2011 Events Discussion

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Mon Jun 27, 2011 4:31 pm

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 !
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bgab001
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Re: 2011 Events Discussion

Post by bgab001 » Mon Jun 27, 2011 8:30 pm

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.

Kasuha
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Re: 2011 Events Discussion

Post by Kasuha » Mon Jun 27, 2011 9:12 pm

... 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

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Mon Jun 27, 2011 9:23 pm

First programmed dump for more than a month I think.
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pjotertje
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Re: 2011 Events Discussion

Post by pjotertje » Tue Jun 28, 2011 12:08 am

1380 bunches in. :clap:

RocketManKSC
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Re: 2011 Events Discussion

Post by RocketManKSC » Tue Jun 28, 2011 1:14 am

Should update schedule link on frame to
https://espace.cern.ch/be-dep/BEDepartm ... hedule.pdf
Thank you

pjotertje
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Re: 2011 Events Discussion

Post by pjotertje » Tue Jun 28, 2011 8:37 am

RocketManKSC wrote:Should update schedule link on frame to
https://espace.cern.ch/be-dep/BEDepartm ... hedule.pdf
Thank you
Thanks

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Tue Jun 28, 2011 9:43 am

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
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jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Tue Jun 28, 2011 9:01 pm

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.

Kasuha
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Re: 2011 Events Discussion

Post by Kasuha » Fri Jul 08, 2011 9:28 am

Things get always so quiet during technical stops, no progress reports, no news ... anybody knows about "technical stop progress meter" or something like that?

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DCWhitworth
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Re: 2011 Events Discussion

Post by DCWhitworth » Fri Jul 08, 2011 8:20 pm

The Op elogbook has some details about what's going on but yes it's very quiet.
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pjotertje
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Re: 2011 Events Discussion

Post by pjotertje » Sun Jul 10, 2011 10:11 am

Now whe have a MAJOR electrical power cut. Lost all sectors some patrols and cryo

How long will take before everything is restored?

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LarryS
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Re: 2011 Events Discussion

Post by LarryS » Sun Jul 10, 2011 11:49 am

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.

jmc2000
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Re: 2011 Events Discussion

Post by jmc2000 » Sun Jul 10, 2011 1:40 pm

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.

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Re: 2011 Events Discussion

Post by josch222 » Mon Jul 18, 2011 5:36 pm

Dump! Arrgh, shit!, that would have been a record fill.
I saw very short a luminosity something about 1350Hz/µb 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.

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