RHIC/AGS Polarimeter Study

May 1, 2009

H. Huang, A. Zelesnki, B. Morozov

RHIC/AGS Polarimeter Study • Fixed target polarization for two intensities (1.4

and 1.6*10^11) with 12 bunches in both rings with two polarimeters. AGS measurements were done with similar intensity.

• Polarization profile measurements were done with both rings and both planes with 56 bunches. AGS horizontal and vertical profiles were taken the same time.

• Sweep and fixed target measurements were done with 56 bunches for comparison.

• Note: Keith tuned emittance down for AGS before the study, we did not see much change on AGS IPM or CNI target scan, but the polarization profiles measured in AGS is flatter than before.

Yellow Vertical Polarization Profile

Yellow Horizontal Polarization Profile

Polarization Profiles of RHIC and AGS

ring Horizontal P0 sigma Vertical P0 sigma

AGS 60.453+-3.341 3.981+-1.909 60.979+-2.374 3.994+-1.491

Blue 55.915+-2.623 3.462+-1.258 60.089+-1.860 4.804+-2.294

Blue 64.523+-1.631 3.386+-0.427

Yellow 58.923+-1.162 3.732+-0.500 57.904+-1.661 3.482+-0.447

•The profiles are consistent between AGS and RHIC with the statistics.•The actually is P / I. These numbers from last year at 100GeV are averaged 2.5, this year is about 3(average of many fills). Given the large error bars, I can’t say there is profiles developed in RHIC ramp.

Polarization Ratio of RHIC vs. AGS

Intensity AGS blue1 blue2 yellow1 yellow2

1.4 59.97 2.61 56.3 3.1 59.3 2.7 50.5 3.6 60.6 2.3

1.6 55.36 2.64 56.15 2.19 52.59 1.79 52.7 2.3 51.26 1.83 b1/a b2/a y1/a y2/a

1.4 0.94 0.07 0.99 0.06 0.84 0.08 1.01 0.06

1.6 1.01 0.06 0.95 0.06 0.95 0.06 0.93 0.06

•The expected ratio: Blue/AGS 0.978; Yellow/AGS 0.991. (MacKay, Proc. EPAC06, p. 1795).•All measurements were fixed target measurements. Due to low statistics, it is hard to draw concrete conclusion.

Polarization Measurements: Sweep vs. Fixed Target

ring Sweep Fixed Target

Blue1 55.5+-1.8 51.8+-3.1

Blue2 60.0+-2.0 61.9+-2.7

Blue2 62.3+-2.3 64.4+-2.5

Yellow1 52.7+-2.1 58.2+-2.2

Yellow1 60.8+-2.4 60.3+-2.2

Yellow2 54.6+-2.3 56.5+-2.2

•Some measurements (blue1 and yellow1) are strange. But if you take all of them statistically, they show that the sweep measurements are ~1.2% out of 60%. •Combined with the data taken at 12 bunches and fixed target, we expect that the RHIC sweep measurement at injection lower than AGS by only 2-4% out of 60%. This is different from 109 bunch injection measurements.