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Archived Messages for HALLA_MIN_1997@cebaf.gov: Minutes
Minutes
John LeRose (lerose@CEBAF.GOV)
Thu, 23 Jan 1997 09:21:05 -0500
Minutes of Hall A Group Meeting 21 January 1997
1 Hall Installation and running schedule (revision
118) presented for discussion by Bill Schneider.
1.1 Some details:
1.1.1 Beam for ARC test 13 February
1.1.2 Spectrometer commissioning runs start
around 20 February
1.1.3 16O starts in June, after May shutdown
1.1.4 Depends on revised accelerator schedule
not yet available.
1.2 Discussion included:
1.2.1 Possibility of postponing coincidence
commissioning at 4 GeV
1.2.2 Need to get automated control of slit box
in place to speed up commissioning runs
(fewer magnet changes)
2 Hadron Dipole: no news, waiting for cryogenics.
3 Engineering: (Ed Folts)
3.1 Changed exit window on Hadron Arm. Now centered
on Q3
3.2 Finished leak checking exit beam pipe
3.3 Have started looking at power cable
installation for Møller and Compton
Polarimeters. There is some question about
whether or not cable trays will be needed. Ed
is discussing with safety people.
3.4 TACL to EPICS conversion is done in principle.
May still be some small problems.
3.5 Started layout and installation of ep chamber
4 Commissioning: (Eddy Offermann)
4.1 Working on ESPACE manual
4.2 Working on software changes for coincidence
operation.
5 Controls: (Javier Gomez)
5.1 James Proffitt:
5.1.1 Working on ramp generators for the Hadron
Dipole. They have been tested in software.
We’re waiting for the magnet to cool.
5.1.2 Reorganizing data bases to reflect TACL to
EPICS conversion.
5.2 Sequence drivers for slit box have been tested
5.3 Crash buttons for magnet power supplies should
be operational in about one week.
5.4 Al Gavalya starting working on table for
alignment system.
5.5 Working with Pascal Vernin on adding wire
scanner ADC readout in order to be able to
cross calibrate wire scanner to BPM’s.
6 Magnetic Field Measuring and Monitoring: (John
LeRose)
6.1 Further studies of simple circuit analogs of
shorted Hadron dipole suggests a simple scheme
to ramp up and get nearly balanced current in
the shorted and unshorted coil packs. Ramp up
at constant voltage followed by linear
reduction in voltage gives balanced current in
both coils after some adjustment of the rate of
reduction in the voltage.
7 Møller Polarimeter: (Sirish Nanda)
7.1 Work continues on Quadrupoles in the Test Lab
7.1.1 Have had to retro-fit water connections
7.1.2 Should be ready for installation by the
end of the week
7.2 U. Ky. has vacuum system assembled and tested.
Will review at JLAB in February.
7.3 Ron Gilman reports on scheme to record helicity
changes.
8 Detectors: (Bogdan Wojtsekhowski)
8.1 Monitoring cosmic rays. Everything looks
reasonable.
8.2 Pb. glass look stable (except for step that
Bogdan says he understands)
8.3 Work continues on FPP
8.4 MIT team has made good progress with chamber
#5. It is now operational.
8.5 Discussion of maximum expected time resolution
from Scintillators.
9 DAQ: (Bob Michaels)
9.1 DAQ will be down:
9.1.1 a couple of days next week
9.1.2 for installation of new electronics the
following week.
9.1.3 Bob will try to coordinate with people
running detector tests
9.2 Reports studies to find the origin of the
“jumping” VDC stop times have traced the
problem to the MLU. Don’t have a solution yet.
9.3 Have learned scheme for getting information
from accelerator (BPM’s etc.) and incorporating
it into the data stream. Will try to implement
before the next run. Envisions a snapshot of
system status at the beginning of the run.
10 Cryo-Target and Compton Polarimeter: (Jian-Ping
Chen)
10.1 Design work continues
10.2 Techs working on plating of cell blocks
10.3 Have observed radiation damage to transducers
will need to either shield them or get
different, more radiation hard, transducers.
10.4 Fraser Duncan will be leaving in March.
Reorganization effort is underway.
10.5 Compton Polarimeter Meetings held last week re:
10.5.1 installation of magnets and power
supplies
10.5.2 vacuum design and component selection
10.5.3 radiation issues and safety problems
10.5.4 scope of work for EPICS slow control
11 Beamline: (Arun Saha)
11.1 The ep scattering chamber should arrive today
(we got word it arrived at 14:58)
11.2 Meeting tomorrow (22 January) re 16O experiment
15:00 in A110
11.3 Finalizing final waterfall target design. The
original target doesn’t allow all kinematic
settings. Prompted some discussion of what the
optimum target would be. E. Offermann maintains
that two foils would be better than three.
Should have a clearer picture of the new design
tomorrow. Go to 16O meeting to find out more.
In any case new target will not be ready by the
end of February.
11.4 Scheme for measuring angle changes discussed
with survey and alignment group.
12 Hadron Arm Electronics: (Meihua “Meme” Liang)
12.1 Has modified ESPACE for new scaler scheme.
Instructions have been circulated via e-mail.
12.2 This does create a compatibility problem
between old and new data
-JJL