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Upward Downward Muon Led Calibration Summary
A M Hawthorne June 1996
In May 1996, 3 special led calibration runs were performed as described
in a posting by Hunmoo Jeon. These runs were to confirm that MACRO was
sensitive to upward and downward muons for each box pair combination.
Run 90237 contains sm 1 and 2
Run 90240 contains sm 3 and 4
Run 90241 contains sm 5 and 6
Using this data, my velocity calculation code, and the standard calibration
data base, I have computed a beta value for the 27856 events that contained
an led fake box and two scintillator tanks, out of the 45668 events in the
the three calibration runs. Here are the cuts I made.
Run / Total 90237 90240 90241 Combined total
Total events: 20648 11494 13526 45668
Cut 1 (bari): 384 412 384 1180
Remaining: 20264 11082 13142 44488
Cut 2 (no97): 6410 0 4170 10580
Cut 3 (no97): 1096 227 610 1933
total cut 2/3: 7506 227 4780 12513
Remaining: 12758 10855 8362 31975
Cut 4 (nobx): 71 15 0 86
Remaining: 12687 10840 8362 31889
Cut 1 == Events that also contained a fake box n98, bari box
Cut 2 == Events that also contained a fake box n96, N/S fake box
(2 fake boxes and no real boxes were present in these events)
Cut 3 == Events that did not contain a fake box n97, led calibration fake box
(these events did not contain any fake box)
Cut 4 == Events that only contained fake box n97, led calibration fake box
and no real boxes
Remaining: 12687 10840 8362 31889
one box: 274 565 6 845
two box: 12411 10274 8356 31041
3/+ box: 2 1 0 3
Only 2 box events were studied for this summary. One box events can
be explained partially, if not entirely, as being the partner tank for
tanks that have non-functional or poorly functioning leds. Presumably,
events with 3 or more boxes were ones with some stray box that fired.
Bottom and top tanks from sm 1-3 had approximately 175-200 events,
while center tanks from these supermodules had double that, as expected.
Bottom and top tanks from sm 4-6 had approximately 125 events,
while center tanks from these supermodules had double that, as expected.
90237 90240 90241 Combined total
two box: 12411 10274 8356 31041
Cut 5: 140 338 0 478
Cut 6: 1356 910 547 2813
Remaining: 11169 9443 7850 28462
Cut 7: 370 0 236 606
Remaining: 10799 9443 7614 27856
Cut 5: Some boxes had significantly lower numbers of events so were cut
from the two box sample. These boxes were: 1B01, 2T06, 3T02, 4C13, 4T08,
4T17. Box combination 3C02 & 3T01 had about 100 extra events at the end
of sm 3's calibration run, due to a bug which Hunmoo later fixed, so these
events were also eliminated from the two box sample.
Cut 6: Some boxes had clearly bogus beta calculations so were cut from the
two box sample. These boxes were: 1C04, 1C12, 1T17, 2T04, 3T03, 3T10, 3T17,
5T17, 6B12, and 6C12. With the exception of the nT17 boxes, all of these
have a history of problems in the led tdc calibrations.
Cut 7: 1C15, 6B11, and 6B16 also seemed to have a milder version of the
problem seen in cut 6 so were also eliminated from the two box sample.
Of these events approximately half were downward going and half were
upward going. The beta peak around +1 is slightly broader and has a
tail above 1.5 in most supermodules. This is not seen in the symmetric
region below -1. I suspect this is due to the leds not modeling muons
ideally in that the led rise time is not being treated properly with the
timewalk correction and to the timing and position estimates made by
Hunmoo's calibration program.
*I note that sm 4 betas should probably be eliminated from these statistics.
SM 4 BC combinations were dominated by negative betas and SM 4 CT
combinations were dominated by positive betas. This is due to some
problem in the timing.
90237 90240 90241 Combined total
Remaining: 10799 9443 7614 27856
+ beta: 5483 4581* 3810 13874
- beta: 5316 4862* 3804 13982
Average # events per box
sm 1 sm 2 sm 3 sm 4(*) sm 5 sm 6
BC + 6 5 6 4 3 3
BC - 5 6 6 7 4 3
CT + 6 6 6 7 3 3
CT - 5 5 6 5 3 3
These upward and downward events were ordered by box pair as described
by Hunmoo.
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Alice Hawthorne
Dept. of Physics
Indiana University
ahawthor@bigbang.astro.indiana.edu
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