BPM

1. pedestal current

using designed pedestal run 1184.

plot urb.[BPMA,BPMB].rawcur.[1,2,3,4]
fit with gausian and take the means

result:
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change the pedestal for BPMA to :
615   543   393   406   
change the pedestal for BPMB to :
524   490   493   545 
//////////////////////////////////
figure:
BPM_pedestals_run_1184.png
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2. transformation constant

using several bulleye scan run 4139-4149

plot T-> urb.[BPMA,BPMB].rotpos[1,2]
to get the calculated rot position 1&2 
(unit m.)

     E-> IPM1H04[A,B].[X,Y]POS
get the epic for beam position as the control calibration
(unit mm.)


the transformation is as follow:

[X,Y] = [ [M11, M12], [M21 , M22 ] ]*[rot1, rot2] + [offsetX, offsetY]

using the following equations:


x_i        =       M11 *rot1_i          +M12 *rot2_i        + offsetX

x_i*rot1_i =      M11 *rot1_i*rot1_i    +M12 *rot2_i*rot1_i + offsetX *rot1_i

x_i*rot2_i =     M11 *rot1_i*rot2_i     +M12 *rot2_i*rot2_i + offsetX *rot2_i

with SUM over all i

Then we get 3x3 matrix equation which we can solve for M11, M12, and offsetX

repeated with M21<->M11 and M22<->M12 and offsetX<->offsetY


The same method for BPMB.


result:
//////////////////////////////////////////////
Please change the BPMA constants to:
0.602485 -0.692236 0.63174 0.678693 -0.000112514 -0.000796697
Please change the BPMB constants to:
0.70586 -0.76147 0.537663 0.679827 0.00429048 -0.00462376
//////////////////////////////////////////////
figure:
bpm_rotpos_epic_%d.png  (4139-4149)
bpm_rotpos_epic_4139_49(3).png //combine data