The GlueX Detector

20 October, 2004 GlueX Detector Review

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The GlueX DetectorCurtis A. Meyer

This talkNext talk


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The GlueX Detector

This talk will start with the physics goals of GlueX andwhat GlueX has to be able to do to achieve them

Present the detector as a whole and what the componentsdo individually and collectively.

Show that the GlueX detector can achieve the physics goals.

Follow up talks will go into much more detail on each of the individual detectors elements.


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Search for QCD ExoticsThe 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 n KL

1 1 ’1 b2 h2 h’2 b0 h0 h’0

h’2 K+1K- ! o K+ K-! +-K+K-


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Physics RequirementsA Good Partial Wave Analysis Requires: Hermetic Detector for charged particles and photons.

Uniform, understood acceptance.

Excellent resolution to reduce backgrounds.

Linear polarized photons.

High statistics data sets.

Sensitive to many final states.


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Rates High statistics means high rates

Initially 107 tagged /s Design detector for 108

JLab CLAS runs at 107 already.

At 107, the total hadronic rate is » 37kHz the tagged hadronic rate is » 1.4kHzAt 108, the total hadronic rate is » 370kHz the tagged hadronic rate is » 14kHz

Running at 107 for 1 year will exceed current photoproductiondata by several orders of magnitude and will exceed current data.

More on rates in the nextpresentation


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Topologies Incident 8-9 GeV Lorentz boost

p

X

n,p

t-channel meson photoproduction

t)» e- t

photons pions protons

~1

Ge

V/c

10-60o


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Background Topologies

p

X

n,p

photons pions protons

N* production is a significant backgroundto the simple t-channel production.

There is interesting physics in this channel,it is just more complicated to analyze.

backwards slow pions

forward


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The GlueX Detector

Tracking Calorimetry Particle ID

Magnetic Field


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The GlueX Detector


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HallD and GlueX


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The SolenoidLASS Solenoid Superconducting 2.24TUsed in Los AlamosMEGA Experiment.Moved to IUCF forrefurbishing Oct. 2003.


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The SolenoidClear Bore: 185.4 cm diameterMagnet Length: 495.3 cmSolenoid Field: 22.4 kGUniformity: +- 3% in clear bore +- 1% on axis

4 superconducting coils coils 1 & 2 are complete new gauges, insulation leaks and plumbing fixed pressure tested. Coils 3 & 4 are waiting for contract completion

Magnet Review Magnet Assessment at LANL “looks very good” March 2001. Now have experience from 2 coils Interim assessment later this year


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CalorimetryForward Calorimeter LGD Existing lead glass detector ~2500 blocks E/E · 0.036+0.073/E1/2

» 100 MeV · E · 8 GeV Barrel Calorimeter BCAL Lead-scifiber sandwich 4m long cylinder E/E · 0.020+0.05/E1/2

~20MeV · E · » 3 GeV 200ps timing resolution z-position of shower time-of-flightUpstream Photon Veto UPV Veto photons ~20MeV · E · 300 MeV

Expected o and resolutions


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Calorimetry


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Tracking

Forward Region FDC 4 packages of planar drift chambers anode + cathode readout six planes per package xy=150m active close to the beam line.

Central Region CDC cylindrical straw-tube chamber 23 layers from 14cm to 58cm 6o stereo layers r=150m z» 2mm minimize downstream endplate dE/dx for p<450 MeV/c Necessary for protons


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Tracking

Forward Region FDC 4 packages of planar drift chambers anode + cathode readout six planes per package xy=150 m active close to the beam line.

Central Region CDC cylindrical straw-tube chamber 23 layers from 14cm to 58cm 6o stereo layers r=150m z» 2mm minimize downstream endplate dE/dx for p<450 MeV/c Necessary for protons


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Tracking


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Particle Identification

Time-of-flight Systems Forward tof ~80ps BCAL ~200ps Start counter

Cherenkov Detector DIRC K p separation

dE/dx Information The CDC will do dE/dx p<450 MeV/c


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The DIRC design will accomplish the physics goals of the GlueX experiment.

There are collaborators interested in pursuing the DIRC design and construction.

The documentation discusses both a DIRC design and an atmospheric pressure Gas Cherenkov design. We do not believe that the latter will satisfy the physics requirements of GlueX.


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FTOF BCAL

CDC dE/dxDIRCCherenkov

Separation fromindividual systems


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p ! 1 p ! +-4 p

Acceptance » 0.99 » 0.98

Very High

Very uniform over PWA angles

cosGJ GJ

Acc

epta

nce


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Acceptance

p ! 1 p ! 8 p » 0.99 » 0.98

Very High

Very uniform over PWA angles

cosGJ GJ

Acc

epta

nce


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Partial Wave Analysis

p ! 1+n! ++-n

! +00n

p

n

X

m [GeV/c2]

GJ

a2

Double blind studies of 3 final states

Polarization

GlueX Monte Carlo


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LeakageIf your acceptance is not well understood, The PWA can “leak” one wave into another.

BNL E852 Result

Leakagefrom

non-exotic wavedue to imperfectly

understood acceptance

Exoticsignal

1(1600)


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neutral

charged

LeakageIf your acceptance is not well understood, The PWA can “leak” one wave into another.

Break the GlueX detector in Monte Carlo: distort B-field degrade resolution change hole sizes distort beam energy

Largest leakage is ~ 1/2% of a strong signal. a1(1++) $ 1(1-+)


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Partial Wave Analysis

Have been able to pull out signals that are ~1% ofa strong signal using PWA.

It is extremely difficult to produce leakage that isas large as 1%.

Assuming a good theoretical understanding, if hybrids are present at ~1% of normal mesons strength, this detector will be able to find them.


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Summary

The GlueX Detector has been optimized for Partial Wave analysis, and the design has been tested by carrying out these analyses on simulated data.

The combination of detector elements with their resolution requirements allows us achieve the GlueX physics goals.

You will see that the status of all the detectors in the following talks. Some exist, most are in R&D, with all stages of R&D.

The collaboration is satisfied with the very recent DIRC design for the Cherenkov detector.


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Acceptance

Acc

epta

nce

Acc

epta

nce

coshel

coshel

hel

hel


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Search for QCD ExoticsThe GlueX Detector Design has been driven by the need to carry out Amplitude analysis.

p

X

n,p

Photoproduction

1 b1 , f1 , , a1 1:.25:.25:.201(1300) , a1 ’1! KK, KK

b2 a1 , h1, a2h2 b1 , h’2! K1

K,

b0 (1300) , h1h0 b1 , h1h’0! K1K, h0

1 1 a1 ! ()()!h0 b1! () !

0! Final State Particles

§ K§ KL n p

The GlueX Detector

Documents

gluex detector reviewsearch

hermetic detector

tagged s design detector

gluex detectorcurtis

tagged hadronic rate

total hadronic rate

coils interim assessment

axis4 superconducting