Minutes of Hall A Group Meeting April 20, 2010
1)	PREX Run Report: (Doug Higinbotham for Guy Ron)
a)	For full details see: 
i)	http://hallaweb.jlab.org/news/minutes/RC_Summa
ries/PREX_RC_Report4-20.pptx.pdf
b)	Experiment is in Production Mode (since Friday 
4/16)
c)	There’s an analysis meeting this afternoon at 
1500, counting house 2nd floor, where you can see 
what the data looks like.
d)	Sources of downtime:
i)	O-ring: 4/1-14
ii)	ADC cabling: 2 hours
iii)	Q1 power cycling: 1 hour
iv)	Detector moves: 2 hours
e)	Monitoring various temperatures in the target 
area.
i)	W collimator: ~500 C @ 54 micro Amps
ii)	Beamline: 105 C
iii)	Sieve box: 50 C
iv)	Setup looks stable now.
f)	Working on Møller problems
g)	Want to keep taking data.
h)	Plans:
i)	Contemplating going to higher current
ii)	Keep the present set of Thermocouples 
active. They’re a good indication of what’s 
happening with the beamline.
i)	Thanks to Ed, Jack, and Technical staff. They’ve 
done a wonderful job.
j)	Thanks also to Jay Benesch. The beam looks very 
good.
k)	Long discussion ensues re collimator, thermal 
stresses, Ion chambers, etc.
l)	Re metal o-rings, the company says it won’t work. 
They refuse to even sell us one.
m)	There are lots of neutrons in the Hall when we 
use the lead target.
2)	Engineering/Design: Paul Brindza
a)	Mostly working on DVCS setup
i)	Main frame arrived and is in the testlab
ii)	Re-designing neutron detector
b)	Waiting for information on g2P
c)	Robin is starting work on SBS TOSCA model. 
Presently having computer license problems.

-JJL