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Archived Messages for HALLA_MIN_1997@cebaf.gov: Minutes
Minutes
John LeRose (lerose@CEBAF.GOV)
Mon, 21 Apr 1997 09:58:40 -0400
Minutes of Hall A Group Meeting 15 April 1997
1 General Announcements: (Kees de Jager)
1.1 Collaboration meeting went well. Compliments to
all contributors.
1.2 Re new accelerator schedule now posted on the
web: there is a new column listing priority.
Implications are the following:
1.2.1 The Hall with priority has the right to
call MCC and ask that beam quality be
improved regardless of impact on other
Halls
1.2.2 The Hall with priority has the right to
enforce scheduled energy changes (only
scheduled energy changes). Energy changes
not in the schedule must be coordinated
with run coordinators from other Halls.
There will be bi-weekly meetings in
Larry’s office to sort out problems.
2 Installation: (Ed Folts)
2.1 EP chamber is closed and ready to go.
2.2 Beam pipe has been leak checked and pumped
down.
2.3 Møller:
2.3.1 Quadrupoles should be finished this
afternoon.
2.3.2 Dipole to be surveyed tonight and
tomorrow.
2.3.3 Water done except for 2 valves. Expect
delivery in 2 weeks.
2.4 Q2 Hadron cooling down, expected to be ready
tomorrow (16 April)
2.5 Electron Dipole down because of control circuit
problem. Repairs underway expect to be back up
this afternoon.
2.6 Spectrometer angular encoders installed.
2.7 Collimators:
2.7.1 Electron arm has noise in its encoder.
Will work on as soon as dipole is back up.
2.7.2 Hadron arm is ready.
3 Run Plan: (Paul Rutt, run coordinator)
3.1 Goals:
3.1.1 H(e,e’p) measuring instrumental asymmetry.
(300 microAmp.hrs)
3.1.2 Pn spin transport studies with 9 inch
carbon analyzer. (2000 microAmp.hrs)
3.1.3 Alignment studies with proton singles.
(400 microAmp.hrs)
3.1.4 Parasitic things:
3.1.4.1 parity
3.1.4.2 EP commissioning
3.1.4.3 Waterfall studies (thickness vs.
pump speed)
3.1.4.4 DAQ/trigger studies (vary current)
3.1.4.5 BCM studies (vary current)
3.1.4.6 Lead glass detector studies (8 hr.)
3.2 Plan to go into controlled access mode
Wednesday afternoon at 1700
3.3 Pierre Bertin gives brief overview of plans for
EP commissioning.
4 Møller Polarimeter: (Sirish Nanda)
4.1 Phase I of installation is complete (Quad’s and
target chamber)
4.2 Working on Quadrupole power.
4.3 Phase II has 2 critical items: vacuum box and
dipole power supply. Both are anticipating one
week delays.
4.3.1 Hope vacuum box will be shipped tomorrow
(16 April)
4.3.2 Contemplating alternate short term
substitutes for dipole power supply
4.4 Will operate on TOSP until July.
4.5 Arun Saha asks if Quadrupoles are officially
part of the Beamline and if all protocols have
been followed with Accelerator. Yes.
5 Beamline: (Arun Saha)
5.1.1 Reports on results of recent radiation
level studies in the Hall. In general Hall
A looks pretty good, especially when
compared to Hall C.
6 Design Group: (Al Gavalya)
6.1 Joyce Miller:
6.1.1 Cryotarget
6.1.2 Septum magnet scattering chamber
6.2 Susan Esp:
6.2.1 Alignment mirror positioning
6.2.2 retainer clips for S2
6.3 Bogdan’s rail extensions are ready
6.4 Working on upgrade to stair access to detector.
Stairs are rated for 300 pound live load. NO
MORE THAN ONE PERSON AT A TIME ON THE STAIRS
until the stairs are improved.
6.5 Have begun modeling scattering chamber for the
septa.
7 Controls: (James Proffitt)
7.1 Q3 Electron now fully under EPICS.
7.1.1 Presently using 12 bit DAC for reference.
Can regulate to 5E-04.
7.1.2 Trying to install 16 bit DAC. Should
improve regulation.
7.2 Position control on Hadron Collimator good to
100 microns. Working on cleaning up displays.
7.3 Electron collimator has problem with noise in
the encoder.
7.4 Electron dipole had problem yesterday with lead
voltage trip. Problem traced to failed
components in protection circuit. Being
repaired.
8 Detectors: (Bogdan Wojtsekhowski)
8.1 Electron Arm VDC hard stop is now in place.
8.2 All detectors are now in their final place.
Data base must still be updated.
8.3 Hadron Arm VDC is ready to have its hard stop
welded in place.
8.4 Shower counter studies show very little drift
in gains (+-3% to +-10%) between December and
now.
8.5 Re Gas Cerenkov: rechecking magnetic fields at
phototube bases. So far seeing no more than
0.1 Gauss with magnets powered for 4 GeV/c.
9 Hadron Arm Commissioning and Waterfall: (Meihua
“Meme” Liang)
9.1 Horizontal and vertical movement checked by the
Italians before leaving.
9.2 Starting to work on alignment software.
9.3 More survey training available next week. Chris
Curtis has agreed to leave a theodolite in the
Hall all the time.
9.4 Has made new counting rate estimates for 2.4
and 1.6 GeV. Will discuss at data analysis
meeting on Thursday (17 April)
10 Cryotargets: (Jian-Ping Chen)
10.1 Dimitri Margaziotis reports on latest He cell
tests.
10.1.1 Proudly displayed target cell and cell
block assembly
10.1.2 exceeded design goals. Went to 600 psi
but were unable to burst it.
10.1.3 Cell and block tests are complete
10.1.4 Will make new cell and block
incorporating changes.
10.1.5 Have completed first phase of the design
of the gas handling system. Expect to
finalize in the next month or so.
10.2 Gas panel and tank installed in the Hall. Leak
checking and repair underway.
10.3 Looking into safety issues regarding gas panel
wiring. Expect to start work on the actual
wiring during the next major shutdown.
10.4 Students working on valves and frequency
controller box.
10.5 Lars Ewell is preparing a 10 minute talk for
presentation at the APS meeting. Anyone
interested can attend a dry run at 1600 today
(15 April) in Trailer City 84.
11 Re shift scheduling: Riad says he has enough
volunteers for this weekend. Requests that in
general people volunteer more often for night
shifts.
12 DAQ: (Bob Michaels)
12.1 Working on arrangements for parity to run
parasitically
12.2 Fast Raster can run up to 80 Amps. Should be
good enough, depends on the details of the
optics.
-JJL