Hi,
at the bottum of this email, are parts of the k factor calibration I
generated on run 4213-4228 (last few H2 unpol runs last year) and run
705-709. the program to generate these numbers is dst_kfac.C and is
checked into BlastLib2. it can be applied to any runs with dst file
available, but the results will ofcourse depend on the t0 calibration used
to crunch the runs.
the three attached figures pretty much shows what the script does.
cell-width.ps is a map of hit positions along one wire plane. the scipt
generates 6 such canvases, one for each chamber. tdc.ps is the tdc
distribution per wire for one superlayer. it is different from Doug's in
tha these include only hits fitted into tracks. kfac.ps is K factor by
cell number. for 6 super layer.
This is how to read the numbers listed below:
on the left is cell number ofcourse, then is the t0 obtained by locating
the right most bin in tdc spectra used in tracks, then t0_d is the value
of t0 Doug sent the week before. then is the difference between the two
and the final colume is the k factor.
a few thing to remind you when interpreting these numbers:
the data were crunched with Doug's new t0 calib, i.e. t0_d, so t0 can not
be any larger than t0_d and is not independent of t0_d. the scale is 20
channels = 10 ns ~= 200 um.
k factor is universally less than 1 for these runs. very often more than
10% away from 1. I think TB is right saying the catch Doug mentioned could
not possibly be a 7mm effect,
if t0 is too large, it will leave a gap in X_drift at the center of the
cell and in turn shift the "reconstructed" half cells out and cause a
wider cell. but again, 40 channels ~= 0.4mm, not enough to account for a
10% wider cell.
cell number t0 t0_d t0-t0_d k
0 0 0 0 0 6413.75 6427.1 -13.3501 0.829787
0 0 0 1 0 6406.25 6436.6 -42.8501 0.928571
0 0 0 2 0 6426.25 6429.8 -21.0498 0.886364
0 0 0 0 1 6393.75 6462.3 -43.5498 0.915493
0 0 0 1 1 6403.75 6458.2 -49.4502 0.942029
0 0 0 2 1 6396.25 6467.6 -43.8501 0.942029
0 0 0 0 2 6408.75 6442.8 -21.5498 0.886363
0 0 0 1 2 6388.75 6437.6 - 3.8501 0.894495
0 0 0 2 2 6393.75 6434.2 - 2.9502 0.906977
0 0 0 0 3 6418.75 6473.5 -27.25 0.886363
0 0 0 1 3 6403.75 6435.7 0.549805 0.882353
0 0 0 2 3 6411.25 6475.1 -43.8501 0.886364
0 0 0 0 4 6408.75 6436.2 -12.4502 0.955882
0 0 0 1 4 6396.25 6439.3 -5.5498 0.951219
0 0 0 2 4 6408.75 6458.7 -7.4502 0.878378
0 0 0 0 5 6423.75 6436.3 -5.0498 0.902778
0 0 0 1 5 6421.25 6448.3 -27.9502 0.924171
0 0 0 2 5 6433.75 6438.7 -9.9502 0.855263
0 0 0 0 6 6421.25 6444.7 -38.4502 0.911215
0 0 0 1 6 6426.25 6453.7 -49.9502 0.906977
0 0 0 2 6 6436.25 6417 -28.25 0.890411
0 0 0 0 7 6433.75 6436.5 -32.75 0.965347
0 0 0 1 7 6418.75 6429.1 -32.8501 0.9375
0 0 0 2 7 6421.25 6465.2 -43.9502 0.870536
and for run 705-710:
difference between the two t0's are larger, so this new set of calibration
may not be the correct one for those runs. (new resister chain?, reversed
field? lowered threshold?). in fact resolution of the new crunch is worse
than the old(40MeV)
k factors are much closer to 1 thise time. if you see 1, please interpret
it as an indication that statistics are not sufficient to determine a cell
width rather than declaring vicotry about calibration.
0 0 0 0 0 6376.25 6427.1 -50.8501 1
0 0 0 1 0 6363.75 6444.7 -80.9502 1
0 0 0 2 0 6356.25 6449.9 -93.6499 1
0 0 0 0 1 6381.25 6436.6 -55.3501 1
0 0 0 1 1 6326.25 6453.7 -127.45 1
0 0 0 2 1 6363.75 6428.5 -64.75 1
0 0 0 0 2 6366.25 6429.8 -63.5498 1
0 0 0 1 2 6343.75 6417 -73.25 1
0 0 0 2 2 6343.75 6425.2 -81.4502 1
0 0 0 0 3 6368.75 6462.3 -93.5498 1
0 0 0 1 3 6366.25 6436.5 -70.25 1
0 0 0 2 3 6351.25 6428 -76.75 1
0 0 0 0 4 6443.75 6458.2 -14.4502 1
0 0 0 1 4 6508.75 6429.1 79.6499 1
0 0 0 2 4 6411.25 6436.2 -24.9502 1
0 0 0 0 5 6443.75 6467.6 -23.8501 1
0 0 0 1 5 6398.75 6465.2 -66.4502 1
0 0 0 2 5 6386.25 6437.6 -51.3501 1
0 0 0 0 6 6406.25 6442.8 -36.5498 1
0 0 0 1 6 6356.25 6455.4 -99.1499 1
0 0 0 2 6 6433.75 6429.1 4.6499 1
0 0 0 0 7 6383.75 6437.6 -53.8501 0.975
0 0 0 1 7 6368.75 6438.3 -69.5498 0.984849
0 0 0 2 7 6388.75 6428.1 -39.3501 1
0 0 0 0 8 6423.75 6434.2 -10.4502 0.970149
0 0 0 1 8 6446.25 6437.9 8.3501 0.95122
0 0 0 2 8 6413.75 6436.9 -23.1499 1
0 0 0 0 9 6401.25 6473.5 -72.25 0.946602
0 0 0 1 9 6418.75 6445.3 -26.5498 0.9375
0 0 0 2 9 6398.75 6438.1 -39.3501 0.924171
0 0 0 0 10 6421.25 6435.7 -14.4502 0.975
0 0 0 1 10 6403.75 6456.8 -53.0498 0.942029
0 0 0 2 10 6408.75 6439.2 -30.4502 0.928571
0 0 0 0 11 6411.25 6475.1 -63.8501 0.942029
0 0 0 1 11 6436.25 6428.6 7.6499 0.942029
0 0 0 2 11 6413.75 6436.9 -23.1499 0.924171
0 0 0 0 12 6421.25 6436.2 -14.9502 0.946602
0 0 0 1 12 6416.25 6436.2 -19.9502 0.946602
0 0 0 2 12 6393.75 6436.7 -42.9502 0.960591
0 0 0 0 13 6416.25 6439.3 -23.0498 0.933014
0 0 0 1 13 6408.75 6437.3 -28.5498 0.951219
0 0 0 2 13 6418.75 6438.5 -19.75 0.92417
0 0 0 0 14 6401.25 6458.7 -57.4502 0.946602
0 0 0 1 14 6408.75 6459.7 -50.9502 0.9375
0 0 0 2 14 6413.75 6445 -31.25 0.911215
0 0 0 0 15 6408.75 6436.3 -27.5498 0.955882
0 0 0 1 15 6406.25 6448.6 -42.3501 0.942029
0 0 0 2 15 6396.25 6452.7 -56.4502 0.894496
Chi
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