Compton Meeting, October 12, 2011
Agenda
Laser
- Transfer function status
- Pull vacuum?
Photon Detector
- LED linearity system
- Detector
- Cooling system update
Electron Detector
- Source tests
DAQ
- Are we going the exchange VME crates?
MISC
- Joe has terminated new cables
- Need to hook up scanner, add lead
Notes from Meeting
Photon detector
Glued piece of Mylar on front of photon detector to mark location of crystals in container. PLT unreliable. When it is working it keeps the temperature stable to within a few hundredths of a degree; however, it goes into unstable modes and requires power cycling. Arthur suggests getting a replacement.
Pushing temperature 10 degree below room temperature gives 20% increase in yield. Further tests desired. Wouter wants to install in hall on Friday. More cosmic tests until then.
No further comments on linearity LED tests.
Electron Detector
All QWAD’s installed and being tested. Fourth plane appears to see no signal other than noise. Further tests ongoing. Ready for vacuum at any time if necessary.
Laser
Transfer function data taken three times: once with the old loose mirror holders on the primary (98%) beam through the holographic beam splitter(HBS) and once with the new mirror holders on the primary HBS beam and with no mirrors on the secondary 1% HBS beam. The actual transfer function has not yet been extracted from the data. Work is ongoing in this line. Once the TF is actually obtained, we will use it to predict the intracavity DOCP based on the exit line measurement and then check the result. If this prediction is correct, we will then be ready to reassemble the cavity region and pull vacuum. Estimate for vacuum ready is mid next week.
Linearity studies on photodiode used to measure TF and polarization during production running show nonlinearities ~1% over 10000 channels. A 1% nonlinearity in our linear polarization measurement is negligible for our level of accuracy and translates into <<1% error in DOCP for DOCP ~99%.
