Minutes of Hall A Group Meeting May 4, 2010
1)	Run Report: Aidan Kelleher
a)	For full details see 
http://www.jlab.org/~kelleher/RC/RC_04may10.pdf
b)	During last week did mostly 12C running
i)	There was a vacuum problem that was fixed on 
Thursday (4/29)
ii)	Used the time to correct many systematic
(1)	Target noise
(2)	False asymmetry due to the pockels cell
(3)	Time constant differences between BCM’s 
and detectors
(4)	Many systematic effects canceled by the 
Wien flip
c)	Production running on lead since Sunday (5/2) 
owl.
d)	Status:
i)	21 C as of this morning (out of 130 C)
ii)	Extensive Compton work performed
iii)	Pockels cell driver replaced
iv)	Target vacuum is holding
v)	Techs working on right Q1 (power supply control 
boards)
vi)	"High Radiation Watch" is required
e)	Please coordinate all work in the Hall with the 
Run Coordinator
2)	Installation: (Ed Folts)
a)	Supporting the present experiment
b)	Getting ready for the next experiment
3)	Al Gavalya
a)	Whit is working on the lead wall for SRC. The 
detector stack problem is solved.
b)	Joyce and Al working on the black box for DVCS
c)	Detector mount for DVCS is in the shop
d)	Meeting later this week with survey to discuss 
the DVCS needs
4)	Bert Manzlak
a)	Reminds all to report 1st aid incidents to health 
services. Use the occupational health services. 
It’s free and they’re good.
b)	Summer is coming. Make sure all summer workers 
have all the training they need.
5)	Javier Gomez adds:
a)	Also report 1st aid incidents to the Hall Leader
b)	Reminds that when you "escort" someone, you must 
stay with them.
6)	Sirish Nanda
a)	Compton:
i)	Cavity has been losing power steadily. Was down 
to 400 Watts
ii)	Suspect mirrors are losing their finesse.
iii)	Changed the mirrors during the open house
(1)	PPLN crystal broke
(2)	Laser realigned
(3)	Cracked polarizer replaced
(4)	Original fiber amplifier is back from 
the manufacturer and is back in.
iv)	This morning baking was completed
v)	Working to establish resonance in the cavity
vi)	Expect it will take at least several more 
hours
7)	Jixie Zhang
a)	Did a Møller measurement last week
b)	Still analyzing
c)	Expect to take another run tomorrow (5/5)
d)	New DAQ and old DAQ showing a systematic 2.5% 
difference in the measured asymmetry. Still 
trying to understand this.
8)	Doug Higinbotham
a)	HV crate from CLEO had communication problem, but 
we were able to get a crate for DVCS from M. 
Jones.
b)	There is a Java solution for the Right HRS crate 
if people don’t like using telnet.
c)	Attention is called to the Users Group Election 
ballot. 
http://www.jlab.org/user_resources/usergroup/ball
ot.html

-JJL