mardi 10 mars 2015

CERN - Injection tests make a splash

CERN - European Organization for Nuclear Research logo.

March 10, 2015

On Saturday 7 March, two of the LHC experiments saw proton beams for the first time after a two-year stop. Beam 2 (anticlockwise) made it through LHCb at 10.30 and Beam 1 (clockwise) passed through ALICE at 17.00. The two experiments were switched on to record so-called splash events, particles emerging from the collision between the proton beam and a block positioned to stop the beam. The proton beams passed through three of the eight sectors of the LHC machine – slightly more than 10 km of the 27 km ring.

The splash events recorded by the LHCb (left) and ALICE experiments(right)

“The tests were a big a success – on the one hand because we made it successfully to Point 3 with Beam 1 and onto the beam-dump block in Point 6 with Beam 2, and on the other hand because we discovered many issues, which we can still fix before we start commissioning with beam”, said Verena Kain, one of the two engineers in charge of LHC operations at the weekend.

An essential first step before a full restart, these injection tests are now being followed by the final stages of the hardware commissioning of the machine at the CERN Control Centre. Commissioning with beam is scheduled to start in the week beginning 23 March.

CERN - The Large Hadron Collider (LHC) 27 km ring annotated


CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

CERN - LHC injector tests to begin:

Timelapse: LHC experiments prepare for restart:

CERN's two-year shutdown drawing to a close:

Large Hadron Collider (LHC):





Super Proton Synchrotron (SPS):

For more information about the European Organization for Nuclear Research (CERN), visit:

Images, Text, Credits: CERN/Paola Catapano.