Polarized 3He Target Lab Update

Presented by Xiaohui Zhan

MIT

Hall A Collaboration Meeting, Dec. 14, 2007

Outline:

• Oven/Support Structure• NMR & EPR• New Oven & Other Designs• Optics Design & Orders• Vertical Coils Test• BigBite Frindge Field Investigation• Software & Target Spin Sign Signal• Cell Production• To Do List

Students: Chiranjib Dutta (UKY), Joe Katich (W&M), Xiaohui Zhan (MIT)Postdoc: Yi Qiang (DUKE)

Oven/Support Structure• Support piece on the bottom was burned, install new support structure.• Working well: ~250oC.• Old cell “Carlos” was installed for test.

Oven

Cell

NMR & EPR Tests

• Good NMR signal

• EPR underway…

New Oven/Optics

• Ordered from “Technical Products, Inc.”.• New materical: CS85 Structural Insulation.• Weigh 29lbs with supports (current oven ~ 45lbs).• Oven and support design was done, installation in February.

• Optics design is done!• Most optics components ordered and in house.• 6 single FAP and 2 duo FAP in lab, one new duo and single were ordered.• Alignment for 2 lasers was done for the tests.

Vertical Coils

R = 94.62 cm

Z: BeamlineY: Vertically upX: Normal to YZ

Measured Volume

Vertical Coil

• With 16A current, the average field generated by vertical coils is ~31 Gaus in Y direction (vertical).• Most field gradients inside < 10mG/cm (absolute value).• Large gradients (~20mG/cm) only happen at the edge of the volume.

BigBite Fringe Field

Transversity

g2/d2 (e,e’d)

Angle of BigBite -7o 8o 2.8o

dBx/dx

(mG/cm) 11.1 3.6 6.5

dBz/dz

(mG/cm) -13.3 -5.8 -8.7

dBz/dx

(mG/cm) 11.7 16.3 15.1

• BigBite clamp reduces the gradients by half compared to previous measurements.• But also introduce the mirror coils.• Simulation was done (Yi Qiang).

Results of Simulation (Transversity)

Gradient (mG/cm) dBx/dy dBy/dz dBz/dx dBx/dx dBy/dy dBz/dz

By =

28 G

Target Chamber

0.0±1.7 10.3±1.0 11.9±0.7 11.2±1.3 2.2±0.2 -13.3±1.1

Pumping Chamber

0.7±0.6 7.9±0.8 13.5±0.4 9.7±0.6 0.8±1.0 -10.5±0.6

By =

-28 G

Target Chamber

-3.4±0.9 -18.9±0.8 11.9±0.7 11.2±1.3 2.2±0.2 -13.3±1.1

Pumping Chamber

-4.6±0.7 -17.6±0.8 12.1±0.3 11.4±0.5 2.8±1.1 -14.2±0.9

Bx =

28 G

Target Chamber

-1.7±0.4 -4.3±0.1 18.0±1.6 15.7±5.3 4.8±2.2 -20.5±3.3

Pumping Chamber

-2.4±1.1 -2.8±1.4 18.4±1.3 15.5±1.2 -0.8±2.1 -14.7±1.8

Bx =

-28 G

Target Chamber

-1.7±0.4 -4.3±0.1 5.9±2.7 6.7±2.8 -0.5±1.8 -6.2±1.2

Pumping Chamber

-1.5±1.2 -6.3±1.4 7.2±1.4 5.5±1.3 4.5±2.1 -10.0±1.6

Target Spin Sign Signal+DAQ

• Flip target spin every ~20min• Hardware signal: goes to CODA datastream• Software signal: LABVIEW to EPICS• RF frequency monitoring & quarter-wave plate rotation monitor

Cell Production

• 16 new cells were done! (8 from W&M and 8 from UVa)

• Most cell polarization > 40%, a few>50%, max~60% (W&M)

To Do List

1. New oven test with all new cells (NMR, EPR, Spin-Flip).2. Cell characterization.3. New pick-up coils inside the oven.4. Target spin sign signal/DAQ.5. Target IOC.6. Software collection & analysis.

Will be ready before installation in May 1st, 2008!

Thanks to: Jian-Ping, Todd, Walfgang, Al, Susan, Jaideep, Ameya, Aidan…