility has provided its services are:

• RHIC experiments at Brookhaven.RHIC Beam instrumentation.PHENIX.STAR.

• AGS facility at Brookhaven.

• LHC experiments at CERN.ATLASNA45

The fabrication facility offers a wide range of servicesfor the scientific community using environmentally safetechniques and equipment, complying with all local, stateand federal regulations.

� Automatic Optical Inspection (AOI) system in operation fordetecting faults in circuit board layers.

Capabilities

• Multilayer printed circuit boards.

• Rigid-Flex boards.

• Optical inspection of individual layers.

• Computer controlled machinery (drilling, routing) forhigh precision and repeatability.

• Liquid Photo Imageable (LPI) solder masks.

Equipment

• Dynamotion DM31- Numerically controlled drillingmachine capable of hole sizes up to 4±1 mils;programmable Z-axis; drill rate of 200 hits/minute.

• Western Magnum Laminator.

• Optibeam and OLEC AP-300 exposure units capableof transferring ultra-fine width and pitch traces to thematerial using its highly collimated light source.

• Developer and Etcher with pump speed control tovary spray pressure for varying line weight; LPIsolder mask and legends.

• Camtek 2V20 - Automatic optical inspection station.

• Accudyne - Vacuum-assisted computer-controlledhydraulic laminating press.

• Dynamotion/ATI CNC router.

• Precision oven with temperature range from ambientto 550°F, with fully programmable cycles forpreparing the boards for assembly.

AssemblyThe circuit board assembly group in Instrumentation

is a cost-effective means of assembling specialized customcircuit boards or for performing any kind of rework on

� Seen above is a circular circuit board made for the siliconvertex telescope at the NA45 experiment at CERN. The boardhouses 24 monolithic circuits that amplifies the signals from thesilicon detector mounted in the center of the board.

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existing fixtures or off-the-shelf electronics. The personnelclosely integrated into the web of the electronics group inInstrumentation are skilled in the art of assembling elec-tronic components into the circuit boards fabricated eitherat the facility or elsewhere. The boards prepared by thisgroup then make their way into an experiment or onto anengineer’s test bench. The group utilizes a wide range ofequipment for assembling large or very small componentsto silicon die as small as 2 mm × 2 mm with as many as 40input/output pads in them.

� Assembled multilayer printed circuit board is being inspectedafter the components have been soldered to the board using thesurface mount reflow oven.

Capabilities

• Through hole and surface mount component assem-bly (QFP’s, BGA etc.).

• Wire bonding for monolithic components.

• Chip on board assembly.

• Custom test fixtures and panel assembly.

Equipment

• OK Industries SMT 8001 - Manual pick and placemachine for surface mount component assembly.

• OK Industries KEM 410 - Infra-Red reflow oven forsoldering surface mount components.

• Novastar 2000A Convection reflow oven used forsoldering large size circuit boards and BGA assem-blies.

• Pace TF500 - Circuit board rework station.

• K&S 4123 - Manual aluminum wedge bonder.

• K&S 4124 - Manual gold ball bonder.

• Palomar 2470 - Automated wedge bonding machinewith pattern recognition capabilities.

• Dage 4000 - Die and Ball shearing machine and wirepull tester.

• MARCH Plasmod - Plasma cleaner for die cleaning.

• Asymtek C700 - Automatic fluid dispensing systemfor die encapsulation for chip on board circuits.

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The Instrumentation Division has produced 4 gen-erations of neutron and x-ray spectrometer data acquisi-tion systems for experiments at the HFBR from itsinception in 1965 to the present.

In the late 1950s, real time computer installations ininstrumentation and laboratory automation became fea-sible for the first time. In the nuclear instrumentationfield, the interest was mainly associated with multipa-rameter, multichannel data acquisition and analysis. De-velopments in the computer industry quickly transformedthe issue of how to use computers to what was the mostappropriate computer system architecture for the par-

DATA ACQUISITION AND CONTROL SYSTEMS

S. RankowitzJ. FriedJ.F. GannonM.A. KelleyJ.A. MeadR.B. SquiresF.W. Stubblefield

� Beam position monitor for RHIC

Since the MERLIN computer was built in the 1950s to collect and analyze data in HighEnergy Physics experiments, the Instrumentation Division has been active in advancing thetechnology of data acquisition and experiment control for the major scientific research pro-grams at the Laboratory and throughout the world. The Instrumentation Division has provideddetector and computer control systems for a wide range of DOE-sponsored programs, such asat the Cosmotron and the AGS for High Energy and Nuclear Physics; at the High Flux BeamReactor (HFBR) and the National Synchrotron Light Source (NSLS) for Basic Energy Sciencesand for Molecular Structures for Life Sciences. The Division has played a pioneering role inmany other smaller research programs, from pioneering Positron Emission Tomography (PET)data acquisition in the 1960s to the development of FASTRUN, a high performance computingdevice for molecular mechanics using a pipeline architecture with a power of 500 millionfloating point operations per second, used to calculate the forces and energy produced by pair-wise interactions of many objects in a system for a Life Sciences program in the 1980s.

ticular laboratory environment. Various approaches wereproposed for multi-user systems. Dedicated architecturessupposedly could be used independently of other people’splans, experiments and laboratories. However, the highcost of peripherals and large memories made such sys-tems prohibitively expensive. The higher level languagesin operating systems were geared towards more generalconfigurations rather than dedicated applications. Con-sequently, early support developed for general purposemulti-user centralized architectures, where all resourceswere pooled within one structure with the idea of gain-ing economy and performance by sharing, with someloss of independence flexibility.

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In 1965, the Instrumentation Division pioneered thedevelopment of a multiple spectrometer control system(MSCS) to simultaneously operate, control and monitorone x-ray spectrometer and 8 neutron spectrometers atthe new Brookhaven HFBR. This system provided bothtime-shared multi-experiment control and real-time datareduction. The spectrometers were used by independentresearch groups and, consequently, had to be individu-ally controllable. The typical spectrometer had 5 motor-driven axes, 2 detectors, limit and error switches,incremental axis angle encoders, beam intensity monitorcounters, ovens, dewars, etc., which all needed to bemonitored. All control stations were identical and inter-changeable, and provided the direct interactions famil-iar to users of manual controllers. These stations couldbe operated under local or computer control (ScientificData Systems SDS 920), where the computer was cen-trally available to the individual experimenters. All semi-and fully-automatic operations were handled from thecomputer console. Data recording and display for all theexperiments were centered in this room.

A centralized computer control was selected for theHFBR system because any individual spectrometer con-troller had to include a general computational facility.The complexity of the experiments planned for the newReactor required that settings for a measurement may bebased on the results of a previous measurement. If indi-vidual controllers were to be used, they would have tobe small, economical, general-purpose digital comput-ers. Memory size and peripherals requirements wouldvary with the complexity of the control computations.The most economical approach for the system was tocentralize all the computational power and timeshare itsuse among the individual spectrometers.

In the early 1970s, smaller and more powerful com-puters, introduced by Digital Equipment Corp. (PDP-11), made possible the development of a Multi-User RealTime Computer Network with functional distribution sys-tem architecture. A computer network for real-time dataacquisition, monitoring, and control of a series of ex-periments at the Brookhaven HFBR was developed andplaced in routine operation to replace the centrally con-trolled multiple spectrometer control system. The ninespectrometers, and several additional experiment con-nections, were controlled by the new Reactor Experi-ment Control Facility (RECF).

The PDP-11 computer was unique at the time as aresult of its UNIBUS structure, i.e., a well documented,published backplane signal and timing specification. Itwas in widespread use, enabling industrial companiesand users to provide compatible modules, components,subassemblies, and interfaces. It became the most uni-versal de facto standard available to all. Many of thecomponents for spectrometer control and monitoring werebuilt as printed circuit cards to be plugged directly intothe UNIBUS backplane for interfacing directly to the

processor. Third party vendors competed to provide newsemiconductor memories to replace the prevailing mag-netic core memory technology of that period.

In the late 1970s, an important system componentwas added to the multiprocessor node UNIBUS archi-tecture: a random access memory resource where large,common data arrays of up to several million words andcommon control parameters were stored and could beaccessed by several functional processor nodes. It pro-vided the basis of several large scale and some smallersystems, most important of which were (1) a system formonitoring and managing animal inhalation chambersand restricted access rooms for experimental data acqui-sition and data analysis at the new Inhalation Toxicol-ogy Research Facility, and (2) a data acquisition andcontrol system for a spectrometer with a 20 x 20 cmposition-sensitive detector used in neutron scattering ex-periments at the Brookhaven HFBR.

