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User name Jin
Log entry time 20:32:31 on January20,2009
Entry number 257042
This entry is a followup to: 257005
keyword=Beam Position tuningThere was a series of BPM tuning from run 5384 to run 5388. The goal is to prevent beam from hitting cell wall as reported in Halog 257005.
However, when I only increased spot size to 6x6.6mm without touching BPM (run 5384), the hitting patten in Halog 257005 was not reproduced (figure 1 below). Then couple runs (5385-5387) moving spot around to figure out the direction and there were no obvious hitting too. Therefore, finnaly the beam is moved 0.5mm in the opposite direction (+X) of hit. And run 5388 checked this position is clear (figure 2)
run 5391 is the first production run after this tuning. Current BPM are:
BPMA = (-1.1 2.2); BPMB = (-0.4 2.2)
Just for record, Old BPM are BPMA = (-1.5 2.2); BPMB = (-1.0 2.2)
FIGURE 1
FIGURE 2
