Minutes of Hall A Group Meeting March 9, 2010
1)	General Announcements: (Kees de Jager)
a)	Yesterday (3/8) we had a full day visit from 3H 
experts from Idaho National Lab.
i)	Recall we have a conditionally approved 
experiment on the books that requires a 3H 
target.
ii)	To clear the conditional approval requires a 
safety review of the conceptual design of the 
target.
iii)	Visit was extremely productive
(1)	Visitors were easy to talk to and gave a 
lot of advice
(2)	Site safety committee members were very 
supportive.
(3)	Have a task list to complete before 
organizing the safety review. Target date is 
1st week of June.
2)	Installation: (Ed Folts)
a)	M�ller target is back on the beamline
i)	Have a cooldown plan
b)	Septum and target are back in place on the pivot
c)	Refitting transitions after welding
d)	Re the schedule, we are behind and not making up 
time. Expect to start late.
e)	Kees adds that he spoke to Chris Curtis this 
morning and urged him to keep a 2nd crew in the 
Hall through Thursday
3)	Engineering/Design: Paul Brindza
a)	Working on Compton laser enclosure and doors
b)	Documentation of the Compton beamline is done
c)	Improving connections for the Y-can for M�ller
d)	Bolt pattern mismatch between the beamline and 
scattering chamber being addressed
e)	Working on correctors for the septum for APEX
f)	New hires:
i)	Robin Wines is transferring from engineering to 
Hall A (good magnet person)
ii)	Whit Seay, mechanical engineer, starts on the 
16th
4)	Jack Segal
a)	Trying to button up left Q3
b)	Problem with left Q2, hope to address it 
tomorrow.
c)	Dipole is OK
d)	Right arm is OK, set to 0.5 GeV/c with no 
problem.
e)	Argon/CO2 system is working, been flushing for a 
few days
f)	Kees adds that we need to be notified every time 
they cooldown the Qweak target.
5)	Sirish Nanda
a)	Compton:
i)	Last week characterized polarization transfer 
for the entire beamline
(1)	Found bugs
(2)	Polarization was only 92% at the center 
of the cavity
(3)	Replaced 2 mirrors now have 99-100% 
polarization
ii)	Full calibration will wait till after the 
experiment
iii)	Mounted new mirrors:
(1)	Observed lots of noise compared to in 
the laser lab
(2)	Noise suddenly stopped. A turbo pump 
died. Concludes that if you�re seeing 250 kHz 
noise it may be a turbo pump
iv)	Beamline not at vacuum
v)	Mirrors look good
vi)	Next challenge is locking the cavity
6)	Sasha Glamazdin
a)	M�ller:
i)	Met last week with accelerator people re M�ller 
FSD and procedures. Have drafted procedures.
ii)	Getting mixed signals re getting pulsed beam 
in Hall A with CW in Hall B. Hari Areti has 
succeeded in explaining to MCC how to put 
pulsed beam in Hall A and CW in Hall B
7)	Doug Higinbotham
a)	Uploaded the gamma,p paper to the server today 
(see: http://arxiv.org/abs/1003.1944 ). Last 
chance to make suggestions, it will be submitted 
on Monday
8)	J-P Chen
a)	Have two students, one from W&M, and the other 
from USTC. They have passed their laser training 
and started working in the target lab.
b)	Visited Los Alamos last week and gave a seminar
c)	This week there�s a workshop at Duke on semi-
inclusive reactions at EIC
d)	One can still make submissions to the MENU10 
conference, but time is short
9)	Ole Hansen 
a)	Have 4 GEM�s on site, 2 from Italy, and 2 from 
U.Va.
b)	Testing the GEM�s with HV
c)	Software is ready for checkout
10)	Bogdan Wojtsekhowski
a)	HRS Standard detectors:
i)	VDC and S2m are working �perfectly�.
ii)	S2m has some noise that has been traced to 
the delay line. (A nuisance but not 
problematic)
iii)	Preparing to install BigBite cards on HRS 
left VDC (50%)
b)	SBS:
i)	Collaboration meeting scheduled for March 19
ii)	Will discuss progress and new proposals. In 
particular, John Annands proposal to measure 
Gen with an FPP.
c)	Workshop at JLab at the end of May on exclusive 
reactions. All encouraged to register and attend.
d)	APEX:
i)	Preparations on going
ii)	Working groups formed for software and 
hardware
iii)	Approval is pending
iv)	Fringe field of PREX magnet steering the beam 
is a problem. Studying means to compensate for 
and shield it. A 6 inch magnet is available. 
Need to finalize and get approval.
11)	Arun Saha
a)	Rick is checking out the Arc Energy system. 
i)	New NMR is ready to go
ii)	Still need to check with beam
b)	Making progress on archival paper. Hope to have a 
draft out in the next few weeks.
12)	John LeRose
a)	Working with Bogdan on APEX & SBS
b)	Ready to do final calculations for PREX optics. 
Still waiting for final detector position.
13)	Al Gavalya
a)	DVCS calorimeter stand:
i)	Nearing completion on drawings
ii)	Waiting for rails
iii)	Drawing package went out for cost estimate
iv)	Still need standard engineering study on the 
carriage
-JJL