LHC First Collisions: Thursday Scheduled

[Vanadium 50]

The present LHC schedule has first collisions scheduled for Thursday.

 

[Vanadium 50]

A transformer at point 8 failed. No beam until Wednesday. This makes Thursday collisions unlikely.

 

[K.J.Healey]

Some questions maybe some of you can answer:
At what energy level and intensity are the first collisions supposed to occur?

At which sites are they going to be recorded first for calibration purposes, or will everyone start taking data all at once?

Are all sites ready?

I assume with all the different experiments set up there must be preference for calibration.

 

[Vanadium 50]

The first collisions are at injection energy, 450 GeV on 450 GeV. There will be 2 bunches per beam, with one collision at Point 1 (ATLAS) and another at Point 5 (CMS). Luminosity is anyone's guess - mine is about 10^27 /cm2/s which is about one millionth of design and corresponds to an interaction rate of around 40 Hz.

Within about a month, the hope is that there will be collisions at 5 TeV on 5 TeV at 10^31 or so - about 1% of design. This run's total delivered luminosity is expected to be about 1% of what the Tevatron has collected so far, within maybe a factor of 3 or 4 each way. There will then be a shutdown for several months, and when they come up again in 2009, the hope is that they will be at full energy and will work there way up to design luminosity.

 

[A/4]

Is the schedule posted online anywhere? I searched the LHC website, but couldn't find anything specific.

 

[Vanadium 50]

I don't think the entire schedule is posted anywhere. There's the long term plan (months), which is reported to the experiments by CERN management, and there's a short term plan (one or two days) on the LHC operations web site. But to pick a date in October and say that's when there will be collisions is premature: sure, one could pick a date, but depending on experience it will be bound to change.

 

[ZapperZ]

The 450 GeV first collision has been rescheduled for this Sunday.

Zz.

 

[hgwells]

Yes i think they continuously proceed with testing. The dates like 10 september or 21 october are just "media-days". I think after their official launch of 10 september, there will be less interest from the media. But indeed, the most interesting moment will be when the first collissions take place. They are very cautious that nothing goes wrong this time ... I wonder what energies will be necessary to desintegrate the protons and when this will happen...

 

[Vanadium 50]

Quench in sector 3-4 today. That will delay collisions a few more days minimum.

 

[George Jones]

Quench in sector 3-4 today. That will delay collisions a few more days minimum.

See Cosmic Variance

http://cosmicvariance.com/2008/09/19/lhc-first-magnet-failure/

and BBC

http://news.bbc.co.uk/2/hi/science/nature/7626256.stm.

 

[George Jones]

It seems that the LHC will down for at least two months,

http://www.cnn.com/2008/TECH/science/09/20/hadron.collider.damage.ap/index.html .

Won't this take it into the winter shutdown?

 

[Jimmy Snyder]

LHC damaged by black hole. Earth next.

It looks like the Earth has been spared for another 2 weeks.
http://www.msnbc.msn.com/id/26802846"

 

[George Jones]

It looks like the Earth has been spared for another 2 weeks.
http://www.msnbc.msn.com/id/26802846"

CNN says at least another two months,

https://www.physicsforums.com/showthread.php?p=1880856#post1880856.

 

[Jimmy Snyder]

CNN says at least another two months,

I fat fingered the 'weeks' key. This is bad news. It means I'll have to meet my deadlines after all.

 

[ZapperZ]

I fat fingered the 'weeks' key. This is bad news. It means I'll have to meet my deadlines after all.

Er.. you definitely will have to meet your deadline. Even if they get first collision, it is at such a low energy, it is well below those done right now at the Tevatron. No black there yet last time I checked. It will take a while (a long while) before they get to optimum condition.

Zz.

 

[hgwells]

Well , seems to match the scedule of the maya's too...

 

[Vanadium 50]

Here is the official statement:

Incident in LHC sector 34

Dear Colleagues,
During commissioning (without beam) of the final LHC sector (sector 34) at high current for operation at 5 TeV, an incident occurred at mid-day on Friday 19 September resulting in a large helium leak into the tunnel. Preliminary investigations indicate that the most likely cause of the problem was a faulty electrical connection between two magnets which probably melted at high current leading to mechanical failure. CERN's strict safety regulations ensured that at no time was there any risk to people.

A full investigation is underway, but it is already clear that the sector will have to be warmed up for repairs to take place. This implies a minimum of two months down time for the LHC operation. For the same fault, not uncommon in a normally conducting machine, the repair time would be a matter of days.


Further details will be made available as soon as they are known.

The long-term schedule implications are not obvious - this may actually bring the machine to full energy quicker. If you recall, the reason that the first high energy collisions were to be at 10 TeV rather than 14 TeV was that the magnets needed about two months of additional training. Well, for 7/8 of the ring, a two month window just opened up. It may even by wise to do this now, and try and trigger a similar incident if there are other magnets that may potentially fail in the same way. You'd rather cool down two sectors in parallel instead of one after the other.

 

[Q_Goest]

Hi Vanadium,

Quench in sector 3-4 today. That will delay collisions a few more days minimum.

Do you know if the quench and the helium leak are related? Do you have any more detail on the helium leak? Sounds like the helium actually came out through the vacuum jacket somehow and got into the tunnel.

Also, do you know if the magnets were ramped up to full field prior to the quench? Seems odd that a magnet would spontaneously quench. Most quenches occur only during ramping.

 

[Vanadium 50]

The quench occurred during ramping tests to 5 TeV. Obviously for helium to be leaking there was damage to at least one magnet.

 

[marcus]

Here is the official statement:
...
...
The long-term schedule implications are not obvious...

New official statement just came out (Tuesday)
http://blogs.uslhc.us/?p=388

restart "early spring 2009"

 

[Coin]

I am curious whether this means the winter upgrades will begin early, as the USLHC writers keep predicting.

On the bright side, the first LHC data will be at full power!