In the late 1970s to early 1980s, continuing rapiddecreases in the cost per function of microprocessorsand functional large scale integration circuits included anew set of microprocessor products by Digital Equip-ment Corp., e.g., the LSI-11 microprocessor, based on aQ-BUS backplane and consequent 3rd party compatiblehardware and software products. The instruction set andmany of the structural features were compatible with theearlier PDP-11 minicomputers. Node components wereinterconnected via the Q-BUS (node BUS). A node con-sisted of one LSI-11 processor, one serial diagnostic chan-nel for independent testing of the node, a random accessmemory and a terminator module with support hard-ware, such as time out circuits, real time clock, time-of-day clock, node start-up program and node identificationin read-only memory. Up to 8 functionally-compatible nodescould form a cluster. Each node in the cluster was con-nected via an access port to a common random accessmemory resource of 67 million bytes.

� Generic ARCNET board used for intelligent general purposecontrol in the high magnetic field environment of PHENIX.

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A long distance inter-cluster communication link wasdesigned with one node in each cluster, dedicated tooperate the communication protocol with a program storedin read-only memory. The functional independence inthis system allowed coupling of functionally incompat-ible or unrelated clusters.

In the early 1980s, the RECF at the HFBR was re-placed with such a system at all the active spectrom-eters. For Molecular Structure Biology x-ray and neutronspectrometers, an advanced time-resolving data collec-tion system was implemented and placed in routine op-eration. Data from multiple high resolution positionsensitive area detectors, with a maximum cumulativerate of 300,000 events per second, were collected. Theevents were sorted, in real time, into many time slicearrays. A programmable timing control unit provided awide choice of time sequences and time-slice array sizes.

In 1987, the Instrumentation Division DAQ groupadopted the new VME standard and designed and builtthe first VMEbus system based on the Motorola 68020microprocessor, a Time-Sliced Data Acquisition Systemfor Area Position Sensitive Detectors with secondary DMAcapability to other CPUs, such as a Digital EquipmentCorp. Microvax. Time slicing data acquisition systemswere built in the early 1990s and are now in use at theNSLS and HFBR, at small angle spectrometer stations,as well as at the neutron protein crystallography station.The modular nature of the system is such that the hard-ware and the primary software for these different appli-cations are nearly identical, while the secondarydata-processing software is specifically tailored to theparticular application.

Since 1993, the Data Acquisition and Control Sys-tems Group has been almost entirely devoted to activi-ties related to RHIC and one of its major experiments,PHENIX (Pioneering High Energy Nuclear Ion Experi-ment). The importance of RHIC to the Nuclear Physicsprogram and to the Laboratory as a whole requires anintensely focussed effort in areas where the Laboratoryhas direct responsibility, such as data acquisition for theRHIC beam instrumentation system, certain subsystemsof PHENIX, e.g., the Time Expansion Chamber (TEC)tracking system front-end electronics; timing system;ARCNET control and monitoring communications net-work; and programmable pulse generator for experimentsystem testing.

� Prototype Time Expansion Chamber Front End Modules (TECFEM) for PHENIX. Two 64 channel modules are shown installedin a crate. Over 200 of these modules will be required

ReferencesRHIC Beam Position Monitor System

J.A. Mead and T.J. Shea, “A DSP-based Data AcquisitionModule for Colliding Beam Accelerators,” 6TH Int’lConference on Signal Processing Applications andTechnology, Boston, 24-26 Oct. 1995.

T.J. Shea, J.A. Mead and C.M Degen, “DSP-based DataAcquisition for RHIC,” Proc. 1995 Particle AcceleratorConference, Dallas, May 1995.

T.J. Shea et al., “Evaluation of IEEE 1394 Serial Bus forDistributed Data Acquisition, ” Proc. 1997 ParticleAccelerator Conference, Vancouver, B.C., May 1997

PHENIX

“Timing System Electronics,” RealTime99 Conference, SantaFe, 14-18 June 1999.

“Time Expansion Chamber Front End Electronics,” RealTime99Conference, Santa Fe, 14-18 June 1999.

“ArcNet Control Network,” RealTime99 Conference, Santa Fe,14-18 June 1999.

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FacilitiesThe Microfabrication Laboratory is fully equipped

with the hardware and software necessary for completemicrofabrication design, processing, and characterization.Visiting investigators are encouraged to actively partici-pate in the design process by learning the fundamentalmicrofabrication processes, such as anisotropic etching,plasma etching, and high aspect ratio lithography, and bydesigning mask sets for the chosen method. Patterningsteps take place in a Class-100 clean room equipped withresist spinners, developing tanks, and etching stations. AKarl Suss MJB-3 mask aligner, with both vacuum andhard contact modes, is used for UV exposure, and a Nikonoptical microscope, equipped with a custom-designed quan-titative metrology measurement capability, is used foranalysis. An adjoining Class-1000 room contains oxida-tion furnaces for growing oxide layers on silicon wafers,a wet bench for anisotropic etching, and Plasmalab reac-

J. B. WarrenD. C. Elliott

MICROFABRICATION

Microfabrication of commercial products and scientific instrumentation based on MEMS, orMicro Electro Mechanical Systems, is now a worldwide activity. Derived from the batch-processed methods of the integrated circuit industry, current MEMS products include inertialsensors for automotive airbags, inkjet printer heads for printers used in the personal computermarket, and biomedical sensors for DNA hybridization analysis. The versatility of MEMSfabrication methods has generated increasing interest in the capabilities of the InstrumentationDivision in this area. A number of applications involving integrated sensors and specializedmicrostructures for use in BNL’s multi-user facilities, such as the NSLS, RHIC, and the ATF, arealready under active development. The goal of the Microfabrication Laboratory is to respond tothe specific needs of the BNL scientific community by fabricating microstructural componentsrequired for experimental apparatus, and to interact with local industries and academic institu-tions in joint ventures that enhance the MEMS manufacturing knowledge base.

tive ion etching and plasma-enhanced chemical vapor depo-sition chambers. Completed microstructures can be exam-ined with a high resolution AMRAY scanning electronmicroscope equipped with a LaB6 gun, and a PrincetonGamma Tech image and X-ray analysis system.

Current ProjectsThe Microfabrication Laboratory was formed in 1989

to assist the newly formed Accelerator Test Facility in thefabrication of microstructure arrays used to study novelacceleration mechanisms with a laser linac. The expertisegained in this area has since been used to manufacturespecialized microstructures for many investigators in bothacademia and industry. Ongoing projects include infraredfilter arrays for NASA, high resolution masks for e-beamdeposition for Brandeis University, and industrial collabo-rations with Lockheed-Martin and Standard Microsystemsto develop multi-axis accelerometers and improved ver-

sions of ink jet printer heads using high as-pect ratio microfabrication

In the Lockheed-Martin CRADA, a vari-ant of high aspect ratio microfabrication (com-monly known as the LIGA process) has beenused to form the critical component of a mi-cro-accelerometer with three translation andthree rotational sensing axes. The deviceworks by levitating a cubical proof mass with

� CRADA with Lockheed Martin TacticalDefense Systems to develop a micro-accelerometer with 3 translation and 3 rotationalmeasurement axes. The prototype uses highaspect ratio electroplated copper coils to levitatepermanent magnets attached to a cubical proofmass.

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permanent magnets mounted on each face of the cube.Microfabricated copper levitation coils oppose the field ofeach magnet and provide a restoration force that keeps theproof mass centered in the sensing enclosure. Levitationcoil current levels are monitored to determine the actualacceleration component for each axis. With the multi-Gaccelerations commonly encountered in aerospace applica-tions, high current levels in the coils lead to thermal dissi-pation restrictions that can only be circumvented by lowerresistance coils. These low resistance coils can be fabri-cated in a given space only by increasing the aspect ratio ofthe coil cross-section, a procedure that can only be achievedby high aspect ratio microfabrication.

High aspect ratio lithography is also being used topattern a freestanding membrane used as a deposition maskfor electron beam evaporation. Here, coded openings, witha dimension of 2 to 3 µm are patterned in an array of highaspect ratio resist and then placed in close contact with anickel foil in preparation for vacuum metallization. Sincethe foil is only a few thousand Angstroms thick, it cannotbe patterned directly using normal methods. Chromium isdeposited through the membrane openings to form a pat-tern on the foil that is irradiated with positrons and thenreexamined with a high-resolution transmission microscopefor crystal defects induced by the positron interactions.This technique is being developed by Prof. Karl Canter ofBrandeis University and BNL’s Physics Department, usingpositron sources located at BNL and LLNL.

