Beam Commissioning meeting Tuesday 16th September

Presentations

Notes

• Vacuum - Valves close at 4x10^-7. To open need cryo temperature and 3 gauges, to close just need 3 gauges (ion pumps count as gauges in this regard).
• Vacuum - 10^-8 sees alarm sent to vacuum group, higher before it's pushed to the operators
• Stable beam flag - agreed to change implementation (as above) to allow it to be set at 450 GeV etc. [To be revisited in shutdown]
• Security of mode changes - given that these are now Safe Machine Parameters. Should implement rigourously as state machine.
• BLM channels picking up a lot of noise - corrective measures being deployed. Crates, acquistion and logging look a lot more stable. MCS checks have advanced, High voltage modulation tests to be performed.
• TI8 dispersion: painstaking checks, re-matching etc. done and underway. Entry conditions at LHC very sensitive - no silver bullet.

Beam so far:

• B2: orbit corrected to 1 mm RMS with 2.5 mm peak. Bare orbit correction performed.
• 250 corrector polarities checked so far - all right.
• Integer tunes OK (64/59)
• Uncorrected tunes 11th September 0.368/0.208  (cf nominal 0.28/0.31) i.e off by 0.09/-0.1
• Uncorrected coupling around 0.06 to 0.07
• Energy - see Luca's presentation above

ML September 08