LHC portal

Hi,

I think this speaks for itselft:



Peak lumi's been dropping steadily and is now around the peak lumi they got with 912 bunches, though they have more than 100 more in the machine...

The beam currents are a little bit lower, but that's not enough to explain this 20% drop...

Do you have any idea as to the whyness of this problem or how they might correct it? There's not much about it in the daily reports...

Cheers,

Bornerdogge

The beam intensity has been allowed to slip down by nearly 10%. You can see the intensity plots on the statistics page if you click on the fill numbers. https://lhc-statistics.web.cern.ch/LHC-Statistics/ A 10% drop in intensity gives a 19% drop in luminosity because of the square dependency. I think that mostly accounts for it. They can always push the intensity up again.

There has also been some variable amounts of emittance blowup which affects the luminosity, but I dont think this has become worse.

Oh right, thanks, I forgot that L ~ I²...

Was there a particular reason to push the intensity down by 10%? Too many UFOs I guess?