Drift Chamber Review March 6-8, 2007 1 Overview of Requirements Forward and Central Drift Chambers...
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Transcript of Drift Chamber Review March 6-8, 2007 1 Overview of Requirements Forward and Central Drift Chambers...
1Drift Chamber Review March 6-8, 2007
Overview of RequirementsForward and Central Drift Chambers
Elton S. Smith
Jefferson Lab
Physics goalsOverview of Hall DTracking requirementsSimulation
2Drift Chamber Review Mar 6-8, 2007
Physics goals and key featuresThe physics goal of GlueX is to map the spectrum of hybrid mesons (gluonic excitations) starting with those with the unique signature of exotic quantum numbers. Normal mesons in the quark model cannot have exotic JPC.
Identifying JPC requires an amplitude analysis which in turn requires• linearly polarized photons• detector with excellent acceptance and resolution• sensitivity to a wide variety of decay modes
In addition, sensitivity to hybrid masses up to 2.5 GeV requires 9 GeV photons which will be produced using coherent bremsstrahlung from 12 GeV electrons.
Final states include photons and charged particles and require particle identification.
Hermetic detector with large acceptance for charged and neutral particles
3Drift Chamber Review Mar 6-8, 2007
The GlueX Detector Design has been driven by the need to carry out Amplitude analysis.
p
X
n,p
Photoproduction
1 → a+1 → ()() →
h0 → bo1→ () →
Final state particles ± K± p
h’2 → K+1K− → o K+ K− → +−K+K−
1 1 ’1 b2 h2 h’2 b0 h0 h’0
all charged
many photons
strange particles
1−+ 2+− 0+−
Search for QCD Exotics
Mass scale ~ 2 GeV
4Drift Chamber Review Mar 6-8, 2007
Event Topologies
t-channel meson photoproductionIncident 8-9 GeV t) ~ e- t
photonspions
protons
~1
Ge
V/c
10-60o
~5
GeV
/c
<20o
p→1(1800)p
5Drift Chamber Review Mar 6-8, 2007
Physics Requirements
GlueX is designed to search for JPC exotic particles which are identified in a partial wave analysis of exclusive final states.
The detector must have uniformity of response and hermiticity to minimize false sources of exotic waves (“leakage”).
Leakage can be affected by incomplete knowledge of the detector acceptance and by purity of the event sample.
We have chosen a solenoidal detector configuration (B = 2T) to provide an azimuthally symmetric and well-understood acceptance.
Gluonic excitations are expected to have typical hadronic widths and decay modes with relatively high multiplicities.
Sensitivity to multiple decay modes requires good momentum and angular resolution for both photons and charged particles.
6Drift Chamber Review Mar 6-8, 2007
6 GeV CEBAF
CHL-2CHL-2
Upgrade magnets Upgrade magnets and power and power suppliessupplies
12
Enhance equipment in Enhance equipment in existing hallsexisting halls
add Hall D (and beam line)
7Drift Chamber Review Mar 6-8, 2007
Overview of Hall D
Hall D is a new experimental hall to be located on the east side of the north linac
The project includes the design, construction and commissioning of the photon beam and experimental equipment in Hall D.
The detector incorporates existing hardware
• Solenoid magnet used for the LASS experiment at SLAC and the MEGA experiment at LANL
• Lead glass used in BNL E852
The GlueX physics collaboration (approximately 70 people from 25 institutions) has been active for seven years
The GlueX collaboration is leading the detector R&D and conceptual design efforts in Hall D.
8Drift Chamber Review Mar 6-8, 2007
Top View
75 m
Tagger AreaExperimental
Hall D
Electron beam
Coherent Bremsstrahlungphoton beam
Solenoid-Based detector
Collimator
PhotonBeam dump
Photon beam and experimental area
East arc
North linac
Tagger area
Hall D
ElectronBeam dump
9Drift Chamber Review Mar 6-8, 2007
Hall D Detector Layout
Electron Beam from CEBAF
Lead GlassDetector
Solenoid
Coherent BremsstrahlungPhoton Beam
CerenkovCounter
Time ofFlight
BarrelCalorimeter
Note that tagger is80 m upstream of
detector
Target
Central DriftChambers (CDC)
Forward Drift Chambers (FDC)
10Drift Chamber Review Mar 6-8, 2007
The experiment has sought out expert advice by requesting external reviews
Cassel Committee (Dec 1999) David Cassel (chair), Frank Close, John Domingo, William Dunwoodie, Donald Geesaman, David Hitlin, Martin Olsson, Glenn Young GlueX Electronics (Jul 2003) John Domingo, Andy Lankford (chair), Glenn YoungGlueX Detector Review (Oct 2004) Mike Albrow, Jim Alexander (chair), William Dunwoodie, Bernhard MeckingSolenoid Assessment (Nov 2004) John Alcorn, Robert Kephart (chair), Claus RodeReview of Tagging Spectrometer and Photon Beamline (Jan 2006) Juergen Ahrens (chair), Bernhard Mecking, Alan Nathan
The collaboration has responded to issues raised by these committees and developed the present solid foundation for further design and construction
Hall D/GlueX Reviews
Note: GlueX has also been reviewed by PAC23 (Jan 2003), PAC27 (Jan 2005), the DOE Science Review (April 2005), and PAC30 (Aug 2006)
11Drift Chamber Review Mar 6-8, 2007
The GlueX collaboration has designed and optimized the detector to study gluonic excitations. Many university groups have contributed to the R&D and development of major subsystems.
