Current Events Discussion
Re: Current Events Discussion
Woopie!!!
- CharmQuark
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Re: Current Events Discussion
Way to go guys!!!!!!!!!!!!!!!!!!
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.
Re: Current Events Discussion
Hi, I see that about 20% of the beam is lost (It started at 2.5E12 and now it is ~2.0E12). Is this caused by collisions? Is it safe to loss this amount of particles?
Thanks
Fernando.
Thanks
Fernando.
Re: Current Events Discussion
A few protons are lost due to collisions with molecules of the imperfect vacuum in the tube, but most are being lost on the collimators as the beam spreads out. So long as the loss rate is not too high that is perfectly safe. The collimators are designed to take the loss and protect more delicate components.
Re: Current Events Discussion
I can see nearly 2,5 10e30cm-2s-1 lumi, is this a new record?
oldboson
oldboson
- DCWhitworth
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Re: Current Events Discussion
It was around about that level yesterday too.
DC
The LHC - One ring to rule them all !
The LHC - One ring to rule them all !
Re: Current Events Discussion
does any one know when live collisions will be veiwable again?
Re: Current Events Discussion
Interesting comment in LHCb log book:
DaveMessage ID: 16934 Entry time: 02-Aug 04:32
Author: Conor Fitzpatrick
Additional amazingness can be seen in the AB & OP logbook- they are seeing the effect of the tides on the beam
energy.
- Bornerdogge
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Re: Current Events Discussion
Nearly every day, just have a look at the "coordination" page on the vistars...tomey36 wrote:does any one know when live collisions will be veiwable again?
By the way, new record today, they've just broken the 3e30 barrier!
- CharmQuark
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Re: Current Events Discussion
Nice work guys
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.
- Bornerdogge
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Re: Current Events Discussion
Does anybody know why they witness such a drop in instantaneous luminosity (50% in a few hours), where the beam intensity stays nearly constant?
- DCWhitworth
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Re: Current Events Discussion
I was wondering that too, I guess the bunches start to spread out over time so making collisions less likely and hence luminosity lower.Bornerdogge wrote:Does anybody know why they witness such a drop in instantaneous luminosity (50% in a few hours), where the beam intensity stays nearly constant?
DC
The LHC - One ring to rule them all !
The LHC - One ring to rule them all !
Re: Current Events Discussion
Also luminosity is proportional to (intensity)^2, so you would expect it to drop faster.Does anybody know why they witness such a drop in instantaneous luminosity (50% in a few hours), where the beam intensity stays nearly constant?
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Re: Current Events Discussion
I observe a rapid decline at the same time as tune and orbit feedback are turned off at declaration of stable beams. Comments from the enlightened?
And every collision (or grazing contact) kills some protons, plus losses at the collimators and beam gas events cut down the available participants. It seems they start with an instantaneous luminosity of almost 3 units and let it decay down to about 1 unit after 14 hours or so then dump and do a refill.
So 4 am Friday till 7 pm physics, reset 7pm till 1:42 AM sat 1:42 stable beams again.
Almost routine.
And every collision (or grazing contact) kills some protons, plus losses at the collimators and beam gas events cut down the available participants. It seems they start with an instantaneous luminosity of almost 3 units and let it decay down to about 1 unit after 14 hours or so then dump and do a refill.
So 4 am Friday till 7 pm physics, reset 7pm till 1:42 AM sat 1:42 stable beams again.
Almost routine.
Re: Current Events Discussion
It is just a guess, but it could be that some protons are "better" at colliding than others.
If that is the case, the "good" ones would be the ones to go first, so that the quality of the beam quickly deteriorates, and that luminosity drops as a result.
If that is the case, the "good" ones would be the ones to go first, so that the quality of the beam quickly deteriorates, and that luminosity drops as a result.
- Tau