Record Breaking Run at LHC

Yesterday the Large Hadron Collider completed a physics run lasting 18.5 hours that set two new records for the collider. The peak luminosity reached 3.1 MHz/b and the total luminosity collected was 120/nb, it is the first time they have collected over 100/nb in one run. This takes the accumulated luminosity to about 670/nb. Another similar run is already underway showing that they are now settling in to the routine physics runs they planned for August with 25 on 25 high intensity bunches providing 16 collisions per turn in each experiment (filling scheme multi-25b_16_16_16).

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6 Responses to Record Breaking Run at LHC

  1. Luboš Motl says:

    The MHz/b unit of luminosity is funny, except that because nothing in the collisions is really following a “sine”, the MHz seems strange for the inverse second. 😉 Can’t you simply replace MHz/b by 1/(μb.s)? 🙂

  2. Philip Gibbs says:

    I know, I keep using different units which is confusing. The CERN documentation does it too. It would be more intuitive if there was a standard name for an inverse barn. If we could call it a nrab we could talk of Mega nrabs per second (Mn/s) and say they have collected 700 Giga nrabs (Gn) etc. People are more familiar with Mega, Giga, Tera than micro, nano, pico, especially when talking about something that is getting bigger. But introduing a new unit would be even more silly.

  3. Luboš Motl says:

    Yes, it is inconvenient that the barn has to be inverted. I don’t like your name though.

    What actually happens if you invert a barn, upside down? Well, I think that the corn and cattle falls onto the ground. So one inverse barn is one cow. You meant 3.1 μcow/s. No, sorry, I mean Mcow/s.

    More seriously, I agree that new units are silly – but that’s pretty much why I criticized the MHz terminology, too.

  4. Philip Gibbs says:

    The nrab is not no worse in principle than the mho which is still used in places for the inverse ohm, although the siemens is the official unit named after a German engineering conglomerate 🙂

    MHz/barn is sometimes used in CERN publications. I didn’t make it up!

    I’d even be happy to use you Mcow/s if there were enough people using it to get some traction, but somehow I think not 🙂

  5. Luboš Motl says:

    Cows or nrabs, why don’t we agree to write all future data about the immediate luminosity in units of “inverse femtobarn per year”? There’s a goal of 1/fb by the end of 2011, so this is a very natural unit. We were also told that there would possibly be 3000/fb by 2030 haha.

  6. Philip Gibbs says:

    1/μb/s = 0.0316/fb/yr I think.

    It does give a good idea of how far they have to go, but it is hard to match with units used on the CERN displays. I might use both units at the same time where appropriate.

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