Mott Run 2 Journal

Prep and HCO w/o beam

1. (John) 31 MHz laser -
2. (Riad) Test laser RF trigger at DAQ
3. (Joe) Make a photocathode – SL5247-4 (52471-1 was used for Run I, but it's being removed from Gun2 next week)
4. (Marcy) Check Mott vacuum, configuration (hipot 3D01 again?)
5. (Joe) Cycle target ladder, test camera, test magnets, test 2D harp
6. (Riad/Daniel) Check HV, check DAQ, Analysis, Macros ready for 31 MHz
7. (Riad) Check DAQ data disk space

Pre-Run Beam Setup and Tests (2 shifts)

1. Recovery to FC2 @ 6.3 MeV by 10/15
2. Mott beam test - Test 31 MHz synchronization, set L/R/U/D delays, set PMT HV, check PMT response, dump dipole degaussed
3. Beam diagnostics - Test harp, BCM calibration, quick emittance method

Run II Proposed Plan (9 shifts 10/23 DAY - 10/26 OWL)

The goal is to collect final data set for the paper describing the performance and systematics regarding it's ability to measure the absolute polarization at 5.0 MeV.

2.0 shifts - Good knowledge of beam (energy, energy spread, emittance)

1. Set KE=5.0 MeV
2. Measure emittance at MQJ0L02
3. Measure energy spread at IHA2D00
4. Verify BCM calibration good
5. Calibrate PITA IHWP=in/out
6. Setup beam to Mott, check PMT HV, TOF spectra, set thresholds HI, check instrumental asymmetry
7. Setup spin direction, use Mott for final adjustment

3.5 shifts Target thickness extrapolation at KE=5.0 MeV

1. Use the 10 foils with 25mm aperture spanning 8 nominal thicknesses (0.05, 0.05, 0.225, 0.35, 0.35, 0.50, 0.625, 0.750, 0.87, 1.0)
2. Interleave 1um gold foils to demonstrate stabiilty

2.0 shifts Sensitivity of analyzing power vs. energy about 5.0 MeV

1. Imagine 0.5 shift/energy => 4 energies (4.0, 4.5, 5.5, 6.0)
2. In 1 hour: set nominal energy, measure precisely, forego emittance measurement but set spot size at target
3. In 3 hour: asymmetry measurements at 1.0, 0.75, 0.50, 0.225 um

1.0 shifts Repeat spot size and possibly energy spread systematic at KE=5.0 MeV

1. Use emittance measurement to calculate RMS beam size on foil (minimum, 1.0, 1.5, 2.0 mm)
2. Varying energy spread a bit more tricky since energy and to some extent emittance depends on phase in second cavity : maybe a measurement for another time?

0.5 shifts Asymmetry vs. beam intensity

1. Test beam and Mott spectra (TOF + discriminators) up to 100 uA to dump in through hole
2. Measure asymmetry 0.35 um foils (1, 5, 10, 25, 50, 75, 100 uA).