2017 Operation

The place to discuss the LHC. Commissioning, operation, issues, events ....
mfb
Posts: 163
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2017 Operation

Post by mfb » Mon Jul 31, 2017 8:24 am

10/fb for both ATLAS and CMS. Data-taking makes nice progress, more than 0.6/fb in the last 24 hours.

mfb
Posts: 163
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2017 Operation

Post by mfb » Thu Aug 03, 2017 9:12 pm

Based on the recent MD block, the machine operators are confident that they can go to beta* = 30 cm later (down from 40 cm).

jmc2000
Posts: 141
Joined: Sun May 08, 2011 2:51 pm

Re: 2017 Operation

Post by jmc2000 » Sun Aug 06, 2017 1:05 am

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

JMc

mfb
Posts: 163
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2017 Operation

Post by mfb » Sun Aug 06, 2017 2:21 am

14 hours into the current run, 520/pb.

15.5 weeks of data-taking remaining. If the LHC keeps running as in the last few days, we get 3.5/fb per week and 55/fb more, for a total of more than 60/fb. That is probably too optimistic, but 50/fb doesn't look unrealistic.

jlourenc
Posts: 5
Joined: Wed Apr 27, 2011 4:52 am

Re: 2017 Operation

Post by jlourenc » Fri Aug 11, 2017 3:40 pm

Hi
Can anyone share information about why they’re back to scrubbing (without getting in trouble)?
I haven’t seen any UFO reports.
Thanks
Joao

jmc2000
Posts: 141
Joined: Sun May 08, 2011 2:51 pm

Re: 2017 Operation

Post by jmc2000 » Fri Aug 11, 2017 5:01 pm

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

jlourenc
Posts: 5
Joined: Wed Apr 27, 2011 4:52 am

Re: 2017 Operation

Post by jlourenc » Fri Aug 11, 2017 5:58 pm

Thanks JMc ... keep my fingers crossed so that they reach the 40 ;)
More difficult to understand what’s going on without access to the daily meetings
Best
Joao

jmc2000
Posts: 141
Joined: Sun May 08, 2011 2:51 pm

Re: 2017 Operation

Post by jmc2000 » Tue Aug 15, 2017 2:33 pm

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

Jmc

mfb
Posts: 163
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2017 Operation

Post by mfb » Tue Aug 15, 2017 2:44 pm

They still seem to have problems with beam losses, same point as before.

1.10E11 protons/bunch currently.

Edit Wednesday: Bunch number is oscillating a bit depending on dump reasons, but now we have a stable run with 1550 bunches.

jmc2000
Posts: 141
Joined: Sun May 08, 2011 2:51 pm

Re: 2017 Operation

Post by jmc2000 » Wed Aug 16, 2017 5:21 pm

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

mfb
Posts: 163
Joined: Sat Oct 03, 2015 7:58 pm

Re: 2017 Operation

Post by mfb » Thu Aug 17, 2017 8:53 am

They tried 1940 bunches overnight, dumped again from losses. 1740 worked for a while but then got dumped due to losses as well.

They switched to 96bpi with fill 6072, the night to Saturday, after the scrubbing. It should reduce the heat load, but you can't get 2556 bunches that way.

They tried to fill with 1.25E11 p/bunch before the problems started. That would have been a big step in luminosity.

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