Wednesday, May 1, 2013 2pm EST - Compton

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Previous meeting: Thursday, March 28, 2013 1pm EST - Compton


  1. DAQ proposal trigger, coda (Bob)
  2. Detector proposal (Alex)
  3. Status of Compton e- detector 2010 report (Alex/Vladas/Rob)
    1. Compare to source tests, slide 4
  4. Diamond detector quotes summary (Juliette)
  5. Future work


  1. DAQ proposal (Bob)
    1. Electronics group meeting (Ben Raydo, Chris Cuevas, Alex, Sirish, Bob)
    2. Ben will write engineering specs after Bob writes "physicist" specs
    3. revised with feedback from Kent and Wouter Deconinck
    4. a prototype could be built in 14 weeks FTE (~8 months real time) for 7K$
    5. based on the JLab CODA-3 VXS pipelined FPGA-programmable technology - is this a standard size? 10x bigger than V1495 - 18x192 inputs
    6. Bob will send out revised versions once they are completed
    7. SOLID will need things like this, so this is like a SOLID test stand; elec. group happy to work on it
  2. Detector proposal (Alex)
    1. For proposal, I did not submit it. I was planning to focus on gaseous detector since it was new but
    2. it seems low pressure detectors work with highly ionizing particle (ions beams or protons), the number of primary I got from low pressure detector was too little
    3. need more information and simulation and optimize pressure and thickness of windows to make a proposal
    4. but can be at higher pressure, except in vacuum - tradeoff with thicker window (backgrounds)
  3. Status of Compton e- detector (Alex/Vladas/Rob)
    1. Detector was cabled and we look a bit at analog signal with Vladas. It is quite noisy right now out from the box I guess we can improve a little bit by checking ground and shielding but we are still far to be able to lower threshold to improve efficiency. Signal for MIP is around 12 mV.
    2. noise was 15-20 mV with 3/4 trigger already
    3. from source tests in Hall put detector in can - like a Faraday cage - in beamline now, flanges aren't attached...
    4. I picked up one QWAD (amplifier, discriminator, shaper) from Dave Gaskell to test it. I guess we will try to power it and try to check if it would work with our detector. But I think it is mostly coming from detector and bus
    5. Vladas mentioned that the QWAD feature a time over threshold function and that cutting on the pulse length reduced a lot of noise
    6. Attached is a document about noise, you can go through it if you have not seen it
    7. Take detector apart - test everything separately (except no noise outside of hall!) flex cables are antennas :)
    8. Do tests at TRIUMF?
      1. The guy - what's his name? - may be too busy - Wim will ask around
      2. QWAD/Hall A electronics/spare detector (to measure capacitance, etc.)
    9. Check QWADs in Hall A first to see if it is better than Hall A electronics
  4. Diamond detector quotes (Juliette)
    1. Summary - about $50k for full detector 46 mm long (wide?) (same as Si strip detector)
    2. $50k to replace what we have now
    3. Silicon was $16-20k for thin, thick was much higher
    4. wait for Si strip detector tests
    5. push forward to get diamond sample?
    6. only test charge collection distance if going with Applied Diamond
    7. standard detector - rather than a specialized
    8. they have prototypes from Hall C
    9. How big can they make it?
      1. improved estimates of how big we want it
      2. synchrotron radiation
  5. Future work
    1. Vladas and Alex will come up with a list of tests to possibly be done at TRIUMF
    2. Juliette will calculate the length and synchrotron radiation
    3. Need to replace HV connectors with electronic group
    4. Reduce noise on detector and try to check efficiency with trigger scintillator
    5. Adapt QWAD to spare detector

Next meeting in 4 weeks, expect a DOODLE poll in ~3.5 weeks :)

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