Quartz Detectors A. Ahmidouch, NC A&T Hall C 12 GeV Workshop, August 4-5, 2008
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Transcript of Quartz Detectors A. Ahmidouch, NC A&T Hall C 12 GeV Workshop, August 4-5, 2008
Quartz DetectorsA. Ahmidouch, NC A&T
Hall C 12 GeV Workshop, August 4-5, 2008
Hodoscope S2 Placed at +265 cm from the focal plane, in front of the Lead-Glass calorimeter
Quartz detector S2Y: Most dramatic change from thestandard HMS hodoscope design
Needed to:
1. Provide a clean detection of charged particles
2. Provide a high level of background rejection
3. Provide accurate tracking efficiency determination
SHMS detector package side view
Quartz detector S2Y
Beam envelope: X(-55,60cm) and Y(-50,55cm)10 quartz bars: 115 x 11 x 2.5 cm3 , with 0.5 cm overlap
Completed R&D work so far:
• Summer 2006: Patrick McCarter NCA&T Undergraduate student worked on:– Use Monte Carlo ntuples to
define the size of the detectors– Ordered PMTs for cosmic tests– Selecting the appropriate UV
transparent glue
Completed R&D task: Prototype of Quartz DetectorBy Dave Mack report 12/16/2007
• Choice: Artificial fused silica, has good properties:
– UV transparent
– radiation hard*
– low luminescence
• BABAR DIRC tests Spectrosil 2000 (St Gobain) and JGS1-UV (Scionix) best choice.
Q-Weak uses spectrosil 2000
• Optical uniformity: optical grade polish 25 A rms, flatness 200 m
• Checking with: (many companies…)
– Cosmo Optics
– Case Corp.
– New Rise Optics
– Advanced Glass Industries
• Use UV sensitive 3-in PMTs, Hamamatsu H6526
*Radiation hardness
n- dependence
Pulse height spectrum
• Index of refraction n =1.47
• Threshold velocity
th = 0.68
• Qweak: 150 pe, for 2.5 cm thickness
> 60 pe required
To Do List:
• Build and test the prototype bar.• Build the 10 + 1(spare) quartz bars with PMTs.• Test quartz detectors.• Deliver the detectors to Hall C and mount them on
frame.• Assemble the quartz detector.
Not included:• Cables + Electronics• High voltage power supply
Status of funding
• NSF-MRI grant: $228,847– Quartz bars– PMTs + dividers + magnetic shielding– Some travel
• Regular NSF grant: – Travel– Student labor
Schedule of Tasks• 2008 Procurement and test of the prototype bar with cosmics
• 2008-2009 Procurement of quartz bars and PMTs build the 10+1 bars test with cosmics
• 2009-2010 Deliver quartz bars to Jlab and assemble on frame
• 2011-2014 Installation in SHMS and commissioning
Manpower• Two faculty: AA & SD• One graduate and one undergraduate student
(probably more)