Other applications require freestanding metal mem-branes. For this case, the metal is electroplated around highaspect ratio resist. After electroplating, the resist is dis-solved and a frame is bonded to the electroplated metalfilm. Patterned films measuring several square inches inextent have been formed in this manner. As shown in themicrograph, freestanding nickel filter arrays fabricated inthis manner have been used as infrared filters that selec-

� High speed x-ray detector array for synchrotron applications

tively pass a narrow band of the infrared spectrum. Criticaldimensions of the individual pattern holes are on the orderof 2-3 µm. The bandpass spectrum depends critically onthe hole pattern, pitch, and film thickness. Prof. Dieter Moellerof the New Jersey Institute of Technology and Dr. JimHeaney of NASA’s Goddard Space Flight Center have beeninvolved in this effort.

High aspect ratio microfabrication with SU-8 photore-sist is being used to fabricate two-dimensional position-sensitive detector arrays that have the potential to greatlyincrease the data collection rates of X-ray diffraction ex-periments at the NSLS and other synchrotrons. The SU-8resist can be patterned with traditional UV lithography, yetdisplay micostructural aspect ratios that heretofore wereonly achievable using X-ray lithography with a synchro-tron. SU-8 is an epoxy-based resist and is sufficiently rug-ged to be integrated into the microstructure of the detector.The micrograph shows a detector array where both theanode and cathode are composed of vacuum-metallizedSU-8. Anode and cathode portions of the array are formedby sequential patterning steps of both the anode and cath-ode portions of the array. The anode is composed of acylinder 200 µm high and 50 µm in diameter that is en-closed by the hexagonal cathode that is 400 µm high

Significant Accomplishments• Developed High Aspect Ratio Silicon Grating for Use

in Laser Acceleration experiments at the AcceleratorTest Facility (1989)

• Developed several methodologies for the Fabricationof Patterned Thin film Membranes for IR Spectrom-eters and Positron Re-emission Spectroscopy. (1992-1995)

• CRADA with Lockheed Martin Tactical DefenseSystems of Archbald, PA for the Development ofMulti-Axis Accelerometer using Advanced Micro-fabrication Methods (approved 1995)

� Freestanding thin metal membrane Infrared filters forinterferometry in the 10-20 µm range

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• Developed Rapid Prototyping method for the in-house design and fabrication of microstructures(1996)

• CRADA with Standard Microsystems of Hauppauge,LI, NY for the Development of High Aspect RatioResist in Ink Jet Printer Head Fabrication (approved1998)

• Developed method using multilayer metallized SU-8resist to form position sensitive X-ray detector arrayfor synchrotron X-ray diffraction applications (1998)

ReferencesJ. B. Warren, “Control of Silicon Field Emitter Shape with

Isotropically Etched Oxide Masks,” 2nd Int’l Conf. OnVacuum Microelectronics, Bath, England, 24-26 July(1989), Inst. Of physics Conf. Ser. 99, Sect. 2, p. 37-40.

W. Chen et al., “Proposal for a Study of Laser Acceleration ofElectrons Using Micrograting Structures at ATF (Phase I),”BNL 43465, Center for Accelerator Physics, 28 October(1989).

J. T. Rogers, J. B. Warren and A. Gray, “Microstrip BeamProfile Monitor,” Workshop on Advanced Beam Instrumen-tation, KEK, Tsukuba, Japan, 22-24 April (1991), KEKProceedings, June (19910 p. 91-91.

J. B. Warren, “Characterization for Micromechanics Using DeepEtch Lithography,” Active Materials and AdaptiveStructures, p. 407-410, (1992) Gareth J. Knowles, ed., Inst.of Physics, Philadelphia.

J. B. Warren, J. B. Heaney and K. D. Moeller, “Filters andWavefront Diving Beamsplitters for the Near and MidInfrared Produced by Micromachining Techniques,” 18thInt’l Conf. on Infrared and Millimeter Waves, Sept. 1993,Colchester, U.K., Conf. Digest of 18 Int’l Conf. 2104, p.357-358, J. R. Birch & T. J. Parker, eds.

K. D. Moeller et al., “Cross Shaped Bandpass Filters for theNear- and Mid-Infrared Regions,” Applied Optics, 35, No.31, 1 Nov. 1996, p. 6210-6215.

� High Aspect Ratio Deposition Mask

�

Major Activities• Provide metrology services to users and manufactur-

ers of synchrotron optics.

• Provide feedback to manufacturers to enable processimprovement.

• Develop and maintain the capability to measuresurface roughness and figure error on large optics.

• Maintain specialized instrumentation and expertisefor performing optical testing, installation, andalignment of synchrotron optics.

• Develop new test methods, techniques, and instru-mentation.

• Maintain a stock of standard optical laboratorycomponents and equipment available on loan to BNLstaff and guest workers for experiment breadboard-ing.

• Provide guidance and expertisein the selection, specification,and fabrication of opticalcomponents.

• Study the properties of surfaceroughness and how it affectsimage quality in grazing- andnormal-incidence x-ray optics.

OPTICAL METROLOGY

P. Z. TakacsS. Qian Located within the Instrumentation Division, the Optical Metrology Laboratory (OML) at

Brookhaven National Laboratory is actively involved in improving the quality of opticalcomponents used in synchrotron radiation (SR) beam lines throughout the world. Establishedin 1983, the OML has developed instrumentation and measurement techniques that are criticalto the successful performance of high-precision aspheric optics, such as those found in beamlines at the National Synchrotron Light Source. The instrument technology that has beendeveloped in the OML has been successfully transferred to a local small business under theauspices of a CRADA initiated in 1993.

Current ProjectsThe resources of the Optical Metrology Laboratory

are available to the SR community for testing componentsto be used in beam line systems. We average between 50and 100 separate items each year that are logged in forroughness and figure error testing. Our specialized facili-ties and laboratory space are available to NSLS users andother laboratory groups for installation and alignment ofcomponents in monochromator systems and for breadboard-ing of special tests and experiments. We continue to pro-vide expertise in solving optical design and testing problemsfor the entire Laboratory. Major projects in which we havebeen involved are as follows:

• Developing an In Situ Long Trace Profiler (ISLTP)instrument through a CRADA program with Conti-nental Optical Corporation in collaboration with the

� Pictured with the R&D 100 Award-winning LTP II are the majorcollaborators (clockwise from left):Steve Irick, LBL, Eugene Church andPeter Takacs, BNL, and ManfredGrindel, President of ContinentalOptical. Not available for this photo isShinan Qian.

�

Advanced Photon Source at Argonne NationalLaboratory.

• Assisting Continental Optical Corporation in devel-oping a Vertical Scan LTP (VSLTP) for measuringcomplete x-ray telescope mirrors and mandrels for aPhase II SBIR project sponsored by NASA MarshallSpace Flight Center.

• Investigating damage to mirrors caused by long-termexposure to synchrotron x-rays.

• Developing models for predicting the performance ofx-ray optics based on measurements of surface figureand finish parameters. This work is being donethrough a long-standing collaboration with Dr. E.L.Church, who has extensive expertise in signalprocessing theory.

• Developing standard artifacts and test methods forcalibrating surface profiling instruments.

• Investigating the absolute curvature of nearly-flatspherical optics to be used in the Laser Interferomet-ric Gravitational Observatory (LIGO) project, incollaboration with NIST and the California Instituteof Technology.

Rationale for a Metrology LaboratoryIn the early part of the 1980s, during the construction

phase of the first NSLS beam lines, it became apparent thatconventional optical fabrication and testing techniques wereinadequate to meet the needs of the synchrotron radiationcommunity. Mirrors needed for grazing incidence beamlines were often shaped like segments of cylinders or tor-oids, or far off-axis conic sections: paraboloids and ellip-soids. These mirrors proved extremely difficult tomanufacture, since they required unconventional grindingand polishing techniques, and no suitable metrology tech-niques existed for testing the quality of these surfaces.

Recognizing the need to develop optical metrologyinstrumentation and techniques tailored specifically to grazingincidence optics, the Instrumentation Division establisheda program in 1983 to investigate surface roughness andfigure errors in high performance optics. The core of theprogram was funded through internal overhead funds, withadditional funding through an FWP which was initiated inFY’85 through the Materials Science Division of BasicEnergy Sciences at DoE.

Surface Finish MetrologyDuring the late ’70s and early ’80s when the National

Synchrotron Light Source was in its final construction phase,the major concern was to get mirrors made with sufficientsmoothness to minimize scattered light and preserve theintrinsic source brightness. The unconventional design ofgrazing incidence optical systems required the use of faroff-axis aspheric mirrors — cylinders, toroids, ellipsoidsand paraboloids — that were extremely difficult to manu-facture and polish to a smooth finish. One of the primaryreasons why it was so difficult to manufacture grazing inci-dence aspheres was the lack of suitable metrology instru-mentation that could accommodate full-size meter-long optics.To insure that mirrors and optical systems would be able tomeet the stringent requirements imposed by the synchro-tron beam, the Optical Metrology Laboratory was estab-lished in 1983 in the Instrumentation Division.

