User name R. Michaels
Log entry time 18:16:08 on July23,2001
Entry number 67284
keyword=False asymmetry in fastbus dataI analyzed today's data from 4 kHz pulser trigger of fastbus DAQ on Left arm.
to study false asymmetries and see if they were the same as observed
in the scaler data, where there has been an asymmetry in time for Left arm.
Helicity is flagged redundantly in 4 ADC channels, 2 for Hel+ and 2 for Hel-.
Helicity is either 1) unambiguously positive (all Hel+ signals high, Hel- low),
2) unamb. negative, 3) blanked (all signals low), 4) problematic (any other case).
Asymmetry is formed from the number of triggers in each helicity state.
Results for toggle mode (run 2202) and random mode (2203-7) are
Mode....Hel+ events.........Hel- events.......Blank...(%).......Problematic
Toggle......12,617,391........12,617,942.........384,187 (1.52%).......11
Random....13,992,273.......13,950,218.........354,080 (1.27%)........13
The expected blanking is 1.52% and 1.14 % respectively for Toggle & Random.
The Asymmetries are plotted in fig 1. Each point is the accumulation since
the beginning. Error bars are 1/sqrt(N), though this is silly since the events
are NOT random; I suppose the real error is much smaller and arises from
fluctuations in the timing. The asymmetries were -22 ppm and +1505 ppm
(sign: Hel+ - Hel-) resp. for Toggle & Random.
Meanwhile the asymmetries in gate time measured in scalers were
+12.6 ppm and +1280 ppm for Toggle and Random.
The setup was the usual one with the Phillips gate generator.
FIGURE 1
