LHC portal

Exciting times indeed!

Already made it to 6.8 TeV this morning, and after a little cryo glich, we're on our way squeezing down to beta*=30cm!

First Stable Beams @ 1.2m -> 30cm!

Now for the intensity ramp-up...

First collisions at low-beta* - 1.2m.

Followed by the first beta* levelling with colliding beams from 1.2m down to 30cm in ATLAS and CMS.

The actual lumi target (25 fb-1, the dashed orange line) was not modified. However, with the long downtime in September, the schedule was updated, basically considering the period as a technical stop. Following that, the lumi prediction (green line) was re-generated with the new schedule. In any cas...

After a few rocky attempts, yesterday evening the VELO was fully closed - congratulations LHCb!
Also, finally the 8b4e+BCMS hybrid filling scheme (a mix of 8b4e and "normal" bunch trains) was successfully tested, this could allow pushing the bunch intensity higher.

Back to a full machine with 2461 bunches!
Electron cloud is still the main limiting factor, but there is some margin to push the bunch intensity a bit higher.

The 180bpi is trains of 5*36 bunches while the 240bpi is 5*48 bunches. The shorter train length helps to reduce electron cloud buildup, which in turn allows increasing the intensity per bunch. Compared to the fill before the heat load is ~10% lower for the same total intensity. Screenshot from 2022-...

I think it's been permanently disabled, possibly because the public have increasingly lost interest in having access to it, It's somewhat simpler, unlike many of the other Vistars the "Dashboard" is not really used in daily operation, and it is built on a different technology that never followed th...

The "outliers" are recent quenches in S56 :-) But clicking on these plots will replace the image by a fully interactive version where you can zoom in, inspect, etc. On the cryo plot you won't see much of the head load though, as the temperature is actively regulated - the extra heating just puts mor...

I guess you are talking about slow losses (beam lifetime), not fast/UFO losses. There is a couple of effects that drive these. To stabilize the beams in the presence of e-cloud, we currently need strong non-linearities (chromaticity and octupoles), which are detrimental to lifetime. Also e-cloud can...

Indeed, let me put it that way - there is contingency in the schedule to anticipate problems during the commissioning. We were 1-2 weeks ahead at times, most of which has been "lost back" in the meanwhile. The RF holds for the moment, but the problem will need to be investigated further next week. D...

Yes, a bit behind the initial schedule due to the various problems, including 8 training quenches during operation, 1 UFO/beam induced quench and some trouble with the RF. UFO rates at the beginning of the run were back to the levels of early 2015, clearly de-conditioning w.r.t. the end of Run 2, bu...

That was definitely not the best moment to get a training quench, but we all know Murphy's law.
In the end, while we used up all the contingency, all went fine. Collisions, Stable Beams, followed by a nice ~8h fill with 3x3 bunches.

LHC is back in physics!

Stable Beams at 450 GeV!

Also, this times all 4 IPs are really colliding, with LHCb measuring a luminosity signal for the first time with the all-renovated detector!

Yes, there will surely be a big media event - by coincidence (or not quite...), the 10th anniversary of the Higgs discovery also falls into the same time period.

And the nominal bunches just made it up the ramp to 6.8 TeV!