EG1-DVCS Highlights and Status Erin Seder University of Connecticut
Jan 06, 2016
EG1-DVCSHighlights and Status
Erin Seder
University of Connecticut
Experimental Goals
• DVCS
– ep ep• AUL
• ALL
• DVMP
– ep ep
• AUL
• ALL
– ep ep• AUL
• ALL
• SIDIS– ep eX
• AUL
• ALL
+0-
Solid NH3 granulesDynamic Nuclear Polarization high polarizability (~82%)
Monitored using Nuclear Magnetic Resonance
Resistant to radiation damageRepaired by a process of annealing
2 SamplesIrradiated in 2005 – top targetIrradiated in 2007 – bottom target
CarbonEmpty
Target Material
Banjochamber containing the target in a bath of LHe
Refrigeratorcools the banjo from 4 to 1K using evaporative cooling
Magnet5T superconducting magnet
Polarized Target Cryostat
P1/2 = tanh(B /kT)
NMR Monitoring
139.61GHz121.33A
139.90GHz121.4A
wave frequency
changing polarizationsPositive Negative
Magnet current
Toptarget
anneal
Bottomtarget
pos posneg neg pos neg
Target/BeamPositioning
RasterSize
&
Target CupWall
Crosshairfor
Alignment
Raster x, y = 750 mV
(~6.7 mm)
Accumulated Charge
• Beam energy = 5911 GeV
•Beam current = 7 nA
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
Kinematic Plots for ep->eX
Beta vs. momentum and mass distribution for positive and negative tracks
Q2> 1 GeV and W>2 GeV events