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EG1-DVCS Highlights and Status. Erin Seder University of Connecticut. 0. +. -. Experimental Goals. DVCS ep ep g A UL A LL. DVMP ep ep p 0 A UL A LL ep ep h A UL A LL. SIDIS ep e p X A UL A LL. Target Material. Solid NH3 granules D ynamic N uclear P olarization
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EG1-DVCSHighlights and Status Erin Seder University of Connecticut
0 + - Experimental Goals • DVCS • ep epg • AUL • ALL • DVMP • ep epp0 • AUL • ALL • ep eph • AUL • ALL • SIDIS • ep ep X • AUL • ALL
Target Material • Solid NH3 granules • Dynamic Nuclear Polarization high polarizability (~82%) • Monitored using Nuclear Magnetic Resonance • Resistant to radiation damage • Repaired by a process of annealing • 2 Samples • Irradiated in 2005 – top target • Irradiated in 2007 – bottom target Carbon Empty
Polarized Target Cryostat Banjo chamber containing the target in a bath of LHe Refrigerator cools the banjo from 4 to 1K using evaporative cooling Magnet 5T superconducting magnet P1/2 = tanh(mB /kT)
NMR Monitoring Negative Positive changing polarizations m wave frequency 139.61GHz 121.33A 139.90GHz 121.4A Magnet current Top target Bottom target anneal neg neg pos pos neg pos
Target/BeamPositioning & Crosshair for Alignment RasterSize Target Cup Wall Raster x, y = 750 mV (~6.7 mm)
Accumulated Charge • Beam energy = 5911GeV • Beam current = 7 nA
Kinematic Plots for ep->eX • Electron PID: • dc(), cc(), sc(), ec() > 0, • dc_stat(), ec_stat(), sc_stat() > 0 • EC_tot/p > 0.2, • EC_inner > 0.06, • nphe > 25, • minimum momentum cut > 1.0 GeV, • -61 < vertex(e) < -56
Q2> 1 GeV and W>2 GeV events Beta vs. momentum and mass distribution for positive and negative tracks