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Lucite Cerenkov Hodoscope A. Ahmidouch, S. Danagoulian SANE Readiness Review Meeting, June 26, 2008. Placed in front of BigCal at 240 cm from the target Needed to: Detect charged particles above threshold primarily electrons and pions with high efficiency.
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Lucite Cerenkov HodoscopeA. Ahmidouch, S. DanagoulianSANE Readiness Review Meeting, June 26, 2008 Placed in front of BigCal at 240 cm from the target Needed to: Detect charged particles above threshold primarily electrons and pions with high efficiency. 2. Provide useful position resolution at a reasonable cost. 3. Be insensitive to background particles coming from outside of the target chamber
The Lucite hodoscope of 28 detectors is built Picture of the Lucite Hodoscope at the April beam test
SANE Setup Lucite Hodo.
Lucite Cerenkov Hodoscope28BC-800 bars: 3.5 x 6.0 x 96.7--91.5 cm3 curved 6.0 cm 240 cm 3.5 cm
Specs: • 28 Lucite bars: BC-800, 3.5 x 6.0 x 96.7--91.5cm3, n=1.49, Beta_threshold =0.67, propagation of C-light by total Internal reflection. • Curved to 240 cm, Normal incidence from target • Edges cut at 45 deg (avoids reflections) • Light guides (4.9 x 6.0 cm2) to 4.9 cm (circular) • 2” PMTs: Photonis xp2268, 1.5 mm mu-metal cylinder covering PMT+Base+extra 5cm
Hodoscope / Platform (designed by A. Metzger) 28 Lucite bars Mag. Shielding box (0.5” thick)
Magnetic Shielding • The target magnetic field at the Lucite location is < 30 G • Dominating components perpendicular to PMTs • The PMTs are housed in a 1.5 mm mu-metal cylinder covering PMT+Base end extending an extra 5cm to cover the light guide • PMTs are shielded by an iron box 0.5-in thick, which reduces the field to a few Gausses
Electronics 60 (56+ 4 spares) channels of: • Timing Discriminators • Amplifiers or Fan/IN-OUT • High resolution TDC LeCroy 1872 • ADCs • Delay cables • HV cables • Available • ordered
Schedule of Tasks • Lucite Detector ready March 2008 • GepIII test April 1-3, 2008 • Analysis of beam test data on going • Detector final checkup on going, June-July (Light leaks, PMT signals, …) • Installation September 9, 2008 • Cabling in Hall September 16 • Data taking October 2008
Manpower • Two faculty: AA & SD • Two graduate students: • Martin Jones (MS thesis on SANE), will likely relocate to JLab in the fall • Sujeeta Singh • A couple of undergraduates • Undergraduates who participated in the construction of the detectors: Christopher James, Steven Vilayvong, Juleia Allen.
Beam Test (4/2008) Tested 2 sets of 8 Lucite bars each, with different electronics configurations: • Two types of TDC modules: TDC1877 and TDC1872 • Linear FAN-IN/OUT or Amplifiers • Timing vs regular discriminators • TDC1872, Amplifier, Reg. Discriminator • TDC1872, Amplifier, Reg. Discriminator • TDC1877, Amplifier, Reg. Discriminator • TDC1877, Amplifier, Reg. Discriminator • TDC1872, FAN-IN/OUT Timing Discriminator • TDC1872, FAN-IN/OUT Reg. Discriminator • TDC1877, FAN-IN/OUT Reg. Discriminator • TDC1877, FAN-IN/OUT Reg. Discriminator
Beam Test BigCal vs Lucite y-position
Beam Test ADC spectra
Beam Test Position resolution: 6.9 (100 ps TDC + Timing Disc.) – 7.9 cm
Summary • Lucite detector built and is basically ready. Scheduled to move to Hall C in September 9. • Analysis of beam test data is in progress • First analysis conclusions: • Use 25-50 ps TDCs and Timing Disc. to improve the 6.9 cm resolution • Amplifier vs Linear FAN-IN/OUT either is fine • Discriminators Timing Discriminators • Use ADCs for off-line analysis
Still to do: • Finalize the analysis of beam test data and fine tune the analysis software for the Lucite, summer 2008 • Conduct a final checkup of the detectors (June-July) • Install detector in Hall Sept. 9 • Cabling and Set up the electronics Sept 16. • Manpower adequate