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