Search found 64 matches

by dukwon
Mon May 21, 2018 6:35 am
Forum: The Accelerator
Topic: Looking ahead to LS2 and Run 3
Replies: 2
Views: 73

Re: Looking ahead to LS2 and Run 3

The figure of 300/fb was over Runs 1 to 3 (before the HL-LHC).
by dukwon
Wed May 16, 2018 8:16 pm
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

Look at the last few posts. 16L2 "woke up" and it took reduced beam intensity to get back to reliable stable beams. It was all going so well, too
by dukwon
Wed May 16, 2018 5:34 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

It was seen during scrubbing that the intervention to remove frozen air did not eliminate the problem. The best tactic was found to be adding bumps and restricting the current through the appropriate magnet. The working theory is still that is frozen air or similar. If there is water ice in there it...
by dukwon
Tue May 15, 2018 6:52 pm
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

16L2 has returned with vengeance over the last 24 hours: 21:52 Programmed dump in stable beams to end fill 6681 22:01 to 00:09 SPS cavity trip 02:22 Back to stable beams 02:57 Dump (stable beams) 16L2 03:29 to 05:19 MKI2 fault 07:03 Dump (flat top) no reason given in logbook 10:46 Dump (ramp) 16L2 1...
by dukwon
Tue May 15, 2018 7:50 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

even if nothing else has been discovered since the Higgs Discovering fundamental particles shouldn't be a main criterion for success. The LHC experiments have done a lot of physics in a variety of areas. Last time I looked they have published about 2,200 papers between them. so perhaps the remainin...
by dukwon
Mon May 14, 2018 9:05 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

Indeed, machine availability was >95% over the weekend, with 70% in stable beams. They are starting to gradually increase the bunch intensity. Fills 6675 and 6677 peaked at over 20 Hz/nb. The turnaround from 6674 to 6675 was 1:59:47; a new record! At the average rate over the last 2 weeks, we might ...
by dukwon
Wed May 09, 2018 3:05 pm
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

The water leak at point 8 last week was a bit more spectacular than I thought:
Fuite_SF8.png
by dukwon
Tue May 08, 2018 9:44 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

LPC minutes from yesterday: https://lpc.web.cern.ch/lpc-minutes/2018-05-07.htm Unclear if dumps over the weekend were due to beam intensity. Bunch intensity has been reduced as a precaution. Crossing angle and β* anti-levelling as standard in each fill. The latter causes jumps in lumi at IP2 and 8, ...
by dukwon
Mon May 07, 2018 2:17 pm
Forum: The Accelerator
Topic: Looking ahead to LS2 and Run 3
Replies: 2
Views: 73

Looking ahead to LS2 and Run 3

Plans for LS2: Slides from https://indico.cern.ch/event/705545/attachments/1613081/2562222/Chamonix_Summary_Fk_Bordry_7_March_2018.pdf [media]https://imgur.com/a/1zh32kE[/media] [media]https://imgur.com/a/9cq0cAy[/media] Prospects for Run 3: https://lhc-commissioning.web.cern.ch/lhc-commissioning/pe...
by dukwon
Mon May 07, 2018 6:47 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

Screenshot from 2018-05-07 08-41-10.png
Screenshot from 2018-05-07 08-41-43.png
ATLAS and CMS lumi:
Screenshot from 2018-05-07 08-41-27.png
LHCb lumi:
IntegratedLumiLHCbTime_Yearly.png
IntegratedLumiLHCbTime_Yearly.png (28.82 KiB) Viewed 228 times
by dukwon
Sat May 05, 2018 12:11 pm
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

Stable beams with 2556b. Intensity ramp is finished. Now we're really in full swing. :clap:
lhc1.png
by dukwon
Thu May 03, 2018 10:16 pm
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

2319b fill at the moment. There is a 2460b step before 2556b beams. Looks like they're just doing 1 fill per step now. LHCb is finally getting at least 400 Hz/μb. Loss spikes around 16L2 are dramatically reduced in both beams.
by dukwon
Thu May 03, 2018 10:25 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

The threshold of 1200 bunches, which is considered significant in terms of data taking, was expected to be reached around 11 May, but it was already reached on 28 April. A revised 2018 LHC schedule, which takes into account the faster than anticipated commissioning, has been approved and published,...
by dukwon
Wed May 02, 2018 8:10 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

16L2 news: a combination of a bump and controlling the corrector current have dramatically reduced the loss spikes at 16L2 for B2. They are currently doing the same for B1, but it will only be effective until halfway through the squeeze. B2 is also behaving weirdly: a larger satellite population, de...
by dukwon
Wed May 02, 2018 5:02 am
Forum: The Accelerator
Topic: 2018 Operation
Replies: 46
Views: 2248

Re: 2018 Operation

I don't quite see how they can go to 2556 bunches if the max luminosity is limited to 2.0\nb/s.
There are more ways to control luminosity than number of colliding bunches. All IPs have routinely used levelling since last year.