1. Hall A Infrastructure and the Moller Parity Experiment “AMPEX”
Paul Brindza
August 14, 2008

2. Hall A Major Equipment
Two SC high resolution (<10^-4) Spectrometers
HRS left GeV/c
HRS right 2.8 GeV/c
12.5 degrees minimum lab angle stand alone
6.0 degrees with SC septa to GeV/c
5.0 degrees with RT septa to ~ 2.4 GeV/c
Big Bite spectrometer and detectors
Calorimeters and neutron detectors

3. Hall A Target Systems Cryo-target (3 cell/ ~800 watts) (H, D, He)
Polarized HE3 target system
Waterfall Target
UVA polarized target near future

4. Hall A Beam Line Instrumentation
Compton Polarimeter upgrade to 11 GeV/c
capable of CW non invasive measurement
Moller Polarimeter upgrade to SC magnet
Arc Energy Measurement system upgrade to 11 GeV
Beam Girder just upstream of pivot has super harps , BPM’s & BCM’s.

5. Hall A Installed Utilities
Installed Hall A AC power 480 V 1800 A
compare to Hall C 1800 A plus V.
Spare penetrations available for more AC in “A”
Installed LCW- same capacity as “C” at the wall, internal piping is smaller, easy to fix.
Installed Cryo ~ 500 watts at 4.4 K for HRS’
LHe at 4.4 K near pivot (xtra SC magnet coolant)
GHe at 15 K at pivot (~ 1KW cryo-target coolant)

6. Hall A DC Power Supplies
8 SC magnet power supplies
5-10 Volts, Amps
Big Bite DC supply 125 Volts 750 Amps
New “spare” DC supply 10V 3000 Amps
Lots of room for more (loaners)
HES and HKS dipole DC supplies
SOS DC supplies (3)
Qweak DC supply

7. Cryogenic Capacity-ESR Upgrade
Present ESR is ~ 1400 watts stand alone at 4K and ~1000 watts at 15 K
Present program requires constant supplement from CHL of ~ 10 gm/sec
ESR upgrade is part of 6 GeV hardening
preparation work for the 12 GeV era
ESR upgrade to 4 Kilo watt capacity
ESR upgrade plan - operational ~ 2014

8. Torus Version of Moller Experiment From Dave Mack At least two more configurations are under consideration
World’s highest power LH2 target
Scattered electrons drifted to Q2-defining collimator
Moeller-focusing, resistive spectrometer
Fits in endstation A or C

9. e2ePV Target Requirements From Dave Mack
Target cooling power requirements are about 2.4 times more aggressive than Qw(p)
( 5 kiloWatt target)
Qw(p) already plans to increase helicity reversal to nearly 300Hz in order to “freeze” density fluctuations.
Qw(p) target groups are now using finite element analysis codes to upgrade existing G0 design.
Astonishingly, sufficient cooling power is available on site, though more refrigeration would allow more flexibility in scheduling.
Highest priority is to build and test the Qw(p) target.

10. Moller Parity Torus Geometry in Hall A Cryo-Target at -1
Moller Parity Torus Geometry in Hall A Cryo-Target at -1.5 meter from pivot

11. Conclusion-Moller Parity in Hall A
Torus Version of Moller Experiment fits in Hall A
Locate Cryo-target at -1.5 M from pivot
Overall experiment length limited to ~ 27 M.
Other Moller Experiment schemes are possible but may require displacement of some Hall A Infrastructure
5 KW Cryo-target power is available now but only with significant Lab wide scheduling concessions
without the planned ESR upgrade in 2014.
AC, LCW, DC capacity adequate now for a
SC magnet Moller Parity Experiment.
LCW, AC & DC capacity for a resistive magnet
Moller Parity Experiment may require an upgrade.
AMPEX is a catchy name!