User name R. Michaels
Log entry time 18:33:00 on July19,2001
Entry number 66765
This entry is a followup to: 66761
keyword=Helicity counting on 2 armsThe fig 1 below shows how the number of helicity gates counted
is different between two helicities and different on the 2 spectrometer
scaler systems. Top plot shows the absolute count difference between
h+ and h- pulses on Left Spectrometer, it is varies from -3 to +2 counts
(not sure why root smears the points to non integer...). This difference is
almost ok (should be <= 2 in theory). Lower plot shows the "asymmetry"
in pulses counted (h+ - h-)/(h+ + h-) on Right Arm (An asy seemed more
meaningful than the abs. difference). It is anomolously about 1400 ppm in the
random mode, then jumped to 4000 ppm in toggle mode. This confirms
what Ron said about glitches on h+, but it does not explain the gate time
asymmetries on Left arm. My speculation on that was that it may be a problem
of scaler readout (the readout is quite different on the 2 spectrometers), e.g.
maybe the glitches cause the scaler FIFO or related software to miss or acquire
an extra helicity bucket. However, so far the time asymmetry is said (by others)
to affect the fastbus data equally to the scaler data.
FIGURE 1
