Quartz Detectors A. Ahmidouch, NC A

1
Quartz DetectorsA. Ahmidouch, NC ATHall 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
  the
• standard HMS hodoscope design
• Needed to
• Provide a clean detection of charged particles
• 2. Provide a high level of background rejection
• 3. Provide accurate tracking efficiency
  determination

2
SHMS detector package side view Quartz
detector S2Y
3
(No Transcript)
4
Beam envelope X(-55,60cm) and Y(-50,55cm)10
quartz bars 115 x 11 x 2.5 cm3 , with 0.5 cm
overlap
5
Completed RD work so far
Completed RD task Prototype of Quartz
Detector By Dave Mack ? report 12/16/2007

• Summer 2006 Patrick McCarter NCAT 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

6

• 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 mm
• Checking with (many companies)
• Cosmo Optics
• Case Corp.
• New Rise Optics
• Advanced Glass Industries
• Use UV sensitive 3-in PMTs, Hamamatsu H6526

7
Radiation hardness
n-l dependence
8
Pulse height spectrum

• Index of refraction n 1.47
• Threshold velocity
• bth 0.68
• Qweak 150 pe, for 2.5 cm thickness
• gt 60 pe required

9
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

10
Status of funding

• NSF-MRI grant 228,847
• Quartz bars
• PMTs dividers magnetic shielding
• Some travel
• Regular NSF grant
• Travel
• Student labor

11
Schedule of Tasks

• 2008 Procurement and test of the prototype bar
  with cosmics
• 2008-2009 Procurement of quartz bars and PMTs
  build the 101 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)