Muon Slides 10-October-2001
- I am still working on the digitization.
- I use the following command file to find
the efficiencies for rear tracks. The result is
this set of plots.
- When I look at TSU times versus the track stub t0, I
find no evidence for TSU
hits behind track stubs. I'd expect to see some bunches, as
we do for the BSU.
We can see
a curious early peak at about 45 nsec, but not much else.
This does not mean there are none at all, but in 86,000 BMU
stubs I didn't find enough to see. For a brief review of the
statistics for the run, see this.
Several stacks had crosstalk, and had to be eliminated. Upper left
is all but those, upper right requires a BSU hit, and the bottom
are subsets requiring front or rear BSU hits.
- However notice that when I compare TSU to
front BSU times I do find a fairly
strong correlation, although not with a lot of statistics. There
are also correlations with rear BSU times, which are
compared here. I do not understand
the timings, however. The preliminary BSU peak is at about 115 nsec,
and the interaction peak at about 180 nsec. However when comparing
the front BSU with TSU, the TSU times are around 140 and the BSU times
are around 135--both of which lie between the two understood peaks.
The rear BSU comparison shows a cluster at TSU-time of 40 nsec and
BSU-time of about 180 nsec. This would seem to suggest that the TSU
t0 is 140 nsec lower than that for the BSU, but that can't be right,
in view of this plot, which
shows what look like interaction peaks (or perhaps combinations
of interaction and precursor) at 175 (and perhaps a broad peak at 220).
- I am informed that on the east side the voltages for front
BSU paddles and rear BSU paddles were interchanged. That probably
explains the greated number of inefficient cells on the East side.
It does not explain why I get fewer BMU stubs on the East.
- I don't understand what is going on with stacks 174, 176, and 177
(all on the West). When I look at the time difference between subsequent
hits in the same cell (2 or more hits) I see a
spike at about the bunch crossing time separation. I also see a bump
at about the place I expect for crosstalk. I have a more detailed
plot with a breakdown by layer here. The
inner layers show most of the early time peaks, but all have the late
spike. George says that there was a nasty cabling problem, and
that these cells had garbage.
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