Results from the Straws
Cosmic Time Profile Study
August 22, 1996
This plot was made from about 4 hours worth of cosmic ray data. I used
the OH counters as the trigger, and as the timing strobe. Because of
OH's close proximity to St2, this trigger proved to be an effective
cosmic trigger. Aproximatly 1.3 million OH events were used to make this
plot, so it's not efficient, but it works. The time information, in
nanoseconds, from all wires in St2 (484 minus 15 or so
extreamly hot channels) went into this plot.
Although I am reluctant to draw too many conclusions from this data a
few things are clear:
- The events fall inside the TDC window,
- The maximum drift time is of the expected order (40-60ns), and
- The straws will work!
From the same dataset a similar time profile was produced for St1. The
statistics are much smaller because of the decresed rate of cosmic
coincdence with OH (about 10 feet separate the two detectors in Z).
This physical separation creates a time profile that is not as sharp.
Still we get a reasonable time profile (shown below).
Jon Link, link@ucdhep.ucdavis.edu