First results on recoil detector prototype test

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First results on recoil detector prototype test

• E. Burtin, E. Delagnes, N dHose, V. Gorge, G.
  Jegou, J. Marroncle, F. Senée, T. Szczesniak
• CEA/Dapnia, Mainz U., Bonn U., Warsaw U.

Compass Collaboration Meeting, Nov 10,2006
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Experimental Set-up
All scintillators are BC 408 A 284cm x 6.5cm x
0.4cm Equiped with XP20H0 (screening grid) B
400cm x 29cm x 5cm Equiped with XP4512
Trigger AB coincidences finger pairs
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Motivations

• Prototype for a GPD experiment
• Low rates gt Large detector
• High background gt Sampling of WF
• Measure properties of the scintillator
• Speed of light, Attenuation length, light yield
• Measure timing and position resolutions in A and
  B
• Detect protons and study background
• CH2 Targets of various width and length
• Evaluate electronics chains
• 1GHz sampling of the signal
• 250MHz sampling standard multihit TDC

 tranverse 
 longitudinal 
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Sampling of the signals
Use 1GHz sampler MATACQ (developped by DAPNIA and
LAL) Standalone labView based DAQ 100 Hz
1Gb/hour
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Attenuation length
Obtained in calibration set-up with 5 pairs of
fingers
Upstream A2 PMT
Downstream A2 PMT
cm
cm
Measured values A1 2.2 0.2 m A2 2.3
0.2m B0 3.7 0.2 m B1 3.3 0.2m in
agreement with expectations
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Preliminary (online) results
Resolution of individual counters
A B n?e 50 900 Center 290 ps 200
ps Edge 400 ps 300 ps Center 266 ps 157
ps Compared to 280 ps 140 ps
Simulation CLAS(Jlab) Resolution on
TOF Center 340ps HV low Center 310ps HV high
expect resolutions of 280 ps after
analysis
HV low
HV high
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Longitudinal mode
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Beam-target Centering
Target ? 2.5 cm Beam RMS_x 2.8 cm Beam RMS_y
3.7 cm I2.5 108 muon/spill of 4.8s
Remote controlled (fishing wires)
unvetoed rates in A
-6
Recoil detector
-10
4cm
1MHz
-14
-6
Target Out -18
Predefined position is well centered
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Effect of the target

• Measured Simulation
• A 0.18 ? 0.06 MHz 0.14 MHz
• B 0.024 ? 0.008 MHz 0.031 MHz
• Measurement in 98 (A.Magnon et al.)
• 0.11 MHz (conditions similar to A)

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Proton signal
deuterons
?E in B (MeV)
protons
Target 10 cm CH 8 hours of data
Measured ß
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Whats next ?
Still 7 days of beam  beam telescope  Use
longer target (2m) Use wider target (5cm)
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Timing resolution
A2
B1
295 ? 12 ps 4.52 ? 0.19 cm
192 ? 9 ps 2.99 ? 0.14 cm
cm
cm
Resolution on z or (tup-tdown)/2 vL
Resolution on ToF (tuptdown)B/2 -
(tuptdown)A/2
322 ? 14 ps