Search found 7 matches
- Tue Dec 08, 2009 8:32 am
- Forum: The Accelerator
- Topic: Beams have bunches in wrong bucket; abort gap??
- Replies: 10
- Views: 16510
Re: Beams have bunches in wrong bucket; abort gap??
They now have refilled for one bunch into bucket #1. It does seem to have been a Super Proton Synchrotron vs LHC timing issue, per operator's log: B1: CIRCULATE AND DUMP to check that now we inject bunch 1 in bucket 1. Philippe confirms that this is the case but that there is a phase problem between...
- Tue Dec 08, 2009 6:36 am
- Forum: The Accelerator
- Topic: Beams have bunches in wrong bucket; abort gap??
- Replies: 10
- Views: 16510
Re: Beams have bunches in wrong bucket; abort gap??
Oops, I see I responded hastily to jmayes; at the four crossover points, both beams do share the same pipe, and protons collide head-on (low angle). As somebody stated in the crossover thread, collisions are turned on by shifting beam path rather than bunch timing. Daavery, thanks for the info! They...
- Tue Dec 08, 2009 5:54 am
- Forum: The Accelerator
- Topic: Beams have bunches in wrong bucket; abort gap??
- Replies: 10
- Views: 16510
Re: Beams have bunches in wrong bucket; abort gap??
The two beams run through separate pipes except at the crossover points, and I've seen diagrams that show the beams being focused and entering the crossovers at a significant angle -- so the site of collisions shouldn't be very timing-dependent. It's also my understanding that the RF system keeps bu...
- Tue Dec 08, 2009 4:46 am
- Forum: The Accelerator
- Topic: From the operator's log...
- Replies: 1
- Views: 4720
7 Dec Night: beam running, wrong buckets
From the 7-Dec Night shift: 23:22 Precycle ongoing in all sectors. All vac valve open 23:53 All circuits finished precycle 00:54 1x1 bunch injected. Lifetimes ~ 25 hr, Problems with BPMs: not all reading out ... restarting BPM processes on Fesa servers for the BPMs 01:09 We proceed with the injecti...
- Tue Dec 08, 2009 4:38 am
- Forum: The Accelerator
- Topic: From the operator's log...
- Replies: 1
- Views: 4720
From the operator's log...
The LHC Operator's Logbook is a gold-mine of information, but a little awkward to keep tabs on. So I propose that we post entries of interest to this thread, where they'll be more widely available. Logbook entries are based on shift (starting date, day/evening/night) with timestamped entries, so an ...
- Tue Dec 08, 2009 4:31 am
- Forum: The Accelerator
- Topic: Beams have bunches in wrong bucket; abort gap??
- Replies: 10
- Views: 16510
Beams have bunches in wrong bucket; abort gap??
As of 8-Dec 0329 (CERN time), the operator reports that the bunches in both beams are about 128 buckets behind where they should be; cause unknown. They're expressing concern because this puts the bunches only 83 slots ahead of the " abort gap ". Does anybody here know what role the abort gap plays,...
- Mon Dec 07, 2009 8:15 am
- Forum: Portal link and forum suggestions
- Topic: Forum question: section/thread for LHC at-the-moment status?
- Replies: 11
- Views: 18283
Forum question: section/thread for LHC at-the-moment status?
Which forum board and thread is the appropriate place to chat about short-term LNC news -- for example, asking if anybody knows more about the current Sector 4 refrigerator shutdown? Each such event doesn't deserve its own thread, but I haven't spotted one yet with a suitable subject. Thanks much fo...