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Archived Messages for HALLA_MIN_1997@cebaf.gov: Minutes
Minutes
John LeRose (lerose@CEBAF.GOV)
Fri, 14 Mar 1997 12:59:31 -0500
Minutes of Hall A Group Meeting 11 March 1997
1 Announcements: (Kees de Jager)
1.1 Beamtime requests for final scheduling in the
second half of this year and preliminary
scheduling in the first half of next year are
in (the deadline has passed). Scheduling
committee meets Thursday (13 March).
1.2 Re hall access during runs in more than one
hall: Accelerator doesn’t have schedule a
sufficient number of people on each shift to
perform searches and keep the accelerator on at
the same time. One solution is to hire more
people (too costly). The adopted solution is to
arrange shifts such that someone with ARM
training can be in the counting house at all
times. All staff members will take ARM training
starting 1 April.
2 Engineering and installation: (Ed Folts)
2.1 Working on automated collimators. Won’t be
ready this week.
2.2 Working on waterfall target interlock.
2.3 Large window installed on target chamber.
Testing.
2.4 Researching turbopump for Møller Polarimeter.
2.5 Measurements of e-arm position completed.
2.6 Lockup time is noon on Thursday (13 March)
3 Commissioning:
3.1 Juncai Gao gives report on preliminary analysis
of coincidence commissioning data
3.1.1 Raw coincidence timing FWHM 6 nsec.
3.1.2 indications that some Scintillators don’t
have correct timing offsets
3.1.3 Preliminary missing mass and missing
momentum spectra look OK.
3.1.4 Angular correlations look OK.
3.2 Nilange Liyanage shows results of preliminary
study of coincidence efficiency studies.
3.3 In general everything looks good. No serious
problems.
3.4 Coincidence Hardware/Software: (Bob Michaels)
3.4.1 ESPACE: installing changes requested by
various people. Will make new release when
completed.
3.4.2 Still have a problem with cabling between
spectrometers. Rerouting cables to make
them their absolute minimum length should
solve this.
3.5 Fire alarm in Hall A last Saturday night points
out need for better defined rules and
procedures. Problems included:
3.5.1 Failure to properly reset fire alarm.
3.5.2 Gas didn’t shut off as it was supposed to.
(Howard Fenker reports that everything is
OK on our end.)
3.6 Last weekend’s run ended early because of
large LCW loss in Hall C.
3.7 Paul Rutt (run coordinator) reviews plans and
objectives for this weekend’s FPP commissioning
run (13-17 March).
3.7.1 Main objectives:
3.7.1.1 Alignment of chambers
3.7.1.2 Determine scattering fraction in
Carbon analyzer.
3.7.2 Kinematics chosen to give uniform
illumination of chambers. (Waterfall
target with pmissing=100 MeV/c)
3.7.3 Discussion of chamber alignment tolerances
and objectives.
3.8 Riad says he needs more volunteers to sit
shifts.
3.9 Discussion of need for Al. panels after VDC’s.
Can they be removed? To be decided later when
questions can be answered quantitatively.
3.10 Maximum current will be 25 microamps.
4 Beamline: (Arun Saha)
4.1 Trying to find a supplier for Be. plating on
target windows.
4.2 BCM calibration procedure has been developed
and will be posted in the counting house.
5 Waterfall Target and Data Analysis: (Meihua “Meme”
Liang)
5.1 New control box in the counting house to
control the pump for the waterfall. Allows
emergency shutoff. Shutoff in the Hall is still
available.
5.2 Working on Hadron Arm optics. Estimate 2 weeks
to complete.
5.3 Learning survey techniques for determining
spectrometer positions.
5.3.1 Working on data processing
5.3.2 MIT Post-Doc has agreed to do part of the
work on alignment software.
6 Cryotarget: (Jian-Ping Chen)
6.1 Finished piping in top of cryocan
6.2 Target lifted onto support.
6.3 Upstream windows:
6.3.1 Tried machining 3 with lower grade Al.
Only one passed pressure testing.
6.3.2 Going back to stronger Al.
6.4 Lifting mechanism control box tested in Hall C.
OK!
6.5 Gas Panel should be finished by Friday
(14 March)
7 Detectors: (Bogdan Wojtsekhowski)
7.1 Problem with High Voltage mainframe failure.
7.1.1 Temporary solution in place.
7.1.2 Discussing with LeCroy
7.2 Working on getting shower counters all
connected
7.3 Aerogel still has problem with 3-5 cm sagging.
Need a new person from U. Regina to work on it.
7.4 Question re calibration of gas Cerenkov. Saclay
people have gone to Mainz for an experiment. No
new results. (" may be some results will be
next week " - B.W.)
8 Ops Manual and Møller Polarimeter: (Sirish Nanda)
8.1 Ops manual first draft nearly ready. List
circulated with outstanding parts and people
responsible. In general looks good.
8.2 Møller:
8.2.1 Dipole and Detector stand are under
contract.
8.2.2 Shielding box design underway.
8.2.3 U.Ky. have taken delivery of the shielding
insertion.
8.2.4 U.Ky. working on widening dipole gap.
Awaiting receipt of shim pieces from JLab.
Should have them next week.
8.2.5 Talked with Danfysik re power supplies.
Now expect delivery of first power supply
in mid-April and the second in mid-May.
9 Fast Raster: (Bob Michaels)
9.1 Bench assembly nearly completed.
9.2 We have made no progress on electronics. Will
require about three man-weeks of work. Who can
we put on it?
10 Controls: (Javier Gomez)
10.1 Writing Ops manual contributions
10.2 Design completed on collimator encoder and
drive.
10.3 Trying to get DAC’s for Q2/3’s
10.4 James Proffitt reports:
10.4.1 Circuit for interface between waterfall
target and FSD is completed and bench
tested. Maybe ready for this weeks run.
10.4.2 Will require 2 more days to finish the
first interlock board for collimator.
Automated collimator motion may be
available on one arm by the end of next
week.
11 Magnet Monitoring and Measurement: (John LeRose)
11.1 Learning survey techniques. Warns that we
amateurs won’t be as fast as the professionals.
11.2 Problem during run with NMR’s on Electron arm
appears to be and electrical problem with the
gradient compensating coils. Will investigate
further tomorrow (12 March). Also, electronics
seem to be much quieter when there’s no beam in
the hall. Don’t know why.
11.3 Asks for better logging of problems when they
occur during a run. Note in the logbook
characteristics of problem, actions taken,
parameters varied and by how much, etc.
12 Parity meeting scheduled for Friday and Saturday(14-
15 March)
13 Theory Group will be moving to trailer city which
will hopefully free up some space in CEBAF-Center.
-JJL