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Minutes of Hall A Group Meeting , 30 September 1997
1 General Announcements: (Kees de Jager)
1.1 We now have liquid Hydrogen and Deuterium in=20
the target cells. Congratulations to Jian-Ping=20
and his team.
1.2 Javier and Bob need to sign their timesheets!
1.3 Raises will be implemented as of 1 October.
2 Installation: (Ed Folts)
2.1 Made good progress during the shutdown.
2.2 Nothing to stop close-up tonight.
2.3 Work still to be done on pointing system.=20
Javier to get together with Ed.
2.3.1 Will need surveys to calibrate pointing=20
for the Deuterium experiment. Scheduling=20
is problematic.
2.4 Presently Hadron arm is at 71 degrees and=20
Electron arm is at 145 degrees.
2.5 HPS (Horizontal Positioning System) not tested=20
yet. Operational tests this afternoon.
2.6 M=F8ller target cooling valve sometimes sticks in=20
the open position and you can=92t tell remotely=20
that it has. Not a problem for this run.
2.7 Ed will be going through the checklist from=20
1500 till 1800 today. Everyone should leave him=20
alone.
2.8 Exit beam pipe was found to be 3/4=94 high at the=20
dump end and 1=94 low at the target end. Target=20
end was corrected.
2.9 Visual inspection of the diffuser and dump=20
showed signs of two locations for beam passage:=20
Through the center of the window and through=20
the flange. Corresponding spots were seen on=20
the beam dump. Conclusion is that at some point=20
we were sending beam through the flange. 3=94=20
high and slightly to the side (one o=92clock)
2.10 Re removal of mildly contaminated material from=20
the Hall Kees announces that if we have no=20
plans for any future use for it we can turn it=20
over to Radcon, otherwise we are responsible=20
for its safe storage. Paul Brindza will look=20
into a shared storage facility with Hall C for=20
the short term.
2.11 Hadron Dipole power supply: expect to finish=20
repairs this afternoon, but will need 2-3 days=20
to test. We will do beam instrumentation tests=20
tomorrow and adjust plans after that.
3 Larry Cardman gives list of outstanding documents=20
needed for the Deuterium experiment to Javier.
4 Design: (Paul Brindza)
4.1 Work in progress on:
4.1.1 3He high pressure cell
4.1.2 Polarized 3He target (Tentative plans for=20
meeting 15 November and readiness review=20
12 December)
4.2 Still no news on septum magnets.
5 James Proffitt reports that Hadron Dipole power=20
supply UPS order has been put on hold by procurement=20
even though we needed it last week. Larry explains=20
that it is probably being held hostage by end of=20
fiscal year considerations.
6 Cryotarget: (Jian-Ping Chen)
6.1 Shows diagnostic plots (pressure vs.=20
temperature) demonstrating liquid in the H2 and=20
D2 cells.
6.2 Thanks to all who worked so hard (Riad, Gary,=20
Kathy, Lars, Mike Seeley=92s group, etc.)
6.3 Still have some minor fine tuning to do to make=20
remote operations more reliable. Should be=20
finished by 2200 this evening.
6.4 Kees points out that in November we will have=20
simultaneous operation of two cryotargets in=20
the end stations. This will require cooperation=20
between Halls A and C.
7 DAQ: (Bob Michaels)
7.1 Data Acquisition System is ready. CODA 2.0 is=20
working.
7.2 Raster is ready.
7.3 Pursuing putting a mesh box around the raster.
7.4 Trigger work completed last week.
7.4.1 Two new triggers (2 & 4) for measuring=20
detector efficiency. Details are posted on=20
the web.
7.4.2 Studied missing gate sources. 2 found.
7.4.2.1 Timing adjustments (repaired)
7.4.2.2 Electronic deadtime. Rate=20
dependent, 2.5% at 1 MHz. Will need=20
to repair before VCS runs.
7.5 ESPACE: have received 4 complaints. One problem=20
solved.
7.5.1 Kees suggests having a meeting to=20
organize better portability of ESPACE.=20
Suggested attendees include Bob, Paul=20
Rutt, Werner Boeglin, Michael Kuss, and=20
Ole Hansen.
7.6 Dave Prout reports on new things in the data=20
stream.
7.6.1 Amplitude from Raster coils is read event=20
by event in the data stream.
7.6.1.1 Discussion of plans to determine=20
phase shifts between readout and data=20
taking.
8 Detectors: (Bogdan Wojtsekhowski)
8.1 All detectors basically ready to go.
8.2 S1S2 need high voltage adjustment
8.3 Running tests with cosmic rays
8.4 Plan to build small chamber to control gas=20
quality in the gas shed.
9 Michael Kuss reports:
9.1 Gas Cerenkov PMT tests completed. Best tubes=20
installed.
9.2 Working on system to test quality of gas=20
samples. Will be ready to take gas samples=20
tomorrow (1 October)
10 Meme Liang reports on analysis of data from 89-003
10.1 First results, still have lots of corrections=20
to make.
10.2 Assorted plots shown:
10.2.1 Missing momentum vs. missing energy=20
(Emiss) .
10.2.2 Triple differential cross section vs.=20
Emiss
10.2.3 Response separation plot
10.3 Background subtraction discussed.
11 Beamline: (Arun Saha)
11.1 Working with Accelerator on procedure for=20
tuning the beam in the Hall
11.2 Need to get background measurements in Hall and=20
detector hut with various things in beam.=20
(targets, wire scanners, etc.)
11.3 M=F8ller review was held last week.
11.3.1 Have schedule of activities from now=20
until the parity experiment.
11.3.2 Need to suppress background at detectors.=20
Two things planned:
11.3.2.1 Collimator at entrance to=20
shielding insertion of dipole.
11.3.2.2 Lead shielding around exit beam=20
pipe from the dipole.
11.4 Reports that the 2 BPM=92s just upstream of the=20
target are not where they=92re supposed to be (5=20
and 20 cm off along the Beamline direction)=20
Will have to be moved to install superharp.
11.5 Position of BPM=92s have an observed x=20
(horizontal) deviation over time of 0.5 mm. At=20
first attributed to vacuum on and off but after=20
discussion spectrometer position is also a=20
possibility.
11.6 Checklist of information for Accelerator from=20
us is discussed.
12 Magnets and Optics: (John LeRose)
12.1 Shows results of further studies of optics and=20
possible explanations of changes in transfer=20
matrix of the electron arm in going from=20
400 MeV/c to 2 GeV/c. Possibility that observed=20
low field behavior attributable to mechanical=20
settling of the poles against their support=20
structure (first suggested by Al Gavalya) looks=20
plausible.
13 Controls: (Javier Gomez)
13.1 Cameras for angular readouts installed.
13.2 Received leveling system from France. Have=20
looked through parts at this point.
13.3 Having problems with new software from=20
Accelerator crashing IOC=92s on Hadron and=20
Electron arms.
13.4 Working on calibration of the pointing system.
-JJL
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