LHC earned after a year of inactivity

    On November 20, for the first time after 14 months of repair and modernization, CERN specialists launched a proton beam over a large 27-kilometer radius in one direction. This beam was canceled and on November 21 the beam was launched in the opposite direction. The experiment, according to CERN representatives in its microblog , was held in normal mode. After several million test turns in each of the directions, the collider was launched to accelerate the beams in opposite directions simultaneously. All four detectors installed on the LHC successfully record the flow of protons.


    Plans for the remainder of 2009

    Now the LHC accelerates protons to energies of the order of 450 GeV (without the use of large radius accelerators-magnets, because protons accelerate the previous step to this energy - the proton synchrotron). The next stages of CERN's work will be experiments on the collision of protons with an energy of 450 GeV and a test increase in energy to 1.1 TeV, which will probably be somewhere in mid-December ( source 1 , slide No. 3; source 2 ). Energy will not be increased to 3.5 TeV in 2009, in order to maximize the safety of the collider launch process. Around December 17, the collider will be stopped for the Christmas holidays (yes, scientists also have holidays).


    Plans for 2010

    In 2010, it is planned to launch the collider again (January 7). And after preparatory work and checks bring it to a power of 3.5 TeV. After which, 3 months of experiments with protons with an energy of 3.5 TeV (February-May) are planned, an output to energy of 4-5 TeV and 5 months of experiments with an energy of 4-5 TeV (June-October). At the end of the year, the proton beam will be turned off, setting up work with lead ion beams and 1 month of operation in the ion-ion collision mode (November-December).

    It is starting from 3.5 TeV (when two protons collide with such energy that the total interaction energy of 7 TeV is obtained), scientists expect the most “delicious” results of the experiment. Namely, they expect to find new particles participating in the strong interaction (including the Higgs boson). The first data that will be accumulated by the detectors is expected to be processed no earlier than mid-2010. So with the discoveries of new particles, which will still need to be repeated and painstakingly checked, will have to wait a long time.


    One of the problems that exists now and which will need to be solved by CERN specialists is the lifetime of one proton beam. Now it is about 30 minutes. To carry out experiments at maximum energies of 7 TeV, it is necessary to bring it to about 10-12 hours.

    But there is good news. The QPS (Quench Protection System) particle detection and prevention system, the installation of which has been spent 14 months since the last accident in September 2008, is working successfully. During a test run, a proton beam touched one of the magnets. QPS immediately routinely turned off its power supply and removed it from the superconducting state to prevent breakage. A similar incident delayed planned work for about half an hour. However, he showed that the security system is now more perfect, and it will not allow the disabling of magnets, as it was in September 2008 (I recall that the consequence of this accident was the failure of one of the magnets and a ton of liquid helium spilled into the tunnel).

    So we cross our fingers for good luck, and wait for what will happen next.

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