Shift 20101118

09:00 AA, LC, LD, LN

Plan

• Same as before - load 10nov17_0005.dat set file (MW's optics tweaked by AA and LD), tune for low background and trajectory, do laser/ e beam timing, search for collisions.

Start

Damping ring changed from 10 bunches, 0.78 Hz to 1 bunch, 1.56Hz. Lasers on. Seed cleaned (power up from 280 to 320mW) and tuned to lock.

Okugi-san tuning extraction. Loss in extraction line high and it appears that one of the OTR screens was in the beam. After ~ 2hours tuning access taken to swap polarity of QM11FF and QM16FF, as required by MW's optics design (only QM16FF done on 16th Nov).

11.20am Magnets changed - load up 10nov17_0005.dat.

12.10pm Beam very unstable and hard to tune. Near resonance in the DR - possibly only good solution is completer retune of DR. AA, GW, MW tuning DR and extraction line.

2.15pm OTR0 screen still in beam for some reason. GW removed it manually, orbit changed and background dropped. GW, LD tuning extraction line. LD removed attenuation from signal (1V, now at 14dB, ~ 6000 counts). LC retimed PCs for regen - moves to longer build up times and slightly lower energies as the system warms up. Output ~ 14.5mJ.

2.15pm Linac laser up to 40% to give enough charge in extraction line. GW saved 10nov18_1425.dat, fallback position file. Background very sensitive to excursions at QF11 and QD12. GW tuning these down then correcting down the rest of the line.

Wirescans / Background