Last 2 turnarounds from dump to physics were less than 3 hours. Theoritical limit is around 2 hours. Good Job!!PhilG wrote: They managed a turnround of only 2.5 hours between runs, much better than last year.
2011 Events Discussion
Re: 2011 Events Discussion
- DCWhitworth
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Re: 2011 Events Discussion
They're smooth operatorssciing wrote:Last 2 turnarounds from dump to physics were less than 3 hours. Theoritical limit is around 2 hours. Good Job!!PhilG wrote: They managed a turnround of only 2.5 hours between runs, much better than last year.
DC
The LHC - One ring to rule them all !
The LHC - One ring to rule them all !
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Re: 2011 Events Discussion
If the turn around time is 2.5 hour look more like 3 hours Physic to Physic. It would appear to a untrained eye that they may be reseting a little early.
Re: 2011 Events Discussion
RocketManKSC, nice analysis although your extrapolation of the luminosity decay seems pessimistic. It should decay exponentially (perhaps faster at the start) The luminosity half life is about 15 hours.
Theoretically the optimum runtime would be roughly 2 x sqrt(L*T) where L is the lifetime and T is the turnround time. If they could average about 3 hours they should run for about 12 hours at least, so yes they are stopping too soon.
However, they are not yet aiming to run at optimum efficiency. The present objective is to meet the qualifying conditions as quickly as possible to allow them to move to the next increase in bunch numbers. I don't know what the conditions are but they may be required to do three runs with a total of 12 hours in stable beams or something like that.
Theoretically the optimum runtime would be roughly 2 x sqrt(L*T) where L is the lifetime and T is the turnround time. If they could average about 3 hours they should run for about 12 hours at least, so yes they are stopping too soon.
However, they are not yet aiming to run at optimum efficiency. The present objective is to meet the qualifying conditions as quickly as possible to allow them to move to the next increase in bunch numbers. I don't know what the conditions are but they may be required to do three runs with a total of 12 hours in stable beams or something like that.
Re: 2011 Events Discussion
The condition for the next step in the number of bunches is 3 complete cycles (going into Physics) and around 20 hours of Stable Beams - hence fills of around 7 hours. Fills will be kept longer once they get into running with a stable number of bunches.
Re: 2011 Events Discussion
pcatom, thanks. I understand that they will increase bunch numbers as 32,64,104,152,200.
Will they go all the way with 8 bunch injections or switch to 24 bunch injection at some point?
If the current smooth running continues they should easily make it to 200 before the next technical stop on 28th March.
Will they go all the way with 8 bunch injections or switch to 24 bunch injection at some point?
If the current smooth running continues they should easily make it to 200 before the next technical stop on 28th March.
Re: 2011 Events Discussion
The next step will be 136 bunches - hopefully this evening. This will use 24 bunch injection (plus a couple of 8 bunch injections).
After that would be around 200 bunches. However, the plan is now to get the 1.38 TeV run out of the way before the technical stop. Expect a change to running like this around Wednesday.
After that would be around 200 bunches. However, the plan is now to get the 1.38 TeV run out of the way before the technical stop. Expect a change to running like this around Wednesday.
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Re: 2011 Events Discussion
Thanks for all your comment and input. This forum is a great place for sharing information.
Hope they can keep up the same production rates in the future. If so will make for a great
year of data collection.
Hope they can keep up the same production rates in the future. If so will make for a great
year of data collection.
Re: 2011 Events Discussion
We are hoping for a much higher production rate ... a factor 15 higher luminosity than at present (64 bunches).Thanks for all your comment and input. This forum is a great place for sharing information.
Hope they can keep up the same production rates in the future. If so will make for a great
year of data collection.
What is impressive is the overall efficiency.
Re: 2011 Events Discussion
They are starting on the 136 bunch fill now. This is an amazing rate of progress.
Re: 2011 Events Discussion
This is a good summary of what has been going on so far at the LHC and the current plan for the weeks ahead. It also give a nod to LHC protal and Pcatom!
http://blog.vixra.org/2011/03/20/lhc-de ... tes-plans/
http://blog.vixra.org/2011/03/20/lhc-de ... tes-plans/
- CharmQuark
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Re: 2011 Events Discussion
New luminosity record of over 2.5x10^32 - peak in 2010 was 2.0x10^32.
Well done guys
Well done guys
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.
- DCWhitworth
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Re: 2011 Events Discussion
Wow, a whole heap of new LHC records have been set this week -
http://lhc-commissioning.web.cern.ch/lh ... 03-11.pptx
http://lhc-commissioning.web.cern.ch/lh ... 03-11.pptx
DC
The LHC - One ring to rule them all !
The LHC - One ring to rule them all !
- Bornerdogge
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Re: 2011 Events Discussion
Does anybody know the purpose of the current 1.38TeV run?
- DCWhitworth
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Re: 2011 Events Discussion
It's calibration for the lead ion runs. Basically they learn a lot by comparing how lead ion collisions differ from proton collisions. BUT no one has ever done proton collisions at the same centre of mass energies they they have been doing lead collisions at so their comparisons are based on modelled extrapolations of proton collisions at lower and higher energies. While the models are pretty good they're not going to be 100% right. So these runs are to produce collision data at exactly the right energies for comparison with the lead ion energies. They don't need much data so these runs won't last very long.Bornerdogge wrote:Does anybody know the purpose of the current 1.38TeV run?
Next up 296 proton bunches at 3.5 TeV
DC
The LHC - One ring to rule them all !
The LHC - One ring to rule them all !