AFP QUARTIC Fast AFP QUARTIC Fast Timing SystemTiming System

James L PinfoldJames L PinfoldUniversity of AlbertaUniversity of Alberta

AFP QUARTIC Timing GroupUniversity of Alberta, University of Texas at Arlington, University of Giessen, SUNY Stoneybrook

The primary goal has been to have the AFP timing system fully defined for the AFP Technical Proposal:

The end result should be a system that can obtain 20 ps resolution at an instantaneous luminosity of 1033 and given funding could be built and installed by mid/late 2012, and a second stage system capable of 10 ps or better resolution at an instantaneous luminosity of 1034 and given funding could be built and installed by 2015.

AFP Baseline Timing Plan

Two types of Cerenkov detector are employed:

GASTOF – a gas Cerenkov detector that makes a single measurement

QUARTIC – two QUARTIC detectors each with 4 rows of 8 fused silica bar will be positioned after the last 3D-Si tracking station because of the multiple scattering effects in the fused silica.

Both detectors employ Micro Channel Plate PMTs (MCP-PMTs)

30 cm

The QUARTIC Baseline Detector

Each QUARTIC detector has 4 rows of 8 5mm x 5mm x ≤ ~10 cm long fused silica bars (end-2-end =16 measurements) allowing up to a 4-fold improvement of resolution over that of a single bar

The refractive index of fused silica is ~1.5 ( Cerenkov angle of 50o)

An array of bars is mounted at the Cerenkov angle to minimize the # reflections as the light propagates to the MCP-PMT.

This arrangement is intrinsically rad hard

AFP has been concentrating on developing this detector including the full electronics chain

An early QUARTIC Prototype

1) Use short bars and reflective light guide

PRO: Less time dispersionCON: less light

OR 2) Use longer bars as the light guide

PRO: more lightCON: more time disp.

New Alberta QUARTIC Prototype

We are also (in conjunction with Giessen) Testing Fused Silica Fibres

as a Replacement for Bars

Tests indicate the we can expect better time resolution with FS fibres (~30% better) – although less total light

Fibres will allow flexible/finer segmentation and also better mapping onto the MCPMT

MCP-PMT Requirements

Excellent time resolution: 20-30 ps or better for 10 pe’s

High rate capability: Imax ~ 3 A/cm2

Long Lifetime: Q ~ 10 to 20 C/cm2 needed at high luminosity

Multi anode: pixel size of ~6 mm x 6mm

Pore Size: 10 m or better

Tube Size: 40 mm round, 1 or 2 inch square

Need to have capability of measurements in different parts of tube between 0-2 ns apart, and in same part of the tube 25 ns apart

8

Burle/Photonis 64 channel 10 or 25 m pore has been tested extensively with test beam and laser and would be default for first stage except for lifetime issues

Micro-channel Plate PMT (MCP-PMT)

Pico-second Test Facility at UTA

UTA laser setup: with LeCroy Wavemaster 6 GHz Oscilloscope

HamamatsuPLP-10 405 nm laser pulser

10

Test-stand optical system

Beam Mode Fiber Mode

Laser Facility Test Results

If NPE x Gain ≥ 5 x 105 then timing independent of HV/gain

With sufficient amplification there is no dependence of timing on gain

Saturation (the reduction in amp). of the output signal due to the busy pores is a local phenomena

Timing vs. Gain

Cross-talk

The amount of signal sharing affects ability to measure two adjacent rows/columns independently

As one proton enters some time before the other, the second timing measurement shifts due to cross talk

Cross-talk ResultsTested a prototype Burle Planacon tube using variable length fibers

Examined both row and column effect of spillover signal 100, 250 and 500 ps before the target pulse

About 10% of the pulse is detected in adjacent, empty pixels

Data shows that early light is not significantly affected by later light

Later light mean time is shifted, but is not totally dominated by the early pulse

Late time measurement degrades significantly as Δt increases

Exploring ways to reduce this effect

Beam vs Fiber

Fiber timing not as good, but allows us flexibility for some characterization tests

The √N Effect

16.4 s 16.6 ps

Measure time difference of 4 separate fibers (10 pe’s) wrt laser

Note all values lessThan 35 ps due to intime leakage from neighboring pixels(29 for edge 22 for middle)

Correct for T0 offset, average and take new time difference:

Get 35/4=17 ps!

Need to verify in test beam

29 ps 22ps 23 ps 29 ps

17 ps

Timing – CERN Test-Beam 2008

Dt56.6/1.4=40 ps/Bar including CFD!

Time difference between two 9 cm quartz bars after the CFD implies a single bar resolution of 40 ps for about 10 pe’s

(expected 10 pe’s from simulations)

Npe=(area/rms)2

16

2 21 2 1

1

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so if 1 2 then / 2

t t t t

t t

6 mm

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Strip #

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(a) (b)

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QUARTIC Efficiency CERN TB

Use tracking to determine that QUARTIC bar efficiency is high and uniform

Shape due to vetocounterwith 15mmdiameterhole

17Sep. 6, 2010

CERN/FNAL 2010 Test BeamQUARTIC:

At the 2008 CERN test we got single bar resolution of 40 ps for about 10 PE’s – in 2010 test we are now seeing ~30ps single bar resolutionNew quartz bar prototype test (Alberta 8 long-bar prototype), use scope to measure raw signal and compare to laser, pulse height, number of PE’s, timing resolution8 channel electronics test AMP->CFD->HPTDC [sqrt(N) test] study coherent noise effects and 8-channel timingCompare 25 m and two 10 m Burle tubes (single channel & also 8 channel)

