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Archived Messages for HALLA_MIN_1997@cebaf.gov: Minutes
Minutes
John LeRose (lerose@CEBAF.GOV)
Mon, 24 Feb 1997 15:08:49 -0500
Minutes of Hall A Group Meeting 18 February 1997
1 Remarks re last week’s minutes? None.
2 Meeting 16O FPP tomorrow (19 February) at 13:30 room
B207. All are welcome.
3 Report on last weekend’s running in the Hall.
3.1 Arun Saha reports on beam activities:
3.1.1 Tuning to hall went OK.
3.1.2 Ion Chambers worked as expected (trip off
when beam is missteered)
3.1.3 High power beam: Trying for 4 GeV and
200 microamps. Saw maximum current of
161 microamps with maximum stable current
of 154 microamps. Will try again tonight
for 200 microamps.
3.1.4 Saw very little radiation in the hall,
indicating very good optics.
3.2 Pascal Vernin reports on wire scanner studies.
3.2.1 Software worked very well
3.2.2 Some hardware problems (electronic noise,
beam motion, etc.)
3.2.3 Overall results are very encouraging.
4 Hall Status: (Kees de Jager for Ed Folts)
4.1 Hadron arm completely cold
4.2 Q3 control problem is fixed.
4.3 Working on Dipole power supply regulator.
4.4 Having a problem mounting the exit foil on the
scattering chamber. Working on it.
5 Magnet measuring and monitoring: (John LeRose)
5.1 Waiting to make some measurements on the Hadron
dipole to verify stability.
5.1.1 It appears from cursory measurements made
at 1100 Amps that the very long lifetime
(8 hours) settling of the magnetic field
no longer is there. (Field was very stable
for half an hour after 2 hours at
1100 Amps.) Suspect observed long time
constant settling back in December was due
to power supply drift.
5.2 Added smoothing routine to field map analysis
for Electron dipole. Made no significant
difference in extracted field parameters. EFB’s
move around at the 10 micron level.
5.3 Expect Guido Urciuoli to arrive from Italy on
20 February. Will work on data analysis of
Hadron arm commissioning.
6 DAQ: (Bob Michaels)
6.1 Setting up Hadron arm with Bogdan and Meme.
6.2 We are now using ADACH1 for CODA. Please
communicate any problems to Bob.
6.3 Will need to shut down electron arm for several
days in order to implement electronics for
coincidences. Will keep Electron arm
operational through this weekend’s run and
start the work on Monday.
6.4 Information on beam parameters and magnets are
now in the data stream. Need a volunteer to
check data of commissioning runs to make sure
everything is OK.
7 Beamline: (Arun Saha)
7.1 Having discussions with plant engineering re
placing 9th dipole in building 98.
7.2 Re new waterfall target: now looks good to
install in early April. Will have to coordinate
with other activities in that timeframe.
8 Detectors: (Bogdan Wojtsekhowski)
8.1 Reports on cosmics tests over the weekend:
8.1.1 Wire chambers look OK.
8.1.1.1 Still need to position them (and
the detector frame) carefully.
Chambers are about 5” off.
8.1.2 S1 and S2 are running well.
8.1.2.1 Need to adjust high voltage
8.1.2.2 Need to fix light leak.
8.2 Gas Cerenkov isn’t yet connected. Will require
a few hours.
8.3 Aerogels have a problem with support frame.
8.4 FPP will be in the data stream for the weekend
runs.
9 Controls: (Javier Gomez)
9.1 Getting parts together for the alignment
system.
10 Hadron Electronics and Waterfall: (Meihua “Meme”
Liang)
10.1 working on trigger for Hadron arm and
coincidence.
10.2 Notes problem with waterfall cabling. Cables
are getting snagged by people working in the
area. (Jack Segal suggest that we need to
protect the cables better) Warns that we should
be careful. We don’t have any spare parts!
11 Cryo Target: (Jian-Ping Chen)
11.1 Cold test completed successfully Riad will
show results next week.
11.2 Gas panel assembly going well.
11.3 Techs working on piping on top of cryo can
11.4 Question re beam test with polarized 3He:
11.4.1 Tied to Hall C T20 installation which is
going well
11.4.2 Preparing TOSP.
11.4.3 Dates not clear. Expect a decision in
early March.
12 Electronics Installation: (Jack Segal)
12.1 Has serious concerns re getting delay lines
needed on electron Arm in place before we’re
ready to do coincidence commissioning. Problem
is time is being taken up by beam in the hall.
Will need about 7 days working 10 hours/day.
Kees will look into freeing up the hall more
often.
13 Møller Polarimeter and OPS manual: (Sirish Nanda)
13.1 Met with Paul Brindza to discuss vacuum pump
needs for the Møller. Conclusion: will require
a turbo pump.
13.2 OPS Manual:
13.2.1 Marti making good progress translating to
LaTex.
13.2.2 Still no response to reminder sent out
last week. (4 missing sections)
13.2.3 CAD drawings being translated to
postscript by Susan Esp.
14 Run Plan for this weekend: (Mohammad Khayat)
14.1 Optics runs identical to Electron arm runs
should take 3-4 shifts.
14.2 Bogdan has requested some additional time for
detector tests.
14.3 Still don’t have remote control of slit box.
(Javier estimates will be ready in 2 weeks)
14.4 Hadron arm is NOT mispointed.
14.5 Discussion about beam current requirements.
14.5.1 5 microamps on 50 mg/cm2 Carbon should be
OK
14.5.2 Will only use waterfall with sieve. No
full aperture runs.
14.5.3 Can go to pulsed beam. (Could be more
stable!)
14.6 Plan to do some empty target runs.
14.7 Riad says shift schedule to go out this
afternoon (18 February)
-JJL