Log entry time 21:45:21 on November 17, 2008

Entry number 249438

This entry is a followup to: 249161

Followups:

• 250304 11/22/08 09:23 Jin 1% inconsistency between T3 scalar counts in bigbite and LHRS

More evidence shows that the accumulating count difference on scalar 
set (spin=-1;Hel=-1) is due to missing counting on LHRS scalar.

New evidence:
As shown below, bigbite fast clock scalar count diff of (Spin = -1, 
Hel=-1) - (Spin = -1, Hel=+1) is stable; however same plot on LHRS 
shows a declining. We known scalar pair (Spin = -1, Hel=+1) is working 
fine; and missing counts is consistent with climbing rate on bigbite-
LHRS plots. Therefore, the missing counts are from LHRS (Spin = -1, 
Hel=-1) scalar.

So far we know:
> Among 4x2 gated scalars, only left HRS (spin=-1;Hel=-1) is missing 
fast clock counting.
> The missing rate is on the order of 10^-5
> It's not (effectively) affecting low rate counting (like L1 
acceptance)
> The rate is correlated to data taking rate or scalar read rate, so 
it's not likely to be a gate signal problem or clock signal problem

Therefore, for data analysis, we can use bigbite scalar as main data 
source, and crosscheck with LHRS scalar to discover bit flips. 

Bigbite scalar is normal

LHRS scalar is missing counts