there is a problem with TTL9B, as can be seen in the above plot of
coplanarity peak versus timing peak for coincident events in L9,R9 (or
R8 or R10). ideally this should be a point, since both variables are
peaks. however, if the bottom tof TDC has problems then it will be a
line of slope -1, and if the top tof TDC has problems it would be a line
of slope +1.
i looked at the length of the line as a function of TTL9B to see if
the problem could be calibrated away, and was able to decrease the
length from 35 channels to 25, by assuming fitting for the TDC
calibration of 31 ps/channel instead of the usual 50. but it is still
much worse than the width (7 channels). the timing resolution is 3
times worse for this paddle.
therefore, i believe there is some problem with the discriminator.
you can also see that the problem only affects the electrons, because
the proton peaks look fine (they have higher adc's). so maybe the
problem can be fixed by raising the voltage to the phototube. this
problem goes way back to at least last december.
note: you can also see that tube counts much lower than the others:
369 compared to 1514 on the top
--chris
ltt ltb ltc rtt rtb rtc
0 3337, 3736, 2866, 5237, 3567, 3357
1 4118, 3046, 2813, 3107, 3213, 2448
2 2849, 2541, 2193, 3035, 2618, 2257
3 2307, 2444, 1793, 1188, 1786, 1107
4 2805, 3123, 2022, 3209, 2314, 1980
5 2469, 564, 561, 1767, 1369, 1137
6 1391, 2132, 1199, 1366, 2081, 1166
7 1885, 1479, 1099, 1509, 1267, 972
8 1391, 1800, 1039, 1671, 732, 695
9>>> 1514, 369, 367, <<<< 1042, 980, 681
10 1607, 1636, 974, 663, 975, 548
11 2875, 3621, 1904, 1909, 3069, 1248
12 1878, 2594, 1232, 987, 2706, 854
13 1825, 1447, 867, 2141, 2002, 1045
14 2426, 1721, 665, 1436, 2684, 1056
15 2192, 2790, 1210, 2305, 563, 530
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:32 EST