Patricia Solvignon
reported on target analysis:
Due to the
large difference in lifetime measurements at UVa and JLab, the
AFP loss correction to the lifetime
measurement was studied. Patricia used
three methods to correct the lifetime:
multiple spin-down, correction point by
point, and applying an equation provided
by Alexandre Deur. The three methods
give comparable results, but the third
tends to give slightly different lifetimes.
For the ice
cone cells, Steffen Jensen's method isn't valid for non-symmetric cells.
Patricia used a lorentizian for the
RTD's, which fits the data very well.
Patricia presented
the cell performance results for various cells tested in the past
couple months
Vincent Sulkosky
discussed the target lab status:
New equipment
for the target system includes a computer, spectrum analyzer,
and gaussmeter probe. Modifications
to the target system have been completed and
tested with everything checking out
fine.
Calibration
tests have been performed using the new ice cone cell design. Water
calibrations and Q-curve gains check
out with the movement of the pick-up coils
upstream. Due to the cell geometry
change, the flux code was changed to
accommodate the changes. Flux
model tests with the new code are reasonable, but
the collaboration would like more
tests to check for geometry dependence.
The new EPR
coupler system works well after some modifications to the mounting
design due to interferences in the
reference cell position with the fiber. One location
will work for the spectrum analyzer
in both longitudinal and transverse.
NMR Results
were reported on various cells tested recently. Both NMR and EPR
polarimetries agree to within about
2% for recent tests.
Alexandre
Deur gave an update on the cell status for E97-110:
At UVa over
a dozen cells have been made but there has only been three marginal
cells and 2 good cells produced.
But one of the good cells Victor blew up. At W&M
no good ice cone cells produced, but
tests are under way to understand why. Reasons
for the low success rate are the complicated
cell design and how much the glass has
been worked. Cells that have
had less work have had better lifetimes and polarization.
Next week ice
cone reference cells will be produced by both Mike and Willie.
Alexandre wants to produce good c1720
standard cells with thinner walls.
Todd Averett
gave an update of the W&M target system:
After filling
two standard 40 cm cells this spring (Patrick and Harry), Todd found a
vacuum leak, which explained their
low lifetimes. But since then two Ice cone cells
have been filled with only ~ 3 hour
lifetimes. It is now believed that part of the problem
is the glass blowers over worked the
glass. Todd has filled 4 spherical cells to test his
system. Initial results look
promising.
Jaideep Singh
discussed the target lab status at UVa:
UVa will continue
to do cell lifetime and polarization measurements. EPR system
ready. Plan to study AFP loss
and EPR. For cell characterization, the Ti-Sapph laser
is being repaired.
Jaideep looked
into the cell lifetime difference between JLab and UVa. Possible
extra relaxation mechanism found at
JLab with a rate of ~ 1/60 hours. The extra rate
agrees well with the lifetimes measured
at JLab.
Discussion
on target moving/installation and other issues:
For field direction, Alexandre Deur will check into how much a vertical
angle effects physics for the experiment.
Documentation needed for the experiment
includes: Run Plan, COO, ESAD,
OSP, RSAD. Run sheets and shift checklist are
also needed. Tasks and coordination
responsibilities were discussed. Those that will
be aiding during the installation
and experiment should make sure their training is
current. Training includes:
RAD II, LOTO, Laser Safety, target operator, and
compton.