Fortunately, at about this time, a commercial surfaceprofiling instrument was developed that revolutionized surfaceroughness measurement technology. The micro phase-mea-suring interferometer (micro PMI) enabled quick and accu-rate measurement of surface roughness with sub-Ångstromlevel accuracy on parts of any size or shape. We acquired aWYKO NCP-1000 Digital Optical Profiler and began pro-viding manufacturers with feedback that allowed them toimprove the quality of the surfaces provided to us. Since

we were pushing micro PMI technology be-yond the limits of its intended use, we estab-lished a research effort, in collaboration withE.L. Church, to understand the performanceof the instrument and to validate the link be-tween surface roughness measurements and theactual performance of a mirror in a SR beamline. This has been, and continues to be, a veryfruitful collaboration.

Using signal processing techniques, weanalyzed the instrument performance in thespatial frequency domain and developed soft-

� Current implementation of the surfaceroughness profiler in the OML. Custommodifications allow it to measure Ångstrom-level roughness on full-sized SR mirrors quicklyand easily.

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ware to compute the power spectral density (PSD) functionof the measured roughness profiles. We developed meth-ods for characterizing the transfer function of the micro-scope-based profiler and for correcting the measured profilesfor high-frequency roll-off in the imaging system. Our ef-forts at understanding the performance of this new type ofsurface profiler eliminated the error sources that plaguedthe intercomparison of roughness measurements made withdifferent techniques and permitted accurate prediction ofscattered light intensities from x-ray mirrors. Our method-ology for using the PSD function to describe surface roughnesshas been incorporated into an ISO standard and is in theprocess of being added to ASTM and ANSI standards.

As a service to the SR community, we provided mea-surements for manufacturers who did not have the capabil-ity to measure surface roughness to the level of precisionand accuracy required by SR applications. Based on ourefforts at providing feedback to the manufacturers, the qualityof optical surfaces delivered for use at the NSLS, and atother synchrotron facilities around the world, improvedsignificantly. For this work we were recognized with a FederalLaboratory Consortium Award for Excellence in Technol-ogy Transfer in 1989.

Surface Figure MetrologyDespite our successful efforts to have low Ångstrom-

level surface roughnesses made on aspheric optics, we quicklydiscovered that most of the conventionally-polished largecylindrical mirrors in use at the NSLS had large slope er-rors that broadened the image and seriously compromisedthe intrinsic source brightness of the machine. Figure mea-surement techniques for SR mirrors were extremely crudeat this time. There were no commercial instruments ca-pable of measuring grazing incidence aspheres with therequired accuracy, so the final product was seldom withinthe desired range of specification for both surface rough-ness and figure error. After finding an effective solution tothe surface finish measurement problem, we then turnedour attention to the figure measurement problem.

Early in the 1980s, a surface profiling technique wasdeveloped by von Bieren at Rocketdyne Corp., which wascalled the pencil-beam interferometer, that was ideally suitedfor the measurement of long cylindrical aspheres. A devel-opment effort was started at BNL to apply this technique,and an instrument incorporating an improved version ofthe interferometer was developed, which we called the LongTrace Profiler (LTP). The LTP is optimized for measuringthe figure and slope errors on meter-long aspheres thathave a long radius of curvature in the axial direction. It canhandle surfaces with a total slope change of 10 mrads withbetter than 1 µrad repeatability. Despite the limited angularacceptance range, the LTP can handle about 99% of allmirrors used in grazing incidence optical systems. As withthe micro PMI, we provided feedback to manufacturersand have seen a steady improvement in the quality of SR

LASER SOURCE

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mirrors, not only for the NSLS, but for all SR facilities forwhich the mirrors were destined.

Recognizing the usefulness of the LTP in the manufac-ture of SR optics, Continental Optical Corporation obtaineda license from BNL to manufacture the LTP as a commer-cial product. Under the auspices of a CRADA establishedwith BNL, an improved version of the instrument, the LTPII, was developed. At present, there are twelve LTPs inoperation around the world. It has become the de factostandard for the measurement of SR mirrors. The CRADAwith Continental Optical continues today with the goal ofdeveloping new uses and applications for the LTP technol-ogy. Under the present program, an In-Situ LTP (ISLTP) isbeing developed to measure distortion in SR mirrors underactual high heat load operating conditions. This work isbeing done in collaboration with the Advanced Photon Sourceat Argonne National Laboratory. We are also assisting Con-tinental Optical in a Phase II SBIR program to develop aVertical Scan LTP (VSLTP) for measuring complete x-raytelescope mirrors for NASA Marshall Space Flight Center.

The LTP II received an R&D 100 Award in 1993 asone of the most significant instruments of the year. It alsoreceived a Photonics Circle of Excellence award in 1993for innovation in optical instrumentation. Our efforts atrecognizing the commercial potential of the LTP resultedin a Federal Laboratory Consortium Technology Transferaward in 1997.

� Schematic diagram of the LTP optical system. Slope of the testsurface is measured by scanning the optical head across thesurface. Reference mirror removes all motion-induced errorsignals, allowing for extremely high precision and accuracy inlong radius of curvature measurements.

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Significant Accomplishments• Developed the Long Trace Profiler (LTP) for

measuring the surface figure of large asphericx-ray optics with unprecedented precision andaccuracy. This instrument is now the de factostandard for synchrotron mirror metrologythroughout the world.

• Developed accurate quantitative methods formeasuring surface roughness on precision opticalsurfaces with a micro phase-measuring interferom-eter instrument. Fully characterized the perfor-mance of the instrument through analysis of thesystem transfer function.

• Developed a surface roughness specificationtechnique based on the PSD formulation andfractal theory. This technique is now incorporatedinto an ISO surface roughness specification.

• Developed quantitative formulation to link x-rayimage quality to the surface PSD function.

• Developed a standard artifact for diagnostics andcalibration of scanning probe microscopes, stylusprofilers, and optical profiling instruments

• Successful technology transfer program withContinental Optical Corporation for continued LTPdevelopment through CRADA and SBIR programs

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ReferencesE.L. Church and P.Z. Takacs, “Survey of the finish characteris-

tics of machined optical surfaces,” Optical Engineering 24(3), pp. 396-403, (1985).

E.L. Church, “Fractal surface finish,” Applied Optics 27 (No. 8),pp. 1518-1526, (1988). BNL 41043.

P.Z. Takacs et al., “Long trace profile measurements oncylindrical aspheres,” Proc. SPIE 996, pp. 354-364, (1989).

P.Z. Takacs, “Understanding the Performance of X-ray Mirrors,”Synchrotron Radiation in Structural Biology, Robert M.Sweet and Avril D. Woodhead, eds., p. 303-316, PlenumPublishing Corporation (1989).

P.Z. Takacs et al., “Surface topography measurements over the 1meter to 10 micrometer spatial period bandwidth,” Proc.SPIE 1164, pp. 203-211, (1989).

E.L. Church and P.Z. Takacs, “Specification of surface figureand finish in terms of system performance,” Applied Optics32 (19), pp. 3344-3353, (1993).

P.Z. Takacs et al., “A Step-Height Standard for Surface ProfilerCalibration,” Proc. SPIE 1993, pp. 65-74 (1993).

E.L. Church and P.Z. Takacs, “BASIC Program for PowerSpectrum Estimation”, BNL Informal Report, BNL 49035rev. 5/94 (May 1993).

E.L. Church and P.Z. Takacs, Surface Scattering, in Vol. 1 ofHandbook of Optics, Michael Bass, ed., p. 7.1 - 7.14,McGraw-Hill, Inc. (1995).

S. Qian, W. Jark and P.Z. Takacs, “The Penta-Prism LTP: ALong-Trace-Profiler with Stationary Optical Head andMoving Penta-Prism,” Review of Scientific Instruments 66(3), pp. 2562-2569, (1995).

S. Qian et al., “In-Situ Surface Profiler for High Heat LoadMirror Measurement,” Optical Engineering 34 (2), pp.396-402, (1995).

P.Z. Takacs and E.L. Church, “Surface Texture”, in ISO 10110Optics and Optical Instruments - Preparation of drawingsfor optical elements and systems: A User’s Guide, R.K.Kimmel and R.E. Parks, editor, p. 50-62, Optical Society ofAmerica: Washington, D.C. (1995).

P.Z. Takacs and C.J. Bresloff, “Significant Improvements inLong Trace Profiler Measurement Performance,” Proc.SPIE 2856, pp. 236-245 (1996).

P.Z. Takacs et al, “Mirror Distortion Measurements with an In-Situ LTP,” Proc. SPIE 3447, pp. 117-124 (1998).

P.Z. Takacs, K. Furenlid and L. Furenlid, “Damage Observa-tions on Synchrotron Beam Line Mirrors,” Proc. SPIE3427, pp. 401-410 (1998).

