MINUTES ANALYSIS MEETING 2/11/03
=================================
Present: TB, DH, TL, JS, CC, KD, BC
TB: attempts to correlate Wch S/N with tof/scalers analysis do not
show a clear signature. Difficult to distinguish charging effect
from a deterioration of beam quality. Usable data had taken w/
restricted trigger, no measure of true/randoms ratio in L0-R0
can be seen. S/N does not seem to correlate with scaler rates,
although it seems to scale with lifetime
There are some ambiguites in the MC and assupmtions related to eloss:
the Al storage cell and chamber exit foil (steel) were not included in
recent calculations. Also, the CC covers are 1+1 mm of Al on each side
and the CC aerogel density = 0.1-0.3 gr/cm3 (?) is important to few MeV.
On other hand, effect of impact angles (+- 20 deg) is small.
Using 1/8+1/8 plexiglass covers (no Pb foils) I get
PROTON Tp> 54.2 MeV theta_e>22.4 deg sigma<3.2 ub/sr
DEUTERON Tp> 73.0 MeV theta_e>37.5 deg sigma<0.003 ub/sr
so we may only have a few elastic e-d, difficult to see.
CC: shows behaviour of # of left/right wire hits for good/bad runs. Single
tracks seem to come with a lot of noise hits (50 hits on left, 25 on right)
Suspects e-map causing problems with the stubs. Will provide a list
that can be checked by hand.
JS: updated Xsection plot with correct target thickness (result is slightly
worse)
Wire chambers: long discussion. Not everybody using same t0, and time-position
relations. DH has < 300 um res, sufficient for tracking, before
B-dependent corrections (lorentz angle)
TL improving recon algorithms, many good tracks still not
recognized. Submitting garfield calculations (takes 2 weeks)
PLANS:
Wch still top of the list. CC will join effort with recon. Plans to use more
tof info (x-y position and which gave trigger, f.i.) on input. Also, t0
should be corrected for proton tracks (slower). Progress on tracking should
be made before next round of corrections in a cell (t0, drift, offset).
Need to revisit how tracking energy loss correction is done.
TB wants to look into MC eloss first.
-- ________________________________________________________________________________ Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124 research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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