CDC Preamplifier Conclusion
From GlueXWiki
Conclusions on the ASIC Preamplifier
After discovering that the gas mixing system at CMU had malfunctioned, we switched to a premixed 90/10 Ar-CO2 mixture. Using the premixed gas, we were able to reproduce the observed behavior of old preamplifier. We then proceeded to compare the new preamplifier with the old preamplifier.
- The gain of the new preamplifier is about a factor of
two smaller than that of the old preamplifier.
- We also observed that the output range of the old preamplifier was from 0V to 1V. E.g. we mapped 1V onto ~4000 channels in the FADC. The new preamplifier has an output range of 0V to 0.5V, with 0.5V being mapped onto ~4000channels in the FADC. This change was made to match the new 72-channel 125MHZ FADC.
PreAmp tests with premixed 90/10 Ar/CO2 - software threshold