� ISLTP measurements made at an APS beamline on a side-cooled Si mirror, showing changes in surface curvature as afunction of exposure time to the SR beam. Initial transientdeflection is convex; steady-state concave departure fromnominal occurs after about 30 minutes of exposure. This steady-state condition was not predicted by finite element calculations

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LASERS AND ELECTRO-OPTICS

T. Srinivasan-Rao

T. Tsang

J. Schill

Photocathode ResearchIn the past decade, RF injectors have been used as

high brightness electron sources for free electron laser andaccelerator research. The novel component in this injectoris the photocathode, which is incorporated into the RF cav-ity and acts as the source of the electrons. The ease withwhich the electron bunch parameters such as charge, cur-rent, current density, and spatial and temporal profile canbe modified is a major advantage of these injectors. Thecomplexity of the injector is determined primarily by thechoice of the photocathode material and the laser systemthat drives the photocathode.

The photocathode materials that have been used so farcan be broadly categorized into two types: cesiated semi-conductors and simple metals. The cesiated semiconduc-tors typically have a very large quantum yield and can bedriven by a simple laser system This advantage is offset bythe delicate nature of the material. Its susceptibility to con-tamination reduces the lifetime to a few days and necessi-tates use of complex preparation techniques and vacuumlevels below 10-9 Torr. The metal cathode, on the otherhand, is relatively insensitive to contamination and has avery long lifetime, but it has a low quantum yield.

The research in the Instrumentation Division is fo-cused on various methods to improve the quantum yield ofmetal photocathodes. A wide variety of techniques, such asin situ surface ablation, energy transfer via surface plas-mon or multi-photon processes, optical field enhancement,surface field enhancement, and Schottky effect, have beentested and shown to improve the quantum yield. More thana dozen metals have been tested for their photoelectricproperties and laser-induced damage properties.

Behavior of these metals under RF fields is being in-vestigated in an ongoing experimental program at the Ac-celerator Test Facility (ATF) in collaboration with scientistsfrom the NSLS. Recent experiments with bulk Mg, ion

The Laser Laboratory in the Instrumentation Division is actively involved in the develop-ment of efficient, high quality photoelectron sources, optical versions of particle detectorswith high spatial and temporal resolution, and diagnostics for ultrafast laser pulses. Variouspulsed and continuous wave laser systems are used in these research programs, with laserpulse durations of a few tens of femtoseconds to a few microseconds, with wavelengths in therange from ~1300 nm in the Infrared to 248 nm in the ultraviolet, and with energies ofnanoJoules to nearly one Joule per pulse. In addition to these lasers, the laboratory also has anunique high voltage pulse generator capable of delivering 1 MV in <1 ns with rise and falltimes of <150 ps. This pulse generator is used along with the fast lasers to generate electronbeams with unprecedented brightness. These fast lasers are used for detector applications aswell as for the development of diagnostic tools for ultrafast optical events.

� Experimentally measured quantum efficiencies of variousmetal photocathodes in the linear and the nonlinearphotoemission regimes. It is expected that the nonlinear processwill be more advantageous at high intensities before laserdamage is initiated.

sputtered Mg, and bulk Cu indicate that current densities of40 kA/mm2 could be obtained without damaging the metalsurface. This is the highest current density reported so farfrom macroscopic metal electron emitters. We have alsoestablished a preparation technique for reliable cathode per-formance.

Currently, our Laboratory is the only facility wheremetal photocathode research is being done for this applica-tion. These results are used extensively worldwide in choosingthe cathode materials. A number of academic and commer-cial institutions, such as UCLA, CERN, Argonne Nationallaboratory, MIT, and Grumman-Northrup, have been usingmetal cathodes based on this research.

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Generation of High Brightness ElectronBeams

Future electron colliders will require bunches of highluminosity, very high brightness electron beams. Short wave-length free electron lasers (FELs) also will require highcurrent electron beams with emittance comparable to thewavelength. Research in the Instrumentation Division intothe generation of such high brightness electron beams fol-lows two parallel paths: RF injectors and pulsed powerguns.

RF Injectors

In a typical electron beam, if the transport at high en-ergy is designed carefully, the emittance and the brightnessof the electron beam is dominated by its emittance andenergy distribution at the source or the cathode. Both pa-rameters are affected by the field seen by the electronswithin the cathode. This field is a combination of the sur-face field due to the applied RF and the space charge fielddue to electrons in the vicinity of the cathode. The velocitydistribution of the emitted electrons, and hence the trans-port of the electrons, are also affected by this dynamicfield.

A collaborative effort at the ATF between scientistsfrom the Instrumentation Division and the NSLS is investi-gating electron emission and the properties of electrons atthe cathode in an RF injector. In the most recent experi-ments, the emitted charge was measured as a function ofthe RF phase at which the laser illuminated the cathode. Adynamic model that takes into account the variation of thefield in the emission regime, and its impact on both emis-sion and transport of subsequent electrons, is currently be-ing developed. The model will also provide informationabout the temporal shape and momentum distribution ofthe electrons at the source, and can be used to optimize thelaser parameters to reduce the longitudinal emittance.

This dynamic model represents, for the first time, thatelectrons can be characterized accurately at the source. These

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characteristics can be used to optimize input parametersfor beam transport. The emittance growth in the injectorcan then be minimized and the brightness of the electronbeam can be improved significantly. From a practical pointof view, this research has also led to the development ofsurface preparation techniques for achieving the highestpossible quantum yield and reliable performance from thecathode.

Pulsed Power Gun

The inherent emittance and brightness of the electronbeam from the RF injectors are limited by the temporal andspatial variation of the applied RF field at the cathode asthe electrons are emitted and transported. The space chargeforces experienced by the electrons in the vicinity of thecathode, where the electrons are nonrelativistic, also affectthe brightness adversely. Nonlinear correction techniquesthat minimize these effects in RF injectors are being stud-ied.

Another technique to minimize the emittance growthdue to the varying field is to use a pulsed electric field atthe cathode. For this scheme to be successful, the pulseduration of the high voltage must be significantly longerthan both the emission time and transport time of the elec-trons in the nonrelativistic regime, and the electrode geom-etry should be optimized for minimum field variation overthe emitting area. In addition, very large fields should beestablished at the cathode to overcome the space chargeeffects.

The highest field that can be maintained at the cathodeis limited by the occurrence of electrical breakdown. It hasbeen shown that field gradients exceeding 1 MV/m can besupported by carefully prepared electrodes for durations of1-5 ns without breakdown.

To satisfy these requirements, a high voltage pulserwith a pulse duration of ~ 1 ns, rise and fall times of ~150ps, and an amplitude of ~1 MV, has been constructed. Withsuch a pulser, field gradients of 1.6 GV/m have been sup-ported using a copper cathode and a stainless steel anodewithout significant dark current. Electron beams of supe-rior quality can be obtained by irradiating the cathode si-multaneously with a short pulse laser.

Computer simulations for a 1 nC charge and 10 psduration from 0.25 mm radius spot indicate that, with suchfields, the transverse emittance of the electron beam couldbe an order of magnitude smaller than that currently avail-able. This improves the brightness of the beam by twoorders of magnitude. By optimizing the electrode geom-etry, even higher currents can be generated with similaremittances. Such an optimization is currently underway.Experiments are in progress to produce a 1 nC bunch witha 100 fs duration and to characterize the beam. Such anelectron source will be highly desirable for both high-en-ergy electron colliders and short wavelength free electronlasers. This electron source is capable of producing beams

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with unprecedented brightness (>1016A/m2rad2). Already,a number of institutions such as the Lawrence LivermoreNational Laboratory and the Source Development Labora-tory in BNL have shown interest in using this device as anelectron source. This device can also be used to generatemicrowave radiation at frequencies >30 GHz, and opticalradiation at wavelengths <1000 Å.

An SBIR Phase II grant has been awarded for the con-struction of a similar electron gun. A CRADA has alsobeen established to use our device as a working model.This project has also proved to be a sound learning groundfor graduate students, since it encompasses a wide range oftopics such as lasers, high voltage systems, electron opticsand electron diagnostics, and yet is small enough for oneperson to be responsible for all these systems.

Electro-Optics in Particle DetectorsAnother area of development in the Instrumentation

Division is to apply state-of-the-art laser technologies tohigh energy physics particle detector development. Presentparticle detectors are exclusively electronic devices, fromdetector signal identification to signal processing. With thegrowth of the physical size of modern detectors and the

� The GV/m pulsed electron gun at the InstrumentationDivision

� Voltage trace at the cathode of the pulsed electron gun.Maximum voltage is 920 kV, duration ~700 ps, with rise and falltimes ~100 ps after deconvolution.

added complexity of various monitor and control channels,the number of necessary signal channels exiting a detectoris almost unmanageable. Furthermore, cross talk and EMinterference between channels often compound the diffi-culty of signal processing. We explore the possibility ofdetecting energetic particles by optical means and the transferof the signals using novel optical techniques.

