Moller Polarimeter

General Information

This article will cover all things Hall-C Moller. currently, this includes all of the Qweak information. Information for past experiments can be found in the experiments section. This page is currently under construction, so please come back soon for more.

Documentation

The following is a plot showing good tune of the apparatus. It was taken Nov. 14, 2010 from run 475, with conditions: hallc:p is 1160.09 MeV, with a 1um target.

Also, a screen shot of the moller medm screen. Note the Q1 and Q2 currents, and the location of the collimators. This data may change, but should be accurate for the near term.

Moller Commissioning - Nov. 14, 2010

Initial Moller commissioning was on on November 14th, 2010. Polarizations up to 89% occurred. It consisted mainly from runs 476-490. Several targets, currents, and pre-scales were used. Collimator 5 was also removed for several runs to determine if scraping occurred. The following is a run summary:

Run    target  current(uA)  Camac prescale  Polarization (%)  Comments
477     1um      0.2          100            89.99+/-0.88  
478     1um      0.2          100            88.17+/-0.89  
479     1um      1.0          100            NA               junk
480     1um      1.0          1000           87.20+/-0.69  
481     1um      1.0          1000           88.91+/-0.71  
482     4um      0.2          1000           89.05+/-0.77     collimator 5 out
483     4um      0.2          1000           89.61+/-0.80     collimator 5 out
484     no tgt   1.0          1000           NA               collimator 5 out
485     no tgt   1.0          1000           NA               collimator 5 in
486     1um      0.6          1000           88.68+/-0.80     collimator 5 in
487     1um      0.6          1000           87.95+/-0.82     solenoid at 3.5 T, collimator 5 in
488     1um      0.6          1000           89.12+/-0.90     solenoid at 3.5 T, collimator 5 in
489     1um      0.6          1000           89.69+/-0.80     solenoid at 3.5 T, collimator 5 in, fast raster 2x
490     1um      0.6          1000           89.39+/-0.81     solenoid at 3.5 T, collimator 5 in, fast raster 2x2
491     1um      0.2          1              NA               solenoid at 3.5 T, collimator 5 in, fast raster 2x2

Moller spin dance

The initial Qweak Moller spin dance occurred November 23, 2010. Originally scheduled to coincide with Hall A, beam tune issues (on their end only) prevented a joint study.

Test setup: IHWP=OUT, QE=0.35%, Hallc:p 1159.66 MeV +/- 0.03. Solenoid at 3.5T, with 1 um foil. The current was adjusted using the laser attenuator, slit was wide open. Quoted polarizations are from the Dave G. scaler-bank-3-only analysis.

Run  Wein     Polarization       Comments
508  -0.1     40.04 +/- 1.23     200 nA
509  -0.1     40.05 +/- 1.88     1.05 uA
510  -0.1     40.40 +/- 1.03     1 uA
511  -0.1     40.13 +/- 0.68     0.9 uA
512  -0.1     40.19 +/- 0.70     0.9 uA
513  -0.1     40.13 +/- 0.70     0.9 uA
514  -0.1     40.14 +/- 0.65     0.57 uA
515  -0.1     N/A (junk)         Hall C laser off - no Hall A bleedthrough

517  +29.0    -2.75 +/- 0.65     0.9 uA
518  +29.0    N/A                Hall C laser off
519  +29.0    -3.70 +/- 0.69     0.9 uA
520  +29.0    -3.48 +/- 0.68     0.9 uA

521  -31.0    75.85 +/- 0.88     0.9 uA
522  -31.0    76.81 +/- 0.69     0.9 uA
523  -31.0    75.61 +/- 0.69     0.9 uA
524  -31.0    75.50 +/- 1.25     0.9 uA
525  -31.0    74.54 +/- 0.96     0.9 uA
526  -31.0    75.37 +/- 0.67     0.9 uA

527  -75.0    87.89 +/- 0.70     0.9 uA
528  -75.0    87.63 +/- 0.69     0.9 uA
529  -75.0    86.69 +/- 0.69     0.9 uA
530  -75.0    86.83 +/- 0.79     0.9 uA

531  -63.20   88.64 +/- 0.74     0.9 uA
532  -63.20   89.65 +/- 1.12     0.9 uA
533  -63.20   90.32 +/- 0.69     0.9 uA
534  -63.20   89.51 +/- 0.68     0.9 uA
535  -63.20   89.73 +/- 1.90     0.9 uA
536  -63.20   90.04 +/- 0.91     0.9 uA

The ideal horizontal wein angle was calculated to be -63.2 degrees. The measured polarization value at this wein was 89.62 +/- 0.35 (stat)%. Below the fit of polarization vs. Wein angle.

The original hclog result entries are #208285 and #208394.

Moller test summaries

Jan. 21, 2011

This was our first straight Moller measurement after the holiday down. Only a series of simple measurements were taken at varying currents were taken, no systematic studies. It was also hoped we could use this data to (eventually) calibrate BCM 17. Notice also the backgrounds remain consistent and reproducible from the December measurements.

Conditions: INHWP: In, QE=0.32%, HALLC:p=1159.82 MeV. Collimator 5 was out.

Run     Polarization      Note
686     -90.46 +/- 0.52   1 uA
687     -91.36 +/- 0.69   1.5 uA
688     -90.60 +/- 0.67   2.0 uA
689     -91.64 +/- 0.99   1.5 uA
690     -88.56 +/- 1.36   0.5 uA - bad beam position
691     -91.28 +/- 1.43   0.5 uA

Excluding run 690, the average polarization is -90.86+/-0.32%.

Experiments

• Sane Experiment
  • Sane Moller How-to

• Qweak
  • Qweak Moller How-to (coming soon!)