Page 10 of 13

Re: 2011 Events Discussion

Posted: Mon Jun 27, 2011 4:31 pm
by DCWhitworth
conrad wrote:In the last 24 hours there were 5 successful fills for physics. The average run was about 2 hours. Things kept going wrong. Is this just bad luck?
As the machine load starts to get heavier (more bunches) they have less leeway in terms of machine safety so the MPS is very quick to dump the beams at the first sign of trouble. Of course a lot of analysis then goes into determining if it *was* trouble. A lot of the protection limits have of course been calculated via theory and estimates rather than being based on exact measurements (because there *were* no exact measurements when they were designed). As a result they've been set very conservatively and by careful analysis of the dump events they can determine that they can tune the MPS and safely set the threshold a little bit higher. This is what is happening with UFOs and the recent vacuum spikes they've been having.

So to answer your question, in part yes it's bad luck, but it's also the operators learning about the machine and it's limits.

As I type this there's a long fill going on which I think has just broken the record for single fill integrated luminosity. :dance: Fingers crossed we might actually get a planned dump too !

Re: 2011 Events Discussion

Posted: Mon Jun 27, 2011 8:30 pm
by bgab001
Hi
the current run (1900) looks really nice indeed !
It was just dumped, after more than 20 hours.
And as far as I know it broke several records, with its length and the ~64 pb-1, if I read correctly!

Ben.

Re: 2011 Events Discussion

Posted: Mon Jun 27, 2011 9:12 pm
by Kasuha
... and this time it was programmed dump

... and next fill is physics with 1380 bunches

nice!


Edit: I can see they delayed the dump because there was Booster problem. So that's how records are done :D

Re: 2011 Events Discussion

Posted: Mon Jun 27, 2011 9:23 pm
by DCWhitworth
First programmed dump for more than a month I think.

Re: 2011 Events Discussion

Posted: Tue Jun 28, 2011 12:08 am
by pjotertje
1380 bunches in. :clap:

Re: 2011 Events Discussion

Posted: Tue Jun 28, 2011 1:14 am
by RocketManKSC
Should update schedule link on frame to
https://espace.cern.ch/be-dep/BEDepartm ... hedule.pdf
Thank you

Re: 2011 Events Discussion

Posted: Tue Jun 28, 2011 8:37 am
by pjotertje
RocketManKSC wrote:Should update schedule link on frame to
https://espace.cern.ch/be-dep/BEDepartm ... hedule.pdf
Thank you
Thanks

Re: 2011 Events Discussion

Posted: Tue Jun 28, 2011 9:43 am
by DCWhitworth
DCWhitworth wrote:First programmed dump for more than a month I think.
The morning meeting notes titled it "The fill they couldn't kill" ! :D

Re: 2011 Events Discussion

Posted: Tue Jun 28, 2011 9:01 pm
by jmc2000
Kasuha wrote:... and this time it was programmed dump

... and next fill is physics with 1380 bunches

nice!


Edit: I can see they delayed the dump because there was Booster problem. So that's how records are done :D
The optimum run time is around 7 hours with 2.5 hour turn around. If they could get three of those to run consecutively, then that would be between 80 and 90/pb in 24 hours.

Re: 2011 Events Discussion

Posted: Fri Jul 08, 2011 9:28 am
by Kasuha
Things get always so quiet during technical stops, no progress reports, no news ... anybody knows about "technical stop progress meter" or something like that?

Re: 2011 Events Discussion

Posted: Fri Jul 08, 2011 8:20 pm
by DCWhitworth
The Op elogbook has some details about what's going on but yes it's very quiet.

Re: 2011 Events Discussion

Posted: Sun Jul 10, 2011 10:11 am
by pjotertje
Now whe have a MAJOR electrical power cut. Lost all sectors some patrols and cryo

How long will take before everything is restored?

Re: 2011 Events Discussion

Posted: Sun Jul 10, 2011 11:49 am
by LarryS
The following is from the ops e-log; appears to be a facility wide power hit ...

During the power cut network was switched partly to the Swiss network.

TI is organising electricians to re-establish normal network configuration.

LHC 18 kV loop was lost.

We will only start to reset the machine as soon as electricity is back.

Re: 2011 Events Discussion

Posted: Sun Jul 10, 2011 1:40 pm
by jmc2000
LarryS wrote:The following is from the ops e-log; appears to be a facility wide power hit ...

During the power cut network was switched partly to the Swiss network.

TI is organising electricians to re-establish normal network configuration.

LHC 18 kV loop was lost.

We will only start to reset the machine as soon as electricity is back.
Wow, and they got hit by the same problem in the last week of operation which meant two days without beams. I suppose there is not a lot you can do with a problem like that unless you build a back up generator just to keep the cryogenics operating.

Re: 2011 Events Discussion

Posted: Mon Jul 18, 2011 5:36 pm
by josch222
Dump! Arrgh, shit!, that would have been a record fill.
I saw very short a luminosity something about 1350Hz/┬Áb and they had 100MJ/beam in,
obviously with more bunch intensity than the last fills.
I hope this was not an UFO, they only waited for 1/2h between injection and ramp this
time.