Ultrafast particle detector

It is well known that the response time of the polariz-ability of optical crystals is in the femtosecond regime. Ifthe electric field produced by the relativistic charged par-ticle can be probed by such crystals, the passage of theseparticles could be detected with unprecedented temporalresolution, limited only by the bandwidth of the associatedelectronics. This scheme also has an added benefit of re-moving the detector from the vicinity of the interactionregion, reducing the real space required near the beam line.

A collaboration to explore this idea has been estab-lished between the Physics Department, AGS, Instrumen-tation Division, Montana State University, and the Universityof Pittsburgh. Preliminary experiments have been done atthe AGS using the ion source. Additional experiments havebeen performed using the electron beam at the ATF to ex-amine the temporal shape of the electron induced polariza-tion. A short 10 ps duration, 50 MeV electron beam passesin the vicinity of a phase modulator and induces a largeelectric field in the modulator. The perturbed field inducedby the electron beam is probed with a highly polarizedoptical beam propagating in the modulator. By measuringthe change in the ellipticity of the optical beam during thepassage of the electron beam, the risetime of the electronbeam induced signal has been measured to be less than 1ns, limited by the bandwidth of the photoreceiver. Uponthe success of these initial experiments, the project may beexpanded to the construction of a real detector. A Labora-tory Directed Research & Development (LDRD) grant hasbeen awarded to continue this work. If successful, this ideacould lead to the development of particle detectors withtemporal resolutions of a few picoseconds and spatial reso-lutions of a few microns and would be highly useful inboth hadron and lepton colliders.

Transfer of detector signal

In another approach, by replacing bulky copper signalcables with lightweight fiber-optic components, one coulddrastically reduce the mass-volume of particle detectors.We explore an optoelectronic analog system using arraysof novel vertical-cavity surface-emitting lasers (VCSELs)for the transfer of particle detector signals.

VCSELs have a planar structure that is relatively simpleto fabricate and mass produce. Unlike edge-emitting laserdiodes, where various steps of post optical processing areneeded to form the cavity mirrors, a set of Bragg reflectingcavity mirrors can easily be deposited on the VCSEL’s

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planar structure, leading to strong optical confinement andlower lasing thresholds below 1 mA. Such sub-mA thresh-olds can be driven directly by most front-end electronicsand contribute little thermal budget to the detector. Thelarge GHz bandwidth of the VCSEL is more than adequatefor the highest ~100 MHz collision rate planned today.Furthermore, the planar nature of the VCSEL array struc-ture simplifies the prefabrication alignment and facilitatesthe coupling to a ribbon fiber to yield multichannel of highoptical throughput in a small mass-volume optical data link.

In collaboration with Centre de Physique Des Particulesde Marseille (CPPM) and Sandia in New Mexico, a 64-channel demonstration version of an optical analog link, at850 nm wavelength using GaAlAs-GaAs multiquantum wellstructures, for transfer of a particle detector signal wasmade. It is based on a novel fabrication technique: selec-tively oxidized VCSELs developed at Sandia, where thein-situ oxide formation around the gain medium has im-proved many aspects of the lasing characteristics. The Vcselshave approximately a 1 mA threshold and emit 3 mW ofoptical power at the maximum operating DC current of10 mA.

At the Laser Laboratory, we are investigating severallasing characteristics of the VCSELs including the linear-ity, spatial profile, polarization effects, spectral analysis,and the relative-intensity noise, all affecting the perfor-mance of an optical data link. One undesirable intrinsiccharacteristic of the VCSEL is its undefined output polar-ization due to its azimuthally symmetric birefringence, re-sulting in large polarization switching noise. We are

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investigating a method to tailor the birefringence of a VCSELusing a high-peak-power femtosecond laser. By locally al-tering the birefringence of a VCSEL, one can possibly tai-lor the desired polarization output and suppress thepolarization switching noise allowing VCSELs to be usedin analog applications.

Ultrashort-Laser-Pulse MeasurementTechniques

With the advance of solid state ultrashort lasers, sub-10-fs laser oscillators are now widely available for manyapplications. Characterization of these ultrashort laser pulsesand other ultrafast optical events traditionally relies on thenovel frequency-resolved optical gating technique via op-tical second harmonic generation on some nonlinear crys-tals. However, the intrinsic time symmetry of the second-orderprocess limits its interpretation, producing a time-reversalambiguity.

In collaboration with Sandia at Livermore, a novel,ultrashort optical pulse measurement technique has beendeveloped that combines the surface third-harmonic gen-eration (THG) and the frequency-resolved optical gating(FROG) technique to yield measurements of ultrashort op-tical pulses. The full time-dependent intensity and phase ofan arbitrary low-power ultrashort optical pulse or eventcan now be measured experimentally and characterized theo-retically without a time-reversal ambiguity. THG is dipole-allowed, occurring in all materials with or without a crystalstructure. It was demonstrated in our Laboratory that sucha nonlinear THG process is much enhanced at an interfaceand is insensitive to phase-matching or excitation wave-lengths. Therefore, it can potentially be used to character-ize ultrashort optical pulses of various wavelengths downto the vacuum ultraviolet. Because the enhanced THG oc-curs within an optical wavelength on the surface wherematerial dispersion is absent, it is well suited for ultrashortoptical pulse measurements, particularly for laser oscilla-tors emitting pulses below the 10 femtosecond regime and/or at wavelengths where no nonlinear crystal is availablefor second-harmonic generation.

� Surface THG optical system. A pulse from a self-mode-lockedTi:sapphire laser is divided by a beam splitter. After one replicaof the pulse is delayed with respected to the other, a 20xmicroscope objective is used to focus the two colinearlypropagating beams on to the back surface of a 160-micron thickpiece of cover glass. Two autocorrelated THG beams each carrya fraction of a nanowatt signal power sufficient for the requiredspectral measurements. One of the THG beams is recollimatedand sent to a spectrometer equipped with a linear diode array forspectral recording. Spectrograms at various time delays, with 10-fs intervals, are collected and converted into a 256×256 pixelFROG trace. A set of measured and reconstructed FROG tracecontaining spectral cubic phase distortion is shown.

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This enhanced THG technique has also generated newdevelopments in optical microscopy and imaging. A majorchallenge in optical microscopy is to observe transparentsamples in a surrounding medium that has nearly identicallinear optical properties. However, a variation in their non-linear optical properties always exists and is most pronouncedat their interface. Using a focused ultrashort laser pulse togenerate a third-harmonic signal only at their interface, atwo-dimensional cross sectional image of a transparent ob-ject was recorded at the Weizmann Institute. This nonlinearsurface THG technique will be an efficient tool for map-ping objects, material distributions, and possibly biologi-cal tissues, that are otherwise invisible under a typicalmicroscope. At U.C. San Diego, a cross sectional image of

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� Interferometric autocorrelation of a 17.5 femtosecond pulsetrain measured on a simple GaP photodiode. Experimentalarrangement is identical to a conventional SHG autocorrelationbut without a phase-matching requirement and the need of aphotomultiplier tube.

a plant leaf has been generated using the surface THG afterproperly compensating the dispersion of some high nu-merical aperture optics. These developments marked thepossible use of surface THG as a characterization tool andan alternative method for imaging.

Recently, an ultrashort laser pulse autocorrelation mea-suring technique has been simplified employing two-pho-ton photoconductivity in a semiconductor. Using a GaAsPphotodiode that has a bandgap of 2.5 eV, the pulse durationof a mode-locked 17-fs Ti:sapphire laser (1.55 eV) hasbeen measured. The 2-photon photoconductivity has sev-eral key advantages over the conventional approach of us-ing SHG for autocorrelation measurements. First, the intrinsictime response of the nonlinear process is measured to beshorter than any laser pulses available. Second, no polar-ization dependence or phase-matching conditions are needed.Third, distortion due to group-velocity dispersion is mini-mized because the interaction length is limited to an opticalwavelength. Lastly, the simplicity of the design and thesuperior signal output results in an extremely compactmeasuring device.

However, like any other high-order autocorrelation tech-nique, the phase of an optical pulse is not precisely mea-sured in a 2-photon photoconductivity interferometricautocorrelation. Therefore, a full time-dependent, intensityand phase measurement technique that combines 2-photonphotoconductivity and FROG is being developed. Such atechnique would simplify the experimental arrangementyet provide sub-femtosecond resolution with detail phaseinformation.

ReferencesT. Tsang et al., “Frequency-resolved optical gating measure-

ments of ultrashort pulses using surface third-harmonicgeneration,” Optics Letters 21, p.1381 (1996).

