Hall A Infrastructure and the Moller Parity Experiment

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

Hall A Major Equipment • Two SC high resolution (<10^-4) Spectrometers HRS left 4. 0 Ge. V/c HRS right 2. 8 Ge. V/c 12. 5 degrees minimum lab angle stand alone 6. 0 degrees with SC septa to 4. 0 Ge. V/c 5. 0 degrees with RT septa to ~ 2. 4 Ge. V/c • Big Bite spectrometer and detectors • Calorimeters and neutron detectors

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

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

Hall A Installed Utilities • Installed Hall A AC power 480 V 1800 A compare to Hall C 1800 A plus 2400 A @ 480 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 (~ 1 KW cryo-target coolant)

Hall A DC Power Supplies • 8 SC magnet power supplies 5 -10 Volts, 2000 -3500 Amps • Big Bite DC supply 125 Volts 750 Amps • New “spare” DC supply 10 V 3000 Amps • Lots of room for more (loaners) HES and HKS dipole DC supplies SOS DC supplies (3) Qweak DC supply

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

Torus Version of Moller Experiment From Dave Mack At least two more configurations are under consideration World’s highest power LH 2 target Scattered electrons drifted to Q 2 -defining collimator Moeller-focusing, resistive spectrometer Fits in endstation A or C 8

e 2 e. PV Target Requirements From Dave Mack • Target cooling power requirements are about 2. 4 times more aggressive than Qw(p) ( 5 kilo. Watt target) • Qw(p) already plans to increase helicity reversal to nearly 300 Hz in order to “freeze” density fluctuations. • Qw(p) target groups are now using finite element analysis codes to upgrade existing G 0 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. 9

Moller Parity Torus Geometry in Hall A Cryo-Target at -1. 5 meter from pivot

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!