I noticed that PR2 verical OSEM, especially V1, is almost out of range (fig1).
Since all vertical sensor positions have an offset in the same direction (IM position is too high with respect to IRM), is it possible to move BF down and SF up to save the range of OSEM?
I adjusted the height of the SF and BF keystone so that the IM V1 OSEM could be in the linear range. Though the BF setpoint was changed by -1500, the IM V OSEMs were changed by only 176~275. The deviation of the BFD V (+910) was also inconsistent with the SF setpoint change (+1500).
| Before [um] | After [um] | |
| IM V1 | -461 | -186 |
| IM V2 | -271 | -95 |
| IM V3 | -254 | -24 |
| SF setpoint | -3000 | -1500 |
| BF setpoint | 862.8 | -637.2 |
| BFD V | 154 | 1064 |