Presentation on theme: "R. Michaels PVDIS at Nov 2009 Beam Requirements for PVDIS Property ValueRun-Avg Hel. Correl. 1-Day Hel. Correl. Energy 6 and 4.8 GeVdE/E < 1 ppm < 5 ppm."— Presentation transcript:
R. Michaels PVDIS at Nov 2009 Beam Requirements for PVDIS Property ValueRun-Avg Hel. Correl. 1-Day Hel. Correl. Energy 6 and 4.8 GeVdE/E < 1 ppm < 5 ppm Current ~100 uA 1 ppm 5 ppm Position 0 (normal tolerance) 50 nm 250 nm Angles 0 (normal tolerance) 50 nrad 250 nrad Transv. Beam Polarization 0 Vert: < ~2 0 Horiz.: < ~12 0 same X or Y X’ or Y’ Explain another time
R. Michaels PVDIS at Nov 2009 Diffs = helicity-correlated diffs in microns. 0.005 um = 5 nm 1 slug = 1 period of half-wave plate state ~ 24 hours “Sign corrected” = put in a sign flip correlated to half-wave plate, to show the effect of HCBA on combined sample. HAPPEX-3 Fall 2009 ~ Energy ~ 150 nm
R. Michaels PVDIS at Nov 2009 “Parity Quality Beam” good enough for PVDIS Marginal for PREX ( especially BPM12x ~ Energy ) Interception at Injector ? Some reductions in diffs after work done at injector e.g. after Sept 15 and Oct 15 work Largest Component of diffs flips sign with half-wave plate Could be a Pockel Cell “steering effect” Could be electronics pickup from Pockel Cell Seems ruled out by PC-off runs. Big asymmetries, small derivatives wrt beam parameters Speculative hypothesis on next slide.
R. Michaels PVDIS at Nov 2009 Speculative Cause of BPM12x (Energy) diffs Electronics pickup from Pockel Cell ? Very small, but “amplified” somehow when slits closed Improved injector tune in last week seemed to fix it. Strategy Watch the slug plots during PVDIS If not good enough, may revisit pickup issue & injector transmission issue if PVDIS allows or requires. Can affect the beam, as during Happex-He. Turns into an Energy diff. (K. Kumar)
R. Michaels PVDIS at Nov 2009 PVDIS Run Plan Down time Oct 28 ~ Nov 4 ? Swap detectors, cabling work, target work Commissioning Nov 4 ~ 7 Establish good detectors, target boiling tests, Compton tests, Parity quality beam, BCM calibration, PVDIS DAQ. Production to Dec 23 Take data on LD2 Periodic Auxiliary Measurements Compton Issues Moller, Q 2, Backgrounds Transverse Polarization Test Run (2 shifts, Invasive !) Backgrounds Explain next week