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User name A. Camsonne
Log entry time 18:46:27 on August 25, 2009
Entry number 285969
keyword=Compton electron detector noise study and testsI added the ferrites with the help of Jack this morning, I haven't really seen a major. I might have found an interesting correlation. Noise if bigger when at lower threshold indicating still a bit of crosstalk. So when going down from 17 to 13 or 10 the noise increases which could explain the lack of major improvement of efficiency when lowering the threshold. I think one possible fix could be to use only the lower part of the detector and put a metalic plate instead of a discrimator board as additionnal shielding. I will check that tomorrow during the pass change.
I also try to ground a bit better the right side but have not seen major
changes so far. When it is quiet background is still aound 14 mV. So
better grounding shielding could still help.
A copy of this log entry has been emailed to: brossard@clermont.in2p3.fr,hyde@jlab.org
Figure 1 With ferrite
Figure 2 Without ferrite
Figure 3 Threshold of 10
Figure 4 Threshold of 13
Figure 5 Threshold of 200
