Search found 146 matches

by jmc2000
Mon Oct 02, 2017 10:24 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Schedule has been updated: https://beams.web.cern.ch/sites/beams.web.cern.ch/files/schedules/LHC_Schedule_2017.pdf It looks as if they've reallocated two weeks from the proton-proton run to 5 TeV p-p Reference & Low Energy High Beta run. Currently hitting > 3\fb/week so ~ 45\fb for the remaining 7 w...
by jmc2000
Thu Sep 14, 2017 5:30 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Latest 131st LHCC meeting has 45\fb as year end target :
https://indico.cern.ch/event/658856/con ... pt2017.pdf

JMc
by jmc2000
Wed Aug 30, 2017 11:37 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

https://home.cern/cern-people/updates/2017/08/lhc-report-something-nothing "On the basis of current statistics, there appears to be no direct correlation between the number of bunches and the number of beam dumps, so the task force is now planning tests with beams of up to 2200 bunches (last year’s ...
by jmc2000
Tue Aug 29, 2017 6:33 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

So running with the current 1550b yields 0.3\fb/day = 2\fb/week at 55% efficiency giving 35 - 40\fb for 2017 which looks fine to me, bearing in mind that the hope was to accumulate > 100\fb for run 2. I don't see the point in changing the planned running parameters of the LHC significantly, just for...
by jmc2000
Mon Aug 28, 2017 7:06 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Interesting... so am I right in saying that the beam can heat the pipe via inductive heating, thus releasing any frozen gas, and temporary failing of the cryogenics then adds to the problem as the frozen gas is heated? This makes sense because the problem seemed to go away for a while as they gradua...
by jmc2000
Wed Aug 16, 2017 5:21 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

They've moved from 144bpi to 96bpi which looks interesting... perhaps the lower bpi are more efficient in scrubbing the injectors and minimizing loses?

JMc
by jmc2000
Tue Aug 15, 2017 2:33 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Does anyone know why, for the past week, they're having to slowly ramp up the intensity again?

Jmc
by jmc2000
Fri Aug 11, 2017 5:01 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

They were trying for increased bunch intensity, but lost the beam several times upon ramping; so I guess the scrubbing is to "clean" the beam path in the hope this will improve things.

JMc
by jmc2000
Sun Aug 06, 2017 1:05 am
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Atlas currently recording o.5\fb every 13 hours giving >3.5\fb per week for 55% beam time

JMc
by jmc2000
Thu Jul 20, 2017 8:53 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

At one point they managed a new instantaneous luminosity record of 1.65\nb/s, but dumped an hour later because of losses. 1.7\nb/s is the aim this year for beta = 40cm, 1.9\nb/s for beta = 33cm.

JMc
by jmc2000
Tue Jul 04, 2017 1:05 am
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Does anyone know how the MDs went, and if a lower beta is a possibility?

jmc2000
by jmc2000
Tue Jun 27, 2017 6:19 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

No, it looks clearly like BCMS.Emi is around 2.3 like BCMS Lumi is up to 1.55, which could not be achieved with 2460 bunches, if not BCMS. I guess the difference to calculation is due higher crossing angle at start, calculation is for 150µrad, but they start now at 240µrad to lower pile up and decr...
by jmc2000
Mon Jun 26, 2017 11:44 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

https://indico.cern.ch/event/632309/contributions/2556444/attachments/1456855/2250118/LHCC-LHC_machine_status_report_11052017_MSolfaroli.pdf Page 19 gave a few possible 2017 scenarios with 2448b + BCMS giving higher luminosities compared to standard 2736b. We're at a luminosity of around 1.4/nb/s s...
by jmc2000
Thu Mar 09, 2017 11:05 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

Re: 2017 Operation

Summary Session of the LHC Performance Workshop 2017, March 1st:
https://indico.cern.ch/event/614870/

Aim is to record 45\fb, but going by previous years they'll probably go far further: 60\fb? ;)

jmc2000
by jmc2000
Thu Dec 01, 2016 10:46 pm
Forum: The Accelerator
Topic: 2017 Operation
Replies: 72
Views: 5944

2017 Operation

From the recent 128th LHCC Meeting:https://indico.cern.ch/event/580364/, page 27 from LHC Machine Status Report:
Naively applying 2016’s overall Hübner factor gives between 45 and 60 fb-1
Final configuration following discussion at Evian and Chamonix
jmc2000