FIBRE:Giessen fiber detector with Giessen readoutRepeat for QUARTIC readout Alberta fiber bundle comparison tests

SiPM TESTS

ANALYSIS IN PROGRESS

Prelim TB results

QUARTIC Readout Electronics

Electronics has been tested at the UTA laser facility, the CERN Test beam in 2008 a CERN test beam in 2010 (August) and recently at a test beam at FERMILAB

The latest tests show that this electronics chain works with SiPMT as well as MCPMT readout

Electronics - Responsibilities Alberta: has upgraded Louvain CFD and developed HPTDC boardGoals:

Complete design of a 3 HPTDC chip, 8 channel HPTDC board based on successful one chip design (due to occupancy issues only 4 channels available/chip, and one of these is used for reference timing, so a 3 chip board gives 8+1 channels)

Documentation + further system tests, including connections with ROD

Radiation tests of CFD + HPTDC electronics

Stony Brook – Goals:Tests of chain PULSER==>Preamp==>CFD

SPICE model of the chain PreAmp==>CFD==>Trigger

Tests of trigger circuitry

Detailed design of PreAmp PCB

Detailed design of Trigger circuitry

QUARTIC Electronics – the CFD Mini-module approach

tuned LCFD mini-module to Burle and Hamamatsu rise times;

12 channel NIM unit good performance : <10 ps

resolution for ≥ 4 PE’s

Remote control for threshold

ZX60 3 GHz amp

QUARTIC Electronics – the HPTDC

12 ps resolution obtained with pulserSuccessfully tested at UTA laser test stand with laser /10 m

tube/ZX60 amp/CFD - 13.7ps resolution obtained with CFD~30 ps resolution obtained with real pulses at test beam

LCFD_Ch01_No12_spe, high level light, May 6, 2009, UTA laser test RMS resolution = 13.7 ps

0

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800 810 820 830 840 850 860 870 880 890 900

bin number

coun

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HPTDC Buffering Structure

The 6 mm pixel (PMT) which is closest to beam, would see max. hit rate is 15 MHz - the time interval between hits is ~67 ns;

Loss rate in the channel buffer, with the following conditions: Logic core clock = 40MHz, Only input channel 0 is connected;

Hit rate (MHz) Total hits Loss hits Loss rate

4 7190 7 9.74e-4

6 5117 45 8.79e-3

8 3160 107 3.39e-2

10 1424 118 8.29e-2

12 739 111 0.15

14 306 60 0.196

Loss rate in the channel buffer, with the following conditions: Logic core clock = 80MHz, Only input channel 0 is connected;

Hit rate (MHz) Total hits Loss hits Loss rate

8 53244 1 1.88e-5

10 7783 2 2.57e-4

12 9072 6 6.61e-4

15 10713 12 1.12e-3

18 5998 33 5.5e-3

20 2404 27 1.12e-2

22 2589 37 1.43e-2

24 2747 79 2.88e-2

Simulation Results – Loss RateStudy used HPTDC Verilog model

Standard version of HPTDC chip could work with a core clock frequency up to 80 MHzA special speed graded version of HPTDC chip could work with core clock of 160 MHz.RMS resolution is not affected when running with 80MHz clock.

But power consumption is increased.Need to use 2 channels “ganged” to take the maximum rate

8 channel board 4 channel board

Buffering Test Results

The Lifetime Challenge

Lifetime due to photocathode damage from positive ions is proportional to extracted charge:

Using a fiber detector we would accumulate 10-20 C/ cm2 /yr (assuming 5x104 gain) at the highest lumi

This is a factor of ~20 more than typical tube lifetime!

What To DoWe are pursuing the development of a tube with at least ~20 times longer lifetime, the avenues of improvement are:

Including an ion barrier (Nagoya solution) – giving a factor of 5 6 or more (latest SL10 results?)

Z stack design gives a factor of ~10 improvement (NIM A598,160,09)

Arradiance coated MCP’s: promises a factor of 10 or more lifetime improvement.

UTA have a funded Small Business Proposal with Arradiance and Photonis (starting Jan. 2011) to develop a long life MCP-PMT using Arradiance coated MCP's

Various combinations of these factors are possible and should give multiplicative improvement factors

Conclusion We have developed a fast timing system for AFP that seems

to be capable of ~10 ps resolution Work in progress:

1)final optimization of detector (quartz fibers could lower maximum rate by 2-3 by more sensible binning)

2) Developing final (3 chip) HPTDC board (Alberta) and trigger circuit (Stony Brook)

3) Test beam and laser tests

4)Developing and testing long-life MCP-PMT (new funding)

5)Evaluating radiation tolerance of all components and upgrading as needed

6)SiPm alternative

Write up results for Technical Proposal

EXTRA SLIDES

Study used HPTDC Verilog model & measurement, simulation details:

Hit rate:The number of interested interactions at bunch crossing (40 MHz) is on (Poisson) average of 25, from which each has a 3 % chance to hit QUARTIC detector, this gives a rate of 40 MHz *25*3% = 30 MHz;

The 6 mm pixel (PMT) which is closest to beam, would see max. hit rate is 30/2 = 15 MHz - the time interval between hits is ~67 ns;

A hit (track) strikes all input channels at the same time. The input channel the min. t between hits - 25 ns.

Trigger rate:ATLAS L1 trigger rate 100 KHz, with a trigger latency of 2.5 s;

The time interval between triggers is on an exponential distribution;

The minimum spacing between triggers is 25 ns

QUARTIC HPTDC Buffering QUARTIC HPTDC Buffering

TimingTriggerinTriggeringg

ConclusionsConclusions

04/20/23 31Manchester Forward Physics James Pinfold