2010 Briefings, Schedules and Problems

[Danny252]

Those of you here last year may remember my collection and interpretation of the daily meetings/schedules at CERN, so why not do so again this year?

I'm currently going on the 0830/1700 meeting presentations, linked to under "Progress" on the Portal.

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Tues 2 Mar:
03:00: Recovered from cryogenics
03:00 – [0830] : Problems in closing QPS quench loop of main quad in S78 –Tunnel intervention is required
10:00 ?? Recovered
10:00 –12:00 : Pre-cycle for sectors 67 -78 –81 and BIC, Dumped beam event problem investigation
12:00 –16:00 : re-establish beam in the LHC
16:00 -18:00 : RF work (bucket number for beam 2), cavity phasing
18:00 –evening: Systematic beam 2 and beam 1 measurements and corrections
Over night : Beta beat measurements and possible preliminary aperture measurements

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Fairly routine plan, but as of 1300 Page 1 is still showing problems with the QPS in 78, with beam estimated at 1700 (2 hours from posting). The logs are still showing the QPS being awkward in 78 at 1350

To add to this, it sounds like the Patrol system playing up - I believe a patrol has to be done before locking [sections of] the machine for beams to make sure no one's busy hammering still, and it seems the systems associated with it aren't counting people in and out properly.

All in all, another standard CERN day!

[Danny252]

1730 Briefing:

17:00 -? Recovered
17:00 –19:00 : Pre-cycle for sectors 45 -56-67 -78 –81 and BIC, Dumped beam event problem investigation
19:00 –21:00 : re-establish beam in the LHC
21:00 –evening: Systematic beam 2 and beam 1 measurements and corrections
Over night : Beta beat measurements
Introduce RBAC –Postponed to tomorrow morning

Beams aren't in yet at 2030. Looks like Hump hunting tonight.

Edit: Typical, 2 minutes later they're doing the Injection Handshake.

[Danny252]

0830 Info:

Wednesday Schedule:
Until 9:00 : beta beating
09:00 -10:00 : Orbit study with 2 beams
10:00 –12:00 : Dump and Pre cycle –BLM intervention IR6 –RBAC activation
12:00 -15:00 : Re-establish beams and checks of parameters
15:00 -21:00 : Systematic hump investigation
21:00 –02:00 : Injection studies
02:00 –03: 00 : ALICE : beam on the TED
03:00 –07:00 : Aperture checks -tbc

Thursday Schedule:
07:00 –15:00 : HWC tests
15:00 –23:00 : Hump investigation continued
Overnight : beta beating measurements and correction

The obvious major work is Hump hunting and other fine tuning of the beam. Not sure what ALICE: Beam on the TED means - the TED being in would imply no beam in the LHC, so ALICE may be turning on their magnet or similar.

HWC tests, I believe, are Hardware Commissioning.

[LarryS]

TED is "Beam Absorber for Injection (External)" and is part of the protection system. Its mirror-image counterpart is TDI which represents "Beam Absorber for Injection (Internal).

Not all of their acronyms have a direct 'translation.'

[serych]

0830 Info:

02:00 –03: 00 : ALICE : beam on the TED

The obvious major work is Hump hunting and other fine tuning of the beam. Not sure what ALICE: Beam on the TED means - the TED being in would imply no beam in the LHC, so ALICE may be turning on their magnet or similar.

I think, they are measuring ALICEs background, when the beam is on TED. I suppose, that protons coliding with TED are producing some particles and as TED is near ALICE I think it could be seen there.

Jakub

[Danny252]

I was wondering if it might be something like that.

1700 Meeting:
21:00 –02:00 : Injection studies
02:00 –03: 00 : ALICE : beam on the TDI –5e9
03:00 –07:00 : Systematic hump investigation

Thursday:
07:00 –15:00 : HWC tests
15:00 –23:00 : Hump investigation continued –cryogenics tests for hump
Overnight : beta beating measurements and correction

Still more hump hunting - they were really going at it earlier.