T. Tsang, “Optical third-harmonic generation at interfaces,”Phys. Rev. A 52, p.4116 (1995).

T. Tsang and V. Radeka, “Electro-Optical Modulators in ParticleDetector,” Rev. of Sci. Instrumen. 66, p.3844, (1995).

T. Tsang, T. Srinivasan-Rao and J. Fischer, “Surface-PlasmonField Enhanced Multiphoton Photoelectric from MetalFilms,” Phys. Rev. B15 43, p. 8870 (1991).

T. Srinivasan-Rao and J. Smedley, “Table Top, Pulsed, Relativ-istic Electron Gun with 1 GV/m Gradient”, AIP ConferenceProceedings 398. S. Chattopadhyay and J. McCullough,eds., p. 730 (1995).

X.J. Wang et al., “Measurements on Photoelectrons from a Mgcathode in a microwave electron gun,” Nucl. Instrum. andMeth. A356, p. 159 (1995).

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VACUUM DEPOSITION ANDMATERIALS PROCESSING

R. P. Di Nardo

The Vacuum Deposition and Materials Processing Laboratory provides special electrical,optical, mechanical, and magnetic thin film coatings for particle and x-ray detector systemsfabricated within the Instrumentation Division, for researchers at BNL’s other divisions anddepartments, accelerators (AGS, NSLS, RHIC, Dynamitron and Tandem Van de Graaff) andreactor, and for other outside educational and research institutions (i.e., the Materials ScienceDepartment at Stony Brook University.) The Laboratory also provides vacuum brazing, heattreatment, and materials consulting services to BNL’s divisions and departments. Technicaland instructional support is also provided to BNL’s Science Education programs.

� Special coating chamber built for producing multilayer coatings for x-ray and neutronmirrors. It can handle substrates up to one meter in length. The cylindrical structuresprotruding from each side contain the translation mechanisms to move the substratesacross the target sources.

• Resistance and electron-beam thermal evaporation,and rf and dc sputtering systems for thin filmdeposition

• Vacuum ovens for soldering, brazing and heattreating

• Systems for leak detection

• Systems for measuring the physical properties ofmaterials.

The Vacuum Deposition and Materials Processing Labis listed in the Directory of Federal Laboratory Resources,U.S. Department of Commerce.

FacilitiesThe Vacuum Deposition and Materials Processing Labo-

ratory, located in Building 535B, contains a parts prepara-tion room (chemistry lab), a testing and measuring room,and a thin film deposition and vacuum furnace room. Theavailable equipment includes:

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ReferencesV.Kh. Liechtenstein et al., “Preparation and Evaluation of

Thin Diamond-like Carbon Foils for Heavy-ion TandemAccelerators and Time-of-Flight Spectrometers,” Nucl.Instr. & Meth. A397, 140-145, (1997)

C.F. Majkrzak et al., “Neutron Scattering for MaterialsScience,” Materials Res. Soc. Symp. Proc. 166, 1990.

H. Homa et al., “Structural Study of Fe/W Superlattices,”pesented at Americal Physical Society, March 1989.

Materials

Co films for Dept. of Materials Science,Stony Brook

Al and Cr coatings on Mylar window

Ni and Co films on Si wafers for Dept.of Materials Science, Stony Brook

Ag films

Ti-alloy films of Nb, Zr, and Mo, onglass and mylar substrates previouslycoated with a thin Ta layer

Al strips on cathodes

100 foot lengths of continuously-coatedaluminized mylar

Reference

M.S. Zhu et al, “Microscopic Magnetic Characterization of SubmicronCobalt Islands Prepared Using Self-Aligned Polymer Masking Tech-nique,” IEEE Trans. On Magnetics, 33 (5) Sept. 1997.

P. Rehak, G.C. Smith and B. Yu, “A Method for Reduction of ParallaxBroadening in Gas-based Position Sensitive Detectors, IEEE Transac-tions on Nuclear Science, 44 (3), June 1997

M.S. Zhu et al, “Magnetic Nanopatterning with Block Polymers,”Materials Research Society 1996 Fall Meeting, Boston, 2-6 Dec 1996

T. Tsang, “Surface-plasmon-enhanced third harmonic generation in thinsilver films,” Optics Letters, 21 (4) 15 Feb 1996

C.M. Vitus and H.S. Issacs, “XANES Measurements of Oxide Films in TiAlloys,” The Electrochemical Society 1995 Fall Meeting, Chicago, 8-18Oct 1995

M.S. Capel, G.C. Smith and B. Yu, “One- and Two-dimensional x-rayDetector Systems at NSLS Beam line X12B for Time-resolved and StaticX-ray Diffraction Studies,” Rev. Sci. Instrum. 66 (2), Feb. 1995

A. Piotrowski, R.L. Gill and D.C. McDonald, “A New Tristan ThermalIon Source,” Nucl. Instr. and Meth. I 224, (1984)

R.P. DiNardo, C.F. Majkrzak and D.A. Neumann, “Fabrication of

Neutron Polarizing Fe-Si Multilayers by Sputtering,” Proc.

SPIE 983, 149-154, 1989.

C.F. Majkrzak et al, “Fe-W Supermirrors for Polarizing Neutrons,”

MRS Symp. Proc. 103, 115-120, 1988

R. Beuttenmuller et al., “Silicon Position Sensitive Detectors for the

HELIOS (NA34) Experiment,” Nucl. Instr. & Meth. A253, 500-

510 (1987)

R.P. DiNardo et al., “Sputter Deposition System for Controlled Fab-

rication of Multilayers,” Proc. SPIE 563, 30-35 (1985)

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FacilityThe principal scientific equipment contained in this

Facility is a 13 meter long optical relay system that can beconfigured to operate in several different modes: as a spec-trophotometer, as a system for measuring luminescencespectra and intensity, as a radiation damage source, etc.The figure shows the irradiation chamber and the equip-ment used to make measurements during irradiation.

As presently operated, spectral transmission or absorptionmeasurements can be made at any wavelength between219nm and 1000nm at temperatures between 4K and 900°C.Additional equipment can be installed in the Facility, e.g. astress-strain machine to study the effects of strain appliedduring irradiation. Also, to study luminescence, the photo-tube is replaced with a scanning spectrophotometer. Allcontrol functions and data recording are performed by acomputer.

A typical radiation-induced color center formation studyconsists of a cycle of measurements made at selected wave-lengths which is repeated at selected time intervals. Also,most studies are continued after the irradiation has beenabruptly terminated to study the decay of the coloring, phos-phorescence, and other properties of the radiation-induceddefects.

With an upgrade of the spectrophotometer system, itwill soon be possible to make simultaneous optical absorp-tion and luminescence emission spectrum measurementson strongly emitting luminescent materials, such as crys-tals, plastic scintillators and other materials used in particledetectors, during irradiations ranging from the highest tolowest dose rates. Optical absorption measurements are cur-rently restricted to non-luminescent or weakly luminescentmaterials during irradiation, or to strongly luminescent ma-terials after irradiation.

SOLID STATE GAMMA-RAYIRRADIATION FACILITY

M. CitterioJ.A. Kierstead

� The experimental equipment for making simultaneous opticalabsorption, radioluminescence, and other measurements onsamples during 60Co gamma-ray irradiation.

Co60 Source

Lead Shield

SAMPLE

STRAINAPPARATUS

GAMMA-RAY INTENSITY ADJUSTED BY MOVING SOURCE

VISIBLEUV

CHOPPER

MONOCHROMATORSPHOTOTUBE

BEAMCATCHER

CONCRETE SHIELD

The Solid State Gamma-ray Irradiation Facility (The Brickpile) was designed for basicradiation damage studies on transparent nonmetals. The “walk-in” irradiation chamber isroughly 14 × 14 feet and is surrounded by a concrete block shield sufficiently thick to permitpeople to work adjacent to the shield during irradiations. The existing Facility was completedin 1965. It was preceded by a prototype with a relatively low level source. In 1991 the 60Cosource in the Facility was upgraded to approximately 20,000 Curies. As of January, 1998 theconveniently obtained dose rates, on samples roughly 8 by 8 inches, range from approxi-mately 104 to 2 × 105 rad/hour. This can be increased to about 106 rad/hr for small samples. Byremotely moving the source and its shield the dose rate at a fixed sample position can bechanged, even during an irradiation.

Studies completed with this equipment have unequivo-cally demonstrated that the radiation damage levels in al-most all nonmetals is higher during irradiation than afterirradiation; in some materials appreciably higher. Thus, toreliably evaluate the extent of radiation damage in a trans-parent material to be used in a radiation field, it is essentialto make measurements during irradiation. Usually mea-surements are made at room temperature, but measure-ments can be made at temperatures between liquid helium

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temperature and roughly 1000° C with installation of theappropriate thermal environmental chambers.

