User name paschke
Log entry time 13:02:15 on June19,2004
Entry number 126313
keyword=Bit resolution of Hall C bcm
Hall C turned on, so started using their BCM signal to measure (and
then zero) their charge asymmetry. They were running only 1 uA, so
we were somewhat limited by the bit resolution.
Figure one shows the raw bcm10 signal. The end of the run shows the
beam off in Hall C, the beginning is about 1 uA. This is 140 channels
over pedestal, which gives us a bit resolution of 1/(2*140) ~ 3500 ppm.
If this is a linear region of the bcm, at 20 uA (were they expect to
run this weekend) we will see only about 2800 channels over pedestal.
This is a bit resolution of 200 ppm, which is probably ok.