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01/31/2002
Target lab status:
-
Work finished: (Vince and Patricia)
-Sergei ruptured on Monday, around 2:30pm, for details,
please read tlog entry #213
;
-Adjust oven PID control;
-25 cm reference cell (used during A1n) was sent to RadCon,
prepare for wall thickness measurement at UVa;
-
List to do:
-Patricia will continue working on PID settings of oven
controller, Kevin suggested doing adjustment with cell in, and try "auto
PID" option;
-Vince will do RF calibration on friday, then do water
calibration during weekend; He is also working on fit programs;
-Next week, put one cell (possible options: Queen Mary/Sally/Brunhilder/?King
William), start fiber optics setup for EPR;
g2n Analysis:
(Kevin)
-
Did acceptance cut dependence study
for kinematics #1 and #2, very small effect on parallel asymmetries,
~<1 sigma effect on perpendicular asymmetries. All effects look
like statistical fluctuation;
A1n Analysis:
(Xiaochao)
-
Work completed:
-x-section: left arm data <
MC, right arm data > MC;
-Subtract N2 dilution from refcell
3he runs, now pressure curve looks very reasonable (very small offset at
zero pressure); Polarized He3 production elastic run vs. pressure curve:
left arm - very close; right arm: pol3he higher than curve;
-Use Gore wall thickness data from
UVa, but this did not solve the difference between two arms;
-Use reference cell wall thickness
data from Vince (EEL) for ref cell runs;
-Due to the descrepancy between
MC and data on right arm, large phi_target part (0.02<phi_targ<0.03),
did several studies trying to pin down the problem:
-
check target var histograms, shower/preshower
distribution - did not find anything abnormal;
-
do elastic analysis with small targ_phi
cut, change cut from abs(phi)<0.03 to abs(phi)<0.02; now x-section:
left arm data < MC, right arm data = MC (almost);
-
But from pressure curve, left arm is
good, right arm, pol3he run is still higher than curve;
-Found result is very senstitive to
wall thickness, need to check it more;
-
List to do:
-check W3he cut dependence;
-check deadtime correction (using
T3accpt, T4accpt from data);
01/24/2002
Target lab status:
-
Work finished: (Vince)
Sergei lifetime analysis.
Temperature test analysis;
Oven controller;
-
Result:
Sergei lifetime (AFP loss corrected) is 33.97 hours;
A bug in temperature test analysis is fixed, calibration
constant for Sergei is 3.95mV/%, gives maximum NMR~48% (EPR ~ 45% using
new temperatures);
Oven: Now it takes ~ 30 minutes to stablized to +/- 1
degree;
-
List to do:
Vince will adjust PID parameter settings in oven controller;
Wall thickness measurement for Sergei, then Sergei will
be sent back to W&M;
Start fiber optics setup (purchase fiber coupler etc..);
-
Core people need to sit down and
discuss a long-range plan for target lab work.
g2n Analysis:
(Kevin)
-
Did pid cut dependence study for kinematics
#1 and #2, almost no dependence has been observed;
-
List to do:
Continue pid cut study for other
kinematics;
Start acceptance cut dependence
study;
Target Analysis:
(Kevin)
-
Study of water calibration with different
lock-in phase;
A1n Analysis:
(Xiaochao)
-
BPM correction for elastic analysis:
Beam position offsets and radius have been extracted
for commissioning runs, will be used as an input to espace;
Before full BPM correction through espace, effect
of BPM has been estimated by adding beam position offset in MC simulation.
For a typical beam offset, acceptance changed by 2% on left arm and 1%
on right arm, x-section changed by 1E-3;
Full BPM correction in espace is possible (need help
from Bodo), and necessary. It is also possible to add window in ev_time
so correction can be done even if there is a large shift during one run.
-
Pressure curve:
N2 and He3 pressure curve (xsection*density
vs. density) - both have positive offset at zero pressure.
Polarized He3 production elastic
run is significantly higher than He3 pressure curve;
-
List to do:
check ref. cell wall thickness
and add it to MC;
check Gore wall thickness on left/right
sides;
01/17/2002
Target lab status:
-
Work finished: (Vince)
Did 2nd Sergei lifetime measurement;
Did 2nd temperature test analysis;
Oven controller;
-
Result:
Sergei lifetime (AFP loss NOT corrected) is 33 hours;
It takes ~ 1 hour for oven to stablize whenever lasers
are turned on/off, not good enough for a reliable temperature test;
-
List to do:
Vince will try to fix the oven;
A1n Analysis: (Xiaochao)
-
BPM correction for elastic analysis:
Beam position dependence is observed in elastic analysis;
Need to check if event-by-event bpm correction is necessary. In the
worst case need to run espace two times to do event-by-event correction.
g2n Analysis: (Kevin)
-
Empty ref cell run analysis, try to
remove window through histogram subtraction of pol3he runs and empty cell
runs.
01/10/2002
Target Lab Status:
-
Work finished: (Vince, Patricia,
Jindong)
During holiday,
Jindong did spin-up, spin-down and temperature test for Sergei; Maximum
is about 35% (NMR & EPR);
After
holiday, it has been found that cell position is pretty low (~5mm lower
than central position of oven), so part of laser power is not hiting the
cell. On 01/05/2002, Sergei re-installed, laser alignment has been
checked;
Did 2nd
spin-up and spin-down for Sergei;
Sergei
lifetime 36 hours (AFP loss not corrected);
Sergei maximum ~48% (NMR), ~45% (EPR);
Temerature test result is not reliable due to oven problem;
A1n Analysis: (Xiaochao)
Change beam
energy from 1.19733 (MBSY1C) to 1.19638 (Tiefenbach) GeV, which improve
the W and target_dp (consistency between data and MC) a little;
Fixed
a bug in left arm MC code, (about beam x);
Add HRS
angle from survey to simulation and data;
Change
event generation of beam x&y in MC code, makes it to be a uniformly
distributed circle;
Cross
section: left arm data is ~5% < simulation, right arm very close;
Discrepancy
of target_dp and W, between data and MC, still exist, might be due to error
in beam energy and HRS central momentum;
g2n Analysis: (Kevin)
-
BPM info cannot be put into CWN files,
need to modify espace source code; Apparently Nilanga doesn't have time
to do it;