User name R. Michaels
Log entry time 11:31:08 on July23,2005
Entry number 149157
keyword=prelim. scan results (2 runs)
Results from the Y scan. Detectors all look ok.
Fig 1 shows the X,Y at target, the lower panels show my cuts for
"top" and "bottom" of acceptance. What matters is the ratio of
the number of entries in these "cut histograms". So, run 2232
(fig 1) these #entries from analysis of 200K events (~20% of
the run) and the T/B ratios were
L-arm top(T) 2336, L-arm bottom(B) 2795. T/B = 0.836
R-arm top(T) 2884, R-arm bottom(B) 2817, T/B = 1.023
Run 2233 (Y = +1 mm) results :
L-arm T 2630 L-arm B 2742 T/B = 0.959
R-arm T 2980 R-arm B 2818 T/B = 1.057
Note, increasing Y by 1 mm increased T/B by a few percent, but this
could be a purely geometric effect (possibly ambiguous), however
I think T/B would have decreased if there was a blockage.
But this is still pretty crude and I need to do cuts on Y & Z
target, bigger Y changes, etc. Later...
Note, we can also get crude info on occlusion from looking at scaler
rates. I used the Podd scaler analysis package to obtain rates.
It is important to normalize to beam current since this drifted
with time. I pick "u3" for the current. Doing that I get for
Run 2232 in arb. units
T1/u3 = 170
T2/u3 = 26.8
T3/u3 = 162
T4/u3 = 55.0
Run 2233 (Y = +1 mm)
T1/u3 = 170
T2/u3 = 27.0
T3/u3 = 162.2
T4/u3 = 54.1
So, the trigger rates normalized to beam current didn't change.
Waiting for beam... want to make bigger Y changes and some X ....