RC Summary
Monday 09-25-2006 Swing through
Tuesday 09-26-2006 Day
Current Status
- Quite nice beam.
- 6.80 Coul for IHWP OUT, 1.16 Coul for IHWP IN
- LH2 target is in.
- IHWP is IN.
- Detectors are on.
Achievements and events
- A very respectable amount of production data on LH2 has been
acquired.
With 30% of our time used (31.6 days), we have collected 11.4% of
the possible 219 Coul.
For fall running (4.6 days so far), we have collected 8 Coul
which means we are running
at a "macroscopic efficiency" of 33.5%. Recently, this number
has been quite a bit higher.
- A Moller polarization measurement was carried out. The Moller
performed well, and tuning was
not particularly painful. Polarization was found to be 85-86%
with a 2-3% systematic error
as compared to the Mott measurement of 80-82%. Additional more
complete analysis may reduce
the differenct between these two measurements (though
traditionally, the Moller is 1.5% higher
than the Mott).
1229
15)
- The IHWP was moved IN during the Moller measurement.
- The Exec. Committee met today to solve the problem of empty shift
slots.
Plans
During the next few shifts we will perform the following additional
tests:
- During the day shift around 9:30 AM, we will devote an hour to
an arc measurement of the beam energy.
- For a brief period on Wednesday we will turn down the beam
current to about 100 nA and attempt to turn on the
HV for the HKS drift chamber which is not installed at the
moment.
We have accumulated quite a bit of data with the IHWP OUT. So for, for
a while, we will follow a cycle of: 2 days
IN, 1 day OUT, 2 days IN, 1 day OUT. When the charge is better
balanced, we change the IHWP every day at the start
of the day shift.
We will concentrate on Production, Production,
Production.
Concerns and Their Resolution
- A new "Omega" temperature controller will be installed on
Monday 10/2 in an effort to fix the intermittent
loss of lock of the chassis.
- There is still a dead cell in the coincidence matrix. If a
replacement of the appropriate cable
does not fix this, we may consider not doing anything further
(living with the dead channel)
because it is in the superelastic region where we get very few
counts (but is this true for LD2?)
- We have no confirmation that the new PMTs were in fact shipped -
- they have certainly not yet arrived.
- We have discussed two options for checking the correction of
rate-related effects: running
for an extended period at lower current (30 µA) or doing
a Wells plot. A day of running at
30 µA would give us about 34 ppm uncertainty in our
asymmetry. A shift of running for a
Wells plot would permit a check at the few percent level. We
should probably consider doing this
kind of check -- though it will reduce our Coulomb count ☺
Shift Summaries
Swin
g
Owl<
/A>
Day<
/A>