Photon Polarization AnalysisBill Bugg

Data selection:1) PCALE Max cut2) Visual Inspection. For every cycle of every run we plot

and examine a series of histograms and scatter plots of signals from individual counters.PCALE,D,C,BAg1SicAg2SicAg1Ag2GCALCsI (channel 9)ToroidPossi TL,TR,BL,BR X,Y, etc.We look for changes in toroid current, or beam position, saturated channels, missed undulator pulses during the cycle and eliminate runs on this basis.

3) Adjacent runs with opposite field are treated in pairs and averaged to obtain the global asymmetry.4) To more closely monitor the results I divide the data into

segments of approximately 20-30 pairs(60 run cycles) which are examined separately and then combined.

5) For now I chose not to remove ‘flyers’(results outside 3 sigma) unless study of data for the cycles involved identifies a problemmissed earlier.

ANALYSISIn routine analysis background is subtracted and counter data normalized to AG1SiC signal. (Ag1 works about as well) Signal ratios and the difference/sum value evaluated for each pair. For each segment the average value and standard deviation is recorded and a plot of diff/sum vs run pair number made.This is done for the transmitted photon signal measured by Ag2SiC,Ag2 and GCAL For target in data we evaluate asymmetries for CsI channel 9 (crystal 5) and two signals Possisum and AG1which should show no asymmetry.

The weighted mean and error of the segment results are then calculated for the entire sample.

A few selection examples follow.

Run 2542 target inGood

Run 2590 cycle 1Target out (Bad)

Run 1571 saturation of Ag2Sic(bad)

For target out data analysis has been completed for the selected runs from the June and September runs(about 200 runs).In addition target in results are obtained for superrun data(lens=340, spectrometer=140,about 450 runs) taken with 0.25X0 target. (Runs 2542-2631), A small amount of June data is also included.

Measurement of the transmitted photon asymmetry is made by 3 separate counters, Ag2Sic, AG2, and GCAL. Ag1Sic counts all photons with approximately equal sensitivity, Ag2 threshold is about 4.5MeV and GCAL signal is proportional to transmitted energy.

For target in data we also report the CsI (channel 9) asymmetry and in addition test for asymmetry in the AG1 and PossiSum signal both of which should be small. The latter is a test for asymmetry due to possible effect of analyzing magnet fringe field on the positrons striking the reconversion target.

diff/sum ag2sic/ag1sic-- no background correction

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0 5 10 15 20 25 30 35 40 45Series1

Example data from June runs 1340-1515

diff/sum ag2/ag1sic

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0 5 10 15 20 25 30 35 40 45

diff/sum ag2/ag1sic

diff/sum gcal/ag1sic no background correction

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0 5 10 15 20 25 30 35 40 45 Series1

dif/sumcsi/ag1sic

-0.08

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0 5 10 15 20 25 30 35 40 45 dif/sumcsi/ag1sic

abs transmission no background correction average=1.95+-0.09%ag2sic/ag1sic

0.01750.018

0.01850.019

0.01950.02

0.02050.021

0 5 10 15 20 25 30 35 40 45

Series1

abs transmission background corrected average=2.00 +-0.09%ag2sic/ag1sic

0.018

0.0185

0.019

0.0195

0.02

0.0205

0.021

0.0215

0.022

0 5 10 15 20 25 30 35 40 45

Series1

dif/sum possi/ag1sic not background corrected

-0.015

-0.01

-0.005

0

0.005

0.01

0.015

0 5 10 15 20 25 30 35 40 45

dif/sum possi/ag1sic

This was the result that made us wonder if fringe field of Analyzing magnet was affecting CsI asymmetry. Possold had a definite asymmetry which was of opposite sign to CsI asymmetry.

diff/sum ag2sic/ag1sic no background correction

-0.15

-0.1

-0.05

0

0.05

0.1

0 10 20 30 40 50 60 70 diff/sum ag2sic/ag1sic

September data tuns 2542-2548

diff/sum ag2/ag1sic no background correction

-0.2

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0 10 20 30 40 50 60 70 diff/sum ag2/ag1sic nbc

diff/sum gcal/ag1sic no background correction

-0.15

-0.1

-0.05

0

0.05

0.1

0 10 20 30 40 50 60 70 diff/sum

dif/sumcsi/ag1sic no backgrouns correction

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0 10 20 30 40 50 60 70

dif/sumcsi/ag1sic

diff/sum possisum/ag1sic no background correction

-0.01-0.008-0.006-0.004-0.002

00.0020.0040.0060.008

0.01

0 10 20 30 40 50 60 70

diff/sum possisum/ag1sic

Possisum asymmetry is consistent with zero

abs trans ag2sic/ag1sic no background correction

0

0.001

0.002

0.003

0.004

0.005

0 10 20 30 40 50 60 70

abs trans ag2sic/ag1sic

runs asymmetry %target out average + stdev + error + average - stdev - error - events/run1151-1255 ag2sic 3.39 0.93 0.25(15) 3.41 0.62 0.15(18) 970

ag2 2.56 4.39 1.13 2.65 3.74 0.88gcal 6.91 3.52 0.91 6.4 2.28 0.54

2159-2228 ag2sic 4.49 2.17 0.62(13) 3.39 2.16 0.5(17) 950ag2 saturatedgcal 4.61 4.48 1.06 3.65 2.53 0.63(13)

