Large Hadron Collider starts up again at the end of March
Scientists at the Large Hadron Collider (LHC) Control Centre are busy testing its systems, getting ready to have the world’s largest and most powerful particle collider operational by the end of this month.
In February 2013, HLC went into shutdown to prepare it for higher energy and luminosity. When it becomes operational it will have double its 2013 maximum energy capacity.
At CERN (Conseil Européen pour la Recherche Nucléaire – European Council for Nuclear Research), a European research organization that operates the particle collider, a series of accelerators boosts ions or protons to successively higher energies until they are injected into the LHC. The particles are further accelerated by the LHC before delivering collisions to the four detectors, ATLAS, ALICE, LHCb and CMS.
Beams will not be circulating all the way around the LHC during the tests. They will just reach points 3 and 6. (Image: Leonard Rimensberger/CERN)
The second-to-last accelerator in the chain – the Super Proton Synchrotron (SPS) – is a machine almost 7 kilometres (4.35 miles) in circumference, which receives particles from the Proton Synchroton at 26 GeV, and boosts them to the 450 GeV required for injection into the LHC.
The LHC control team is currently testing the injection systems to make sure that the approaching startup of the accelerator runs as smoothly as possible.
Beams won’t go all the way round yet
Even though particles will be injected into the LHC during this weekend, there will not be any fully circulating beams until the end of this month.
“We will do two tests. Beam 1 will pass through the ALICE detector up to point 3, where we will dump the beam on a collimator, and for Beam 2 we will go through the LHCb detector up to the beam dump at point 6.”
A bright dot appearing on a screen placed in the beam pipe will register a successful pass. The scientists will also monitor other parameters, including the timing of the kickers – fast-pulsing dipole magnets that literally ‘kick’ the beam into the accelerator – and the beam’s path in the injection lines and LHC beam pipe.
Head of the operations team, Mike Lamont, said:
“This test really is a massive debugging exercise. We’ve already pre-tested all the control systems without beam. If the beam goes around we’ll be happy!”
The team is carrying out LHCb and ALICE experiments to prepare their detectors to receive the pulses of particles.
A “splash event” in the LHCb detector, recorded during a 2009 injection test. (Image: LHCb)
ALICE physicist Despina Hatzifotiadou, said:
“ALICE will receive muons originating from the SPS beam dump. They will be used for trigger timing studies and to align the muon spectrometer.”
LHCb will also be gathering data. Patrick Robbe of LHCb said “These tests create an excellent opportunity for us to commission the LHCb detector and data-acquisition system. The collected data are also invaluable for detector studies and alignment purposes, that is, determining the relative geometrical locations of the different sub-detectors with respect to each other. It’s exciting because the tests show that we are getting closer and closer to the restart!”
According to Suykerbuyk, there is still a great deal of work to do before first circulating beams. “We have to finish all the powering tests and magnet training as well as test all the other hardware and beam-diagnostic systems.”
March will be a very busy month for the CERN team.
CERN Video – LHC Preparing to Restart