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User name brads
Log entry time 21:41:16 on March 08, 2010
Entry number 311132
keyword=Moller calorimeter signals have significant DC offset, also light leak?There are significant DC offsets on many of the calorimeter signals coming out of the amplifier. Figure 1 shows CL1 (I think) with a 10mV offset in the blue trace. I checked a couple other signals and they had offsets at 10--15mV level too. The FADC inputs are A/C coupled on the board, so this won't affect the new DAQ, but I wanted to mention and log it since it can/will affect the linear sums going to the discriminator in the old DAQ. (My understanding is that the discrim. is not capacitively coupled -- if not, it probably should be.) The offset dial on the linear fan can compensate in the short term, but those things tend to drift with temperature and load...
It also looks like there is a minor light leak on this calorimeter block.
It probably opened up after all the handling getting the new
scintillators installed.
A copy of this log entry has been emailed to: romanip, glamazdi, brads
Figure 1
