Privacy and Security Notice
Archived Messages for HALLA_MIN_1996@cebaf.gov: Minutes
Minutes
John LeRose (lerose@CEBAF.GOV)
Mon, 25 Nov 1996 14:40:35 -0500
Minutes of Hall A Group Meeting 19 November, 1996
1 Engineering: (Bill Schneider)
1.1 Hadron Arm:
1.1.1 Dipole at 120K and going down. Expect to
be cold next week.
1.1.2 Aligning sieve slits tomorrow
(20 November)
1.1.3 Moving to 16 degrees this week.
1.1.4 Vacuum system going in.
2 Magnet Measuring and Monitoring: (John LeRose)
2.1 Working on installing NMR’s in Hadron Dipole.
2.2 Received memo from Chris Curtis re misalignment
of Q2 electron . Misalignment is only 1 mm
vertically, will only cause a slight shift in
the energy spectrum. Since we’ve done all our
calibrations with it where it is the plan is to
leave it there.
3 Commissioning: (Eddy Offermann)
3.1 Analysis of 845 MeV data on all apertures
nearly complete. y0, phi0, theta0 completed.
Working on delta, should be done by the end of
the week.
3.2 Next:
3.2.1 acceptance studies
3.2.2 Absolute momentum calibration
3.2.3 Comparison to 2.445 GeV to see what
changes.
4 Beamline: (Arun Saha)
4.1 Had meeting with Accelerator re January
shutdown work for Arc energy measurement.
Everything is organized.
4.2 Meeting today (19 November) re MPS system.
4.3 Beam Current Monitoring: Branko reports that
electronic noise is much greater for our setup
as compared to accelerator’s. Suggests we push
on Jean-Claude Denard to find out what’s wrong.
4.4 Pascal Vernin is writing a memo on superharp
measurements in Hall C. Longer report is also
under development.
5 Chamber Gas: (Howard Fenker)
5.1 Just finished verifying interlocks on Hadron
arm. Ready to turn on the gas.
5.2 Review scheduled for next Monday (25 November)
6 DAQ: (Bob Michaels)
6.1 Jack Segal has replaced the TDC chips on the
Hadron Arm.
6.2 Working on detector map
6.3 Question: Where are we as regards running the
two spectrometers independently?
6.3.1 Already can and do.
6.3.2 Working on upgrading details in the Hadron
Arm.
7 Cryotarget: (Jian-Ping Chen)
7.1 Gas platform design almost completed.
7.2 Preliminary design of upstream window
completed.
7.3 M. Petratos (Kent State) has requested design
of a collimator for 145 degree scattering.
Discussion suggests that this is a low priority
for Hall A staff. Kent State has the capacity
to design and build a collimator.
7.4 Pressure tests on 3 He cells:
7.4.1 Solder joint broke at 250 psi.
7.4.2 Want to test to 450 psi
7.4.3 Cells hold to 400 psi. Working on
modification if cell block to improve
joints.
7.5 Software:
7.5.1 Working on lifting mechanism.
7.5.2 New student, Natalie Degrande from
University of Ghent will work with Riad on
temperature sensor calibration.
7.6 Lars Ewell reports on motor controller status.
Need variable frequency power supply to power
pumps. e-m noise problems are much reduced now.
8 Waterfall Target, etc. : (Meihua Liang)
8.1 Hadron arm scalers connected. New configuration
e-mailed to interested parties.
8.2 Waterfall having problems with controls
8.2.1 Improving ethernet connection. Switch to
CEBAF ethernet.
8.2.2 Trying to reproduce problems encountered
last weekend during run. (Computers
crashed when target was moved) Problem may
have been a bad connection from VME to
hard disk.
8.2.3 Steve Wells to check the system out
tomorrow.
8.2.4 Bob Michaels suggest collecting all
observations and writing them up to help
identify the problem.
9 Electronics: (Jack Segal)
9.1 Working on cabling the Hadron Arm
9.2 About 2 days to go before VDC’s are in place
9.3 Should be testing with cosmics by the end of
the week.
10 Detectors: (Bogdan Wojtsekhowski)
10.1 Hadron detector package with FPP successfully
lifted to shielding hut platform last week.
10.2 VDC rails require some adjustment.
10.3 Observed irregular background rates last
weekend. Seemed to have spikes just before beam
loss and just after beam recovery. Need to have
BPM’s in the data stream.
10.4 Results with thick Fe target (5% RL at 5
microamps) encouraging.
10.5 Shower counters: (Herbert Breuer Umd)
10.5.1 Amplifier sum modules installed
10.5.2 Results of weekend run with mistune to
fill the shower counters reviewed. Need
more data at opposite y0 value.
10.6 Bogdan reports on Makis Petratos’ seminar
(deuteron form factors). Suggests planning a
test run with correct beam energy, angle, and
spectrometer settings. Expect same background
with carbon target as with deuterium.
11 Ops Manual and Møller Polarimeter: (Sirish Nanda)
11.1 Draft copy of Manual is in the counting house.
Users should look through and make comments.
11.2 Møller:
11.2.1 Reviewed 3 quad design
11.2.2 acceptance looks good over full range
11.2.3 Powered with in-hand Lakeshore power
supplies.
12 Run Plan: (Eddy Offermann)
12.1 Have finished 2.445 GeV optics studies
12.2 Vacuum problems from last weekend weren’t
really a problem. (B. Schneider)
12.2.1 Larry suggests organizing computerized
reporting of problems. Nobody volunteered.
A “volunteer” will be conscripted.
12.3 Next important step is to go to 4 GeV. Can’t
until after January shutdown.
12.4 Left to do is extended target measurement with
waterfall at 845 MeV (check on reproducibility
of earlier measurements) Needs about three
shifts and can be done in parallel with Hadron
arm commissioning.
12.5 CONCLUSION: Punt this weekend. We have 6 days
in December.
13 FPP report: (Ron Gilman with transparencies by Paul
Rutt)
13.1 Presented overview of development plan.
13.2 parasitic beam tests December and February.
13.3 Dedicated commissioning in March
13.4 Two more people coming to work full time on
site in January.
-JJL