• Solenoid JLab, IU Cyclotron Facility
• Detectors• Tracking Carnegie Mellon, Ohio, JLab
• Calorimetry Alberta, Athens, Florida State, Indiana, Regina
• PID Indiana, Inst for High Energy Physics (Protvino), Oak Ridge, Tennessee, Florida
International
• Computing Carnegie Mellon, Connecticut, Indiana, JLab, Regina
• Electronics Alberta, Christopher Newport, Guanajuato, Indiana, IU Cyclotron Facility, JLab
• Beamline Catholic, Connecticut, Glasgow
• Infrastructure JLab
Institutional Responsibilities
Elke Aschenauer took over as Hall D group leader in December, 2006. The Hall D group was officially formed in the Physics Division and 12 GeV project in January.
12Drift Chamber Review Mar 6-8, 2007
Capability Quantity Range
Charged particles Coverage 1o < < 140o
Momentum Resolution (5o-140o) p/p = 1 − 3%
Position resolution ~ 150-200 m
dE/dx measurements 20 < < 140o
Time-of-flight measurements t < 60 ps
Cerenkov and /K separation < 14o
Barrel time resolution t < (150 + 50 /√E) ps
Photon detection Energy measurements 2 < < 120o
Veto capability < 170o
LGD energy resolution (E > 100 MeV) E/E = (3.6 + 7.3/√E)%
Barrel energy resolution (E > 20 MeV) E/E = (2 + 5/√E)%
LGD position resolution x,y, ~ 1 cm
Barrel position resolution z ~ 4 cm
DAQ/trigger Level 1 200 kHz
Level 3 event rate to tape 15 kHz
Data rate 100 MB/s
Electronics Fully pipelined Flash ADCs, multi-hit TDCs
Photon Flux Initial: 107 /s rate Final: 108 /s
Hall D Scope: Detector Design Parameters
13Drift Chamber Review Mar 6-8, 2007
Decay Modes
Sensitivity to a variety of decay modes removes dependence on model predictions.
1X b For example, for hybrids: favored
not-favoredX
Measure many decay modes!
To certify results, checks will be made among different final states for the same decay mode, for example:
b1 0 3
0 2
Should givesame results
14Drift Chamber Review Mar 6-8, 2007
Tracking Requirements
pmm p
For simple kinematicsFor the narrow resonance
~1%M
E + 1%E/E ~ 5%/√p/p ~ 2%, ~ 2 mrad
Charged particles Photons
In order to maximize signal to background and at the same time balance the contributions from photons and charged particles, we have set the following goals:
x ~ 5mm/√E
15Drift Chamber Review Mar 6-8, 2007
Illustrative example
Perfect tracking
Perfect calorimetry
nominal
Charged tracking resolution is dominated by multiple scattering
Charged tracking matched to calorimetry
Generate zero-width
16Drift Chamber Review Mar 6-8, 2007
Position resolution
Momentum resolution of ~2% requires
→ Material budget < 5% rad. length
→ Position uncertainties of < 150-200 m to remain small relative to the multiple scattering contribution.
Require CDC < 150 m
Momentum resolution at 900
p/
p
Require FDC < 200 m
17Drift Chamber Review Mar 6-8, 2007
Angular coverage in c.m.
Require coverage down to 1o in the laboratory
Cos GJ for X→
lab > 1o lab > 2oGenerated
X
18Drift Chamber Review Mar 6-8, 2007
Detector Elevation View
125o
11o
1o
25o
19Drift Chamber Review Mar 6-8, 2007
Forward Region FDC 4 packages of planar drift chambers anode + cathode strip readout six planes per package xy=200m active close to the beam line.
Central Region CDC cylindrical straw-tube chamber 25 layers from 10cm to 57cm ±6o stereo layers r=150m z = 2mm dE/dx for p < 450 MeV/c
Tracking
20Drift Chamber Review Mar 6-8, 2007
Detector Plan View
cryogeniclines
electronic racks
Central panel480 AC 3 phase
beam
solenoid Fcal
Cerenkov
Staging Area
door
overheadcrane
(two levels)
(two levels)
Hall D layout showing approximate location of readout electronics crates, and power distribution.
21Drift Chamber Review Mar 6-8, 2007
Tools used to evaluate design choices
Generated Physics Events
“Raw” Monte Carlo Data
Model of Detector
Reconstruction package
Partial Wave Analysis
Reconstructed Monte Carlo Data
Event Generator
GEANT3
Parametric Monte Carlo
HDFast
Complete model for CD-2• background rates
original model
Track finding and momentum fitting• hardware design
Photon reconstruction under development
parametric reconstruction
PWA studiesUnder development
22Drift Chamber Review Mar 6-8, 2007
Simulation and reconstruction
Momentum reconstruction applied to full GEANT simulation of event, smeared DC hits, no background. The GEANT simulation event and reconstruction software and are being used to understand detector performance (see next talk).
23Drift Chamber Review Mar 6-8, 2007
Models of detector performance
Parametric Monte Carlo 2004
Momentum Reconstruction
2007
24Drift Chamber Review Mar 6-8, 2007
Today’s Presentations
6. Reconstruction and prototyping (FDC) Simon Taylor
1. Overview
Simulation and reconstruction
4. Central Drift Chamber Curtis Meyer
5. Electronics Fernando Barbosa
3. Forward Drift Chamber Daniel Carman
2. Tracking and simulation David Lawrence
On-chamber electronics
25Drift Chamber Review Mar 6-8, 2007
Summary Mapping the spectrum of hybrid mesons provides essential experimental data on the physics of the strong interactions in the region of confinement and is one of the main physics motivations for the 12 GeV Project.
This program requires
Momentum resolution of ~ 2%
Angular resolution of ~ 2 mrad
Material thickness < 5% rad. length
(FDC) < 200 m
(CDC) < 150 m
Today you are asked to review the design of the Hall D drift chambers for use in this experimental program.