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User name pzhu
Log entry time 15:42:52 on April 5,2012
Entry number 370429
This entry is a followup to: 370419
keyword=spot_3 and spot_Rthis is spot_3 and spot_R for the beam position check.
First picture is taken in the C12_hole target to check the center beam position by using spot_3, you can see the similar spot_R in the second picture(right side of the first picture).
Unfortrantly, While jixie tried to move target to C12_40 target, beam position moved by itself. you can see the spot_3 and spot_R in the third picture and fourth picture, it hits the target cell.
the beam position in the 1st and 2nd picture is:
IPM1H05A.XPOS : 1.72112
IPM1H05A.YPOS : -1.57031
IPM1H05B.XPOS : -1.37446
IPM1H05B.YPOS : -3.19732
the beam position for 3rd and 4th is:
IPM1H05A.XPOS : 0.901938
IPM1H05A.YPOS : -1.11447
IPM1H05B.XPOS : -1.6126
IPM1H05B.YPOS : -3.16078
The beam position locker works bad, MCC said they can only lock 2 signal, i.e., can only lock 1H05B x and y.
Also, when slow raster on, epics bpm spot size is huge(about 0.5mm), maybe it is better to reduce filter frequency to low than slow raster frequency so that we can get more accurate beam position in the epics even if the slow raster on. also it is helpful for beam position locker.
FIGURE 1
FIGURE 2
