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BPM Status

Pengjia Zhu

2013.9.11

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3.13 3.14 3.173.9 3.273.6straightthrough

2.5T90 deg

2.5T90 deg

5T6 deg

septumfired

3.292.5T90 deg

2.257GeV3.17 run 3273 raster size calibration

BPM A BPM B

BPM B constant destroyed

using 3.14 constant

BPM A constant works good

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Reason:div changed from 4 to 2 for both BPM A and BPMB after 3176 run-> gain changed (auto gain, gain diff between + and - did not change)(I was thought the div will not change the position)

BPM A seems was not affected BPM B tragedy

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3.13 3.14 3.173.9 3.273.6

auto gain

straightthrough

2.5T90 deg

2.5T90 deg

5T6 deg

septumfired

3.292.5T90 deg

3.14 straight through harp scan

3.16 2.5T harp scan

timeline

3.16 harp scan have 3 runs with div=2 for BPM B (with target field)

Luckily...

BPMA BPMBharp 05

can use BPM A and harp05 to calibrate BPM B

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Unfortrantly...

survey uncertainty -> 0.25 mmBPMA resolution limit ~ 0.15mmBPMA,BPMB,Harp are close (941,814,677mm)three harp scans' pos too close ~ 1-3mm

The calibration failed

pos got from BPMA and harp05

BPM B data

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New method to calibrate BPM-- brute force calibration

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first step

beam position at targetgot from carbon hole~ 0.4mm uncertainty at target

BPMA

Reliable BPM A position

center position at BPM B

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packaged used: pyQT, matplotlib

ideal shaperadius and center position from BPMA and carbon hole

calibrated BPM B shape

only raster x turn on

only raster y turn on

sliders,manualy change constant

check if rotation changed

visually see the changes

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raw shape -- with 3/14 calibration constant

ideal shape

BPM B shape

only raster x turn on

only raster y turn on

check if rotation changed

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optimized

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3185 x position at target by using new constant

matched with Chao's fit result

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Futher optimize:Use circle fit to get carbon hole center position instead of eyesParameter to judge if circlular?

Another job for beampackage:Optimized bpm calibration code, much faster