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The condition for the next step in the number of bunches is 3 complete cycles (going into Physics) and around 20 hours of Stable Beams - hence fills of around 7 hours. Fills will be kept longer once they get into running with a stable number of bunches.

Hi Selina,

Feel free to ask anything you like about the LHC - we will try to answer you

Hi! I would like to achieve better understanding, how the collimators are organized around the machine. When you look at the collimator fixed displays for beam 1 and 2, you can find some rules, but there are too many exceptions from the rules, that it's worth asking :-). 1) In IPs 1,3,5,6 and 7, bo...

The intermediate energy run will be at 2.76TeV (1.38TeV/beam) which is the same center of mass collision energy per nucleon as the Pb run. Lead has 82 protons and 126 neutrons. The run last year was at a proton equivalent energy of 3.5TeV/beam, ie 3.5TeV per proton. The total energy per ion was ther...

The choice of Beta* for Alice and LHCb is optimized for their required luminosities. There is a maximum luminosity that LHCb can cope with - 2-3x10+32. When the potential performance exceeds this, separation will be used to keep the luminosity at around this value. Having a lower Beta* would just me...

Probably to make a new LHC sc-RAP-e ;) There isn't a specific use for the mike data - its more for interest. If the beam did hit the collimator full on you would hear a noise like a gunshot . Sound effects here - http://lhc-collimation-project.web.cern.ch/lhc-collimation-project/sounds%20and%20movi...

Probably to make a new LHC sc-RAP-e

There isn't a specific use for the mike data - its more for interest. If the beam did hit the collimator full on you would hear a noise like a gunshot .

There are microphones attached to some of the collimators.

News of the demise of the hump are greatly exaggerated ... it is still there

It is about a factor of 2 faster than last year when the squeeze was to 3.5m. In addition it goes in one go - last year there was a couple of stops during the squeeze to check things and move the collimators.

The complete squeeze now takes 476 seconds.

The energy is fixed at 3.5 TeV for 2011. During the year there is a plan to develop a method to measure the resistance of the copper splices. If this can be done there would be a campaign of measurements during the next Christmas technical stop. If the values are known then the energy can possibly b...

The collision point for LHCb is displaced with respect to the other experiments. Providing collisions in LHCb therefore means displaced collisions in the other experiments.

The filling schemes are chosen to optimize the number of collisions in all 4 experiments.

Hi At present the bunches are placed in the machine in such a way that they do not collide in the experiments. Imagine 2 cars driving in opposite directions around a racetrack. They will cross in 2 diametrically opposed locations. The LHC can arrange it so that these crossing points occur outside th...

When they are in normal operation for physics the fill number will correspond to a complete machine cycle. For the moment it isn't very important since the machine is in commissioning and just doing studies. The fill number is changed when the guy in charge feels like it.

Hi Unica There are sector valves (sometimes called gate valves) which can be closed in order to split the machines and transfer lines into vacuum sectors. These are normally open. They can be closed manually - for example it is often a routine procedure to close them when giving access to the machin...