In addition to the spectral studies for which it wasoriginally designed, this Gamma-Ray Irradiation Facilityhas been very useful in a large variety of radiation damagestudies. It is particularly useful for making measurementsduring irradiation on items such as electronic circuit boards,optical lenses, prisms, biological samples, etc. Also, it hasbeen used extensively to irradiate equipment too large tobe irradiated in other radiation facilities. Recently the Fa-cility has been used to induce polymer crosslinking (StonyBrook) and to predose crystal oscillators used in satellites(FEI).

The Solid State Gamma-ray Irradiation Facility hasbeen used to measure the radiation-induced absorption, ra-dioluminescence, thermoluminescence, and other proper-ties of many materials. In the table below is a partial list ofmaterials, particularly of scintillation crystals, that havebeen studied extensively at this Facility.

MATERIAL

BaF2

CsI

PbWO4

CeF3

PbF2

YalO3

FeS2

PbCO3

Alkalai Halides

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RADIO COMMUNICATIONS ANDAUDIO SERVICES

G.T. WalczykR.L. Dumont The Radio Group in the Instrumentation Division does a number of essential behind-the-

scenes activities that help make life and work at the Laboratory function smoothly and safely.The Radio Group is responsible for installation and maintenance of on-site, NTIA-licensedspectrum dependent communications systems and services. These include maintaining all ofthe two-way radio communication systems for the Security Group and Fire & Rescue, PlantEngineering Utilities and Buildings & Grounds, and also for large experimental facilities suchas the AGS, RHIC, ATF, NSLS, and the Tandem Van de Graaff.

� The Radio Communications and Audio Services Group is responsible for audio-visualservices at many Laboratory functions. George Walczyk and Ray Dumont (front) areshown here at work at the AV console in Berkner Hall.

Perhaps the most recognized service provided by theRadio Group is the site-wide radio paging service. TheGroup currently maintains over 1,900 personal pagers. Thegroup is also responsible for set up and maintenance of theLab-wide emergency notification system, the Plectron sys-tem.

In addition to radio communications services, the Groupalso provides audio services for various Laboratory func-tions, such as meetings and conferences at Berkner Hall,

employee training, health seminars, and special BERA pro-grams. The group supervises the installation of and pro-vides maintenance for numerous public address systems atvarious locations around the Laboratory, such as at theHFBR, the Medical Department, and the BNL Firehouse.

Another service provided by the Radio Group is main-tenance of the local CATV system for Staff Services in theBNL apartment and dormitory housing areas. Staff are li-censed in various radio communications areas and provideconsulting services to the rest of the Laboratory.

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The Instrumentation Division is actively involved in collaborations with industries interested in commercializing tech-nologies that have been developed here as a result of our research and development activities. A number of CooperativeResearch And Development Agreements (CRADAs) have been established to promote the technology transfer processover the past several years. The CRADAs that have been established cover a wide range of Division activities, highlight-ing the versatility of the Division staff and the diverse nature of its expertise. Recent CRADA activities are summarizedin the following paragraphs.

TECHNOLOGY TRANSFER ACTIVITIES

CRADA BNL-C-99-12Partner: Brookhaven Technology Group Inc. in collabora-tion with Battelle Pacific Northwest National Laboratory

Award date: March, 1999

Principal Investigator: Triveni Srinivasan-Rao,

Title: Development of a high current, high gradient,laser excited, pulsed power electron gun

Our expertise in developing high brightness elec-tron sources and our unique capability to establish fieldgradients exceeding 1 GV/m on macroscopic surfaceshave resulted in a CRADA with Brookhaven Technol-ogy Group, Inc. to design and build a novel pulsed powerhigh brightness electron gun. Using the technology de-veloped in the Laser Laboratory, subpicosecond elec-tron bunches will be generated by optically irradiating ametal surface in the presence of ~ 1 GV/m field gradi-ent. The electron beam produced will have brightnessapproaching 1016 A/m2 rad2, which is 2 orders of magni-tude greater than the present level of 1014 A/m2 rad2, aparameter highly sought after for future linear collidersand short wavelength FELs.

This high current, fast pulsed, laser excited, elec-tron gun is an enabling technology with applicationsthat benefit research in linear colliders, Free ElectronLasers, cellular biology, molecular science, materialsscience, and the study of transient phenomena in thesub-nanosecond time frame. It will also be used to studyproperties of materials in the presence of high fields,such as dark current emission and high voltage break-down characteristics, that will provide information criti-cal to the development of high frequency acceleratingstructures. In addition, using bremsstrahlung radiationfrom these ultra short relativistic electrons, the gun isexpected to be an efficient source of x-ray photons forimaging transient effects in biological samples,microlithography and micromachining. These excellentbeam qualities will be augmented for the first time bythe simplicity and compactness of the device resultingin an efficient, affordable product with superior perfor-mance and unique capabilities.

CRADA BNL-C-97-05Partner: eV Products, Div. of II-VI, Inc.

Award Date: March, 1997

Principal Investigator: P. O’Connor

Title: Development of Multi-Channel ASICs forCdZnTe Gamma Ray Detectors.

A major contributor to the success of our Division inthe development of high energy particle detectors has beenthe development of monolithic circuits that advance thestate-of-the-art in circuit design. Recognizing our exper-tise in this area, eV Products, Inc. established a CRADAwith us for the purpose of designing multichannel CMOSpreamplifier and shaper ASICs with high leakage currenthandling capability to aid the commercialization of CdZnTe(CZT) gamma and x-ray detector arrays. The circuits pro-vide compact, high performance readout for medical imag-ing products under development by eV Products, Inc. Thepresent single and multichannel designs use novel circuittopologies to achieve low noise, low power, high DC sta-bility, high dynamic range, baseline restoration and highdrive capability.

CRADA BNL-C-97-03Partner: Symbol Technologies

Award Date: May, 1997

Principal Investigator: P. O’Connor

Title: Microcircuits and Sensors for Portable Low-Power Data Collection and Transmission

Our expertise in developing new CMOS circuits hasresulted in a CRADA with Symbol Technologies for thedesign, fabrication, and testing of two novel devices forwireless data collection and transmission: an opticalphotosensor array and a 2.4 GHz single-chip, frequencyagile radio transceiver. A significant milestone in the “ra-dio-on-a-chip” program was achieved with the demonstra-tion of a fully-integrated CMOS transmitter. We replacedthe transmitter section of an existing Symbol 915 MHzhandheld, cable-less bar code scanner with our IC andachieved error-free performance over a range of 60 feet.

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The next major circuit to be developed will be adirect-conversion AM receiver, using the same frequencysynthesizer already demonstrated in the transmitter forthe local oscillator. Both devices can be processed in astandard industrial CMOS integrated circuit process.

CRADA BNL-C-94-09Partner: Lockheed Martin

Award Date: March, 1995

Principal Investigator: John Warren

Title: Microfabrication of a High Aspect RatioMicro-Accelerometer

The fabrication methods developed in the Micro-fabrication Laboratory have been recognized as havingimportant commercial potential in the development ofnovel motion sensors. A multi-year CRADA withLockheed Martin Tactical Defense Systems of Archibald,PA, makes use of high aspect ratio lithography to fabri-cate components for a micro-accelerometer with threetranslational and three rotational degrees of freedom.The present design will replace 54 individually machinedcomponents in the original prototype with microfabricatedlevitation coils and capacitors. These microcomponentscan be batch-fabricated with improved accuracy leadingto significant cost savings in the final sensor. This pro-

gram has undergone three favorable DOE reviews and isscheduled for completion in September, 1999.

CRADA BNL-C-95-08Partner: Continental Optical Corporation

Award Date: February, 1995

Principal Investigator: P. Z. Takacs

Title: Development of an In-Situ Scanning SurfaceProfiler

A multi-year CRADA with Continental Optical Cor-poration was funded in 1995 to develop an In-Situ LongTrace Profiler (ISLTP) for the purpose of measuring thedistortion produced on mirrors by high heat load condi-tions in ultra high vacuum environments. A prototypeISLTP was assembled and taken to the Advanced PhotonSource at Argonne National Laboratory in September1997 to make measurements on a water-cooled mirror ina SRI-CAT beamline. The instrument performed ex-tremely well and measured a significant bending effectthat was not predicted during the mirror design process.The success of the prototype ISLTP at the APS resultedin a extension of the CRADA program for one addi-tional year in order to complete a second system for useat the NSLS.

� Wireless transceiver prototypedeveloped in the CRADA with SymbolTechnologies. Integrated circuit, center,is fabricated in 0.5 micron CMOS andoperates in the 2.4 GHz unlicensedradio band.

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