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User name P. Monaghan
Log entry time 22:04:09 on January17,2005
Entry number 139532
Followups:
keyword=TDC delay time change
After looking on the oscilloscope at logic signals from E-16L and auxiliary channel 33 (which go into the TDCs) on the second floor of the counting house, Bodo determined that there was a difference of about 30ns between the arrival of the auxiliary and E/dE TDC signals. When we checked the TDC spectra on the online replay for an auxiliary, dE and E plane channels, we found the E and dE spectra had their timing peak at around 1500 channels, but the auxiliary spectrum had its timing peak at around 500 channels; the difference is around 1000 channels which equates to around 30ns - the same difference as viewed on the oscilloscope. Since the auxiliary TDC spectrum peak is around 600 channels wide, it starts close to the beginning of the TDC channel range, so we decided to remove some delay in the proton detector TDC gate. We made an escorted controlled access and removed the 14ns in TDC gate delay from the blue delay box (bottom left set of switches - see halog entry 138739). We will check again the TDC spectra when MCC restores beam.