[chriwi]

what are theese HWC-tests and is it that what they actually doing when theywrite "beams dumped, switching of the magnets, no beam from 7:00 to 15:00"?

[Danny252]

1700 Meeting has a monster timetable!

Thursday
•20:00 : LHC ready to take beam ?
•20:00 –24:00: Hump and He flow
•Overnight: beta beating measurements and correction IR2, IR3, IR8

Friday 05/03/2010
•07:00 – 11:00 : Establishing reference orbit – “golden” + intck BPM Pt 6
•11:00 – 24:00 : Switching on spectrometers + compensators – Correct on closure – coupling - use knob checks. In parallel: orbit, tune feedback
•00:00 - 07:00 : Switching the separation bumps on

Saturday 06/03/2010
•07:00 – 10:00 : HWC
•10:00 – 12:00 : Cycling and re-establish injection
•12:00 – 14:00 : Reserve
•14:00 – 22:00 : Injection and beam dump studies
•22:00 - 07:00 : Beta beat measurements

Sunday 07/03/2010
•07:00 – 15:00 : Collimator setting-up – BLM
•15:00 - 23:00 : Aperture measurements
•23:00 - 07:00 : Reserve

Monday 08/03/2010
Trial ramp – 2 beams – strategy for beta beat corrections

More fine tuning over the weekend, it looks like. Of course, I doubt the timetable will look anything like this on Sunday!

[serych]

1700 Meeting has a monster timetable!

Friday 05/03/2010
•07:00 – 11:00 : Establishing reference orbit – “golden” + intck BPM Pt 6

What could mean "reference orbit - golden"? It seems to have something to do with Beam Position Monitor in Point 6 (there were some problems with it), but the message is too telegraphic for me to understand

Jakub

[Danny252]

Sat 1700:

Early morning on Sunday 7 March: LHC re-start with beam - Perform beam checks (basic parameters)
07:00 – 13:00 : Injection and beam dump studies
13:00 – 23:00 : Collimator setting-up – BLM
23:00 - 07:00 : Damper setting-up

Apparently Cryo is being silly and needs some work until tomorrow, but no cryo work is needed on Wednesday as had (apparently) been reported previously.

Not sure what the Dampers are - all I can think of is the Dampers on a steam engine, and I doubt the LHC has those!

[Angrond]

The 'damper', 'transverse feedback system' or sometimes referred to with the even more shorter cryptic acronym 'ADT' system monitors an stabilises the transverse beam oscillations if their amplitudes are growing.

The 'golden orbit' is a historically evolved term describing a good (best -> see also 'gold standard') reference of the mean transverse beam position (orbit) along the ring. This reference optimises the available space (aperture) for the beam and/or magnetic feed-down effects. Also, the measured orbit is usually always brought back to this reference using dipole corrector magnets (aka. CODs) by the operational crew or orbit feedback system.

[serych]

Angrond, thanks for the clarification.

[Danny252]

0900 Schedule:

Sunday:
08:00 –14:00 : Injection and beam dump setting-up
14:00 –24:00 : Collimator setting-up –BLM
24:00 -07:00 : Damper setting-up

Monday:
07:00 –15:00 : Aperture measurements
15:00 –21:00 : Protection device checks and setting-up
21:00 –23:00 : Ramp trial without beam –collimator & BETS checks
23:00 –01:00 : Pre-cycle
01:00 –07:00 : Tune and orbit feedback

Aperture Measurements - this obviously relates to a gap of some sort, but since Collimators are mentioned separately earlier, what is it referring to?

[Angrond]

Here, the 'Collimation setting-up' refers to the relative alignment in between the primary, secondary and tertiary collimator sets whereas 'Aperture measurements' refers to the verification of the global and local aperture bottlenecks that need to be protected e.g. the experimental insertions or injection/extraction regions.

Both aspects are intertwined and the LHC crew may alternate in between them.

[Danny252]

No schedules in the 0830 due to a problem with an Emergency Stop Switch last night (which led to cryo problems), and the 1700 hasn't appeared yet!