Minutes-5-19-2008
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FDC/CDC Meeting
Date: May 19, 2008
Participants: Daniel, Simon, Fernando, Mark, Beni, David, Curtis (phone), Yves (phone)
Next Meeting: June 2, 2008 @ 1:30 p.m.
FDC ASIC Dynamic Range Characterization
- Simon has been continuing to analyze cosmic ray data acquired with the small-scale prototype. Recently he has found that the cathode strips seemed to be plagued by random high-frequency noise. Simon has been working on algorithms to cut this noise out so that our amplitude and charge plots are not biased. His first cut was to require a minimum total charge in the FADC spectrum (5-microsec) wide of 600 pC. The noise events have a distribution that is basically centered about zero (qualitatively). - During the discussion, we laid out several alternative cuts and requirements to try to better separate the noise events from the good events. Note that Simon noticed that the anode signals are not as prone to noise as the cathode strips. This may be because the chamber grounding configuration has changed when Simon reassembled it with the 2 micron thick Cu planes. This will be looked into. - Fernando has all of the hardware necessary to characterize the gain of the ASIC boards, the shaper, and the 18-m long cable. He will perform measurements this week and circulate the results.
CDC ASIC Dynamic Range Characterization
- The CMU folks have tilted the CDC prototype to 60 deg (from the horizontal) and have been collecting pulse samples as a function of HV. These samples have been compared to the 0 deg configuration. At the nominal operating point chosen, it appears that the pulses are saturated, pointing to running (possibly) at too high a gain, and also to the ASICs/shaper having too high a gain.
Minutes prepared by Daniel. Send any comments or corrections along.