Shift 20120524 LC LN AA

Shift plan

• Load LW optics.
• OTR data - polariser data, during polariser analysis do LW spatial alignment.
• Quick OTR quad scan to find minimum σy. Also get σx for this beam.
• Try various skew quads to see which one rotates the beam significantly on the OTR screen.
• Tune for beam steering and background on LW detector - ideally < 7000 counts.
• Timing.
• Collisions search. Preliminary vertical/horizontal scans to find maximum of signal.
• Take long background and peak logs.
• Laser energy/signal correlation.
• Dispersion measurement - find out how to display the calculated dispersion at our location - and correction.
• Skew scan if good magnet found previously.
• Detailed long vertical and horizontal scans for full data collection.
• Vertical slices at various points through horizontal aspect of smallest beam.
• Quad scans - QM14FF first, then maybe another quad?
• Matching OTR quad scans.

PreShift Log

• Updated pedestal for ADCs with detector switched on, but no voltage and in addition laser closed for laserpd.

• 1000 pulse log after ADC pedestal update and with detector and laser off. 20120523_1955_log.dat

Shift

02:00

Tuning for background - odd orbit, hard to get background under 10,000 with 10dB of attenuation.

03:25 OTR scans

Rotation angle 4.32 degrees. Polariser scan min at 19.38 degrees. Set to 19.38. Try more OTR quad scans but beam charge very low so beam barely visible.

05:30

Laser running very low energy, bad signal to noise. Phase scan 20120524_0546_lws.dat, centre 3.05V. Background ~ 10,000 counts with 3dB attenuation.

06:00

Warning septum leak, beam off to investigate.

06:15

Not water leak, sensor is broken, beam back on. Vertical scan 20120524_0615_lws.dat, cetnre 809. Horizontal scan 20120524_0620_lws.dat, centre at 490. Move to this position.

06:50

Signal very low. Try different telescope settings - 5mm (large beam axis diameter 14mm, small beam axis 10mm) and 16mm (large beam axis diameter 10.5mm, small beam axis diameter 7.5mm). All telescope measurements from 17_5_2012.

5mm scan 20120524_0648_lws.dat 16mm scan 20120524_0652_lws.dat

No signal, return to 12.7mm (original telescope setting).

08:00

Signal decreasing, laser energy on post IP meter right down to 30 - 45mJ. Check laser, regen ~ 9mJ but not significantly worse than start of shift. Take access to check experiment - input window badly damaged, output window slightly damaged, lens fine. Gate valves around LWIP closed.

09:00

Discussion with Terunuma-san about operating accelerator, replacing window or moving chamber. Decided to operate machine and monitor vacuum closely (no sign of leak yet, window 56mm diameter, 12.7mm thick).

09.20

Beam on.