2329-2429 ag2sic 3.59 1.7 0.33(26) 1500ag2 2.69 4.34 0.85gcal 3.1 1.97 0.38

2438-2529 ag2sic 3.16 2.69 0.53(26) 1500ag2 1.59 6.15 1.21gcal 2.82 2.71 0.54

2541-2628 ag2sic 3.45 2.02 0.42(23)ag2 3 3.26 0.68 1500gcal 3.25 1.78 0.37

2635-2797 ag2sic 3.98 2.08 0.34(37)ag2 3.25 3.58 0.58gcal 3.81 2.06 0.34

15002804-2828 ag2sic 2.87 2.83 0.96(9)NORMAL ag2 2.36 1.92 0.79

gcal 2.95 2.87 0.982855-2895FERRO ag2sic 2.56 3.38 0.87(15) 1500

ag2 0.86 3.55 0.92gcal 1.84 3.93 0.98

Target Out data by segment

runs asymmetry %target 0.5mm W average + stdev + error + average - stdev - error - events/run1340-1515 ag2ssic 3.94 0.57 0.13(19) 3.99 1.03 0.24(18) 2000

ag1ag2 4.57 1.94 0.45 4.5 2.94 0.45gcal 3.79 0.74 0.17 3.78 1.29 0.17possisumCsI 1.16 1.54 0.36 1.14 1.88 0.43

2034-2158 ag2ssic 4.31 1.74 0.36(24) 3.86 1.65 .33(25) 1000ag1 SATURATEDag2 SATURATEDgcal 5.14 3.23 0.66 5.15 3.18 0.64possisum -0.14 0.79 0.16 0.27 0.74 0.15CsI 1.35 2.71 0.55 1.56 3.24 0.65

2542-2548 ag2ssic 3.58 1.7 0.31(30) 3.88 2.37 0.43(30) 1500ag1 -0.04 0.2 0.04 0.018 0.2 29ag2 3.94 3.55 0.65 4.08 3.58 0.65gcal 3.63 1.57 0.29 3.83 2.05 0.37possisum -0.082 0.23 0.04 0.02 0.32 0.058CsI 1.12 1.84 0.34 1.13 1.94 0.36

2555-2562 ag2ssic 4.68 2.13 0.48(20) 4.69 3.05 0.76(16)ag1 0.018 0.21 0.048 0.12 0.32 0.08ag2 4.04 2.57 0.47 4.4 2.58 0.64gcal 4.14 1.72 0.39 4.3 1.92 0.48possisum -0.02 0.43 0.095 0.23 0.65 0.16CsI 0.77 2.51 0.57 0.82 2.43 0.61

target 0.5mm W average + stdev + error + average - stdev - error - events/run2564-2570 ag2ssic 3.27 2.21 0.40(30) 3.44 2.02 0.375(.29) 1500

ag1 0.012 0.21 0.039 0.036 0.22 0.04ag2 3.49 2.79 0.51 3.7 3.14 0.58gcal 3.39 1.34 0.24 3.55 1.43 0.27possisum -0.12 0.47 0.086 0.084 0.41 0.08CsI 0.958 2.09 0.38 0.915 2.01 0.37

2585-2592 ag2ssic 3.97 1.56 .29(30) 3.62 2.8 0.57(24) 1500ag1 -0.023 0.26 0.047 0.069 0.29 0.06ag2 3.02 2.46 0.45 3.07 2.63 0.54gcal 3.44 1.19 0.22 3.35 1.6 0.33possisum -0.113 0.45 0.08 0.021 0.54 0.11CsI 1.11 1.7 0.31 1.33 0.97 0.2

2594-2602 ag2ssic 4.11 1.7 0.31(30) 2.76 2.35 0.48(24) 1500ag1 -0.04 0.15 0.028 0.12 0.23 0.047ag2 3.2 2.82 0.52 3.12 3.07 0.63gcal 3.53 1.69 0.31 2.83 1.87 0.38possisum -0.0013 0.273 0.05 0.3 0.62 0.13CsI 1.19 1.64 0.3 1.16 1.65 0.34

2605-2625 ag2ssic 2.99 4.5 0.83(30) 3.8 2.8 .53(24) 1500ag1 0.033 0.3 0.05 0.068 0.25 0.047ag2 2.37 3.7 0.69 2.23 2.58 0.49gcal 2.93 3.25 0.6 3.2 1.49 0.28possisum -0.082 0.33 0.061 0.072 0.29 0.055CsI 1.56 2.81 0.52 1.6 11.64 2.2

target 0.5mm W average + stdev + error +(19) average - stdev - error -(19) events/run2627-2631 ag2ssic 1.42 6.71 1.5 2.06 4.78 1.1

ag1 -0.025 0.22 0.05 0.0001 0.32 0.072ag2 2.04 5.4 1.2 1.54 5.28 1.21

Target in data by segment

target 0.5mm W average + stdev + error +(19) average - stdev - error -(19) events/run2627-2631 ag2ssic 1.42 6.71 1.5 2.06 4.78 1.1

ag1 -0.025 0.22 0.05 0.0001 0.32 0.072ag2 2.04 5.4 1.2 1.54 5.28 1.21gcal 2.59 4.85 1.08 2.48 4.84 1.11possisum -0.098 0.39 0.088 0.13 0.9 0.21CsI 2.94 10.14 2.26 1.62 6.21 1.43

Asymmetry %Target outweighted mean %error

ag2sic 3.531473 0.051825ag2 2.683052 0.155043gcal 3.967002 0.059846

0.25X0 Target Inweighted mean % error

ag2sic 3.679762 0.071897ag2 3.499242 0.072967gcal 3.623144 0.046247CsI 1.187983 0.13398