LHC portal

I find it very sad the way some scientists and the press especially are jumping to the conclusion that neutrinos are travelling faster than the speed of light. It's as if... they want it to be true. No, sorry, mother nature doesn't work like that and the speed of light remaining a speed limit will b...

Nice report and well may the LHC team be pleased with themselves and the machine :D 10/fb for next year still seems a tall order, but I suppose possible with 1.5/fb, 2/fb, 3/fb, 4/fb for the 4 periods. It's astonishing the way they've tamed the beast over the past year and I wouldn't put it past the...

adam_jeff wrote:I could just add that in the loss map, the red marks represent the dump threshold or maximum allowed losses for each of the monitors. If the losses (green bars) reach the red mark at any point, the beam will be dumped.

So what are the blue bars?

On fill 2109 they're going for a bunch intenstiy of 1.4x10^11 protons per bunch which seems way higher than 1.2x10^11 last week. So how high can they go?

For the final run they're using a value of beta* = 1.0m which should increase the luminosity by a factor of 1.5 and more new records, hopefully

the LHC dashboard claims the beam will be back tomorrow afternoon - how?" Keeping these messages up to date is not their primary concern. It's just 'operator chat', important information goes through different channels. Well I can't comment since I don't have direct access to what their policty is ...

pjotertje wrote:Problems with sector 45 again

Yes, and I was just about to the ask a question: " Sector 45 is not showing any indication of cooling down right now, yet the LHC dashboard claims the beam will be back tomorrow afternoon - how?"

If there is power cut causing an upset for the cryogenics, what must be done to bring it back onlline when the power returns?

Over the past 8 days, the operation of the LHC has taken a hammering with a day off to replace the SPS magnet, 4 for the failure of the cyogenics, and another 2 because of the power cut. So that makes a loss of a week out of 6 for this segment.

What's been a similar bad period post 2010?

And another record Fill #2006 One minute shy of 26 hours with over 100 (pb)^-1 integrated luminosity. http://lhc-statistics.web.cern.ch/LHC-Statistics/index.html# String 10 of those together and there's another inverse femto-barn! Getting 3/fb looks on the cards over the next 2 weeks - what an achi...

For each inelastic collision with a chance to provide recordable physics data there are thousands of elastic collisions in which protons just "bounce" off each other and eventually get lost from the beam - there's no way around it, beam gets used up during physics. Well, maybe it's more dependent u...

I've notiiced that as they've increased the instantaneous luminosity, the half life is reduced: At 1/nb/s it was around 20 hours giving 60/pb/20hours; at 2/nb/s it's 14 hours giving 90/pb/20hours. So for a fixed peak luminosity, how can they increase the luminosity half life? If they can't do anythi...

looks like they did manage 2000/ubs good stuff! Record Peak luminosity is now around 2050 ub-1s-1 And looks as if the machine is tuned to perfection right now, managing a turn around after an electrical glitch of just 2 hours, and a integrated luminosity within 24 hours of over 100/pb. I'm amazed t...

Hey thanks for the links!

I'd expect Beta* to be between 1.0 and 1.5m, but a value of 10m is shown on this page http://op-webtools.web.cern.ch/op-webtools/vistar/vistars.php?usr=LHCCONFIG Can someone explain the difference? Aha! it drops down to 1.5m when squeezing the beam. But how on earth are they getting luminosities of...