Wide L0 in TC calibration runs.

Last updated 4/12/2003 11:29 AM

Run 11933. L0 time. All events. Strange bump at 473.
Reference for selections. Normal calibration peaks in one of the TOF channels are shown. The Time Calibrator was set to 640 ns range, 20 ns period, therefore we should see 32 positions. The 27 positions are clearly seen, the 5 positions hidden in the peak at 0. The peak at 0 corresponds to the events where the TDC Stop arrived before the TDC Start.	Events in the first 6 positions have normal peak at 468 and an admixture of the distorted peak at 472.
Events in positions 6 through 12 have only distorted L0	Events in 21 upper positions have good L0.

Summary:

The clue: For 10 lower positions (TDC_TC70<7000) the signals for channels 48:63 of this TDC09 (T0 channels) falls into the peak at 0 where the individual stops comes before the common start.

This is probably the evidence of the TDC non-linearity in the case when common start comes too soon after the previous stop.