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User name D. Parno
Log entry time 12:49:40 on December16,2008
Entry number 253617
keyword=GSO Compton spectrum in FADCLooking back at old data from last week, Gregg Franklin and I found a very nice GSO Compton spectrum in the FADC (new electronics/DAQ). The blue events are laser cavity on (Compton scattering) and the red events are laser cavity off (background). This is a histogram of the pulse integrals, so the x-axis roughly corresponds to the energy deposited in the GSO crystal.
The odd part is that, when this run was taken, the Counting DAQ was NOT showing a good Compton spectrum. Similarly, when the counting DAQ was showing a good Compton spectrum, we didn't see much in the FADC. Our theory is that the tube base (which shows some signs of melting/charring) may have had some bad internal connections at the beginning, explaining why signals were so small. If these connections were better a few days later (melted into place?), the Compton events may have been out of range of the Counting DAQ, and just in the right range for the FADC.
FIGURE 1
