lundi 25 avril 2016

CERN - Preparations continue for the upcoming physics run

CERN - European Organization for Nuclear Research logo.

April 25, 2016

Image above: Low-instensity stable beams were declared in the early hours of Saturday 23 April 2016 (Image: Jacques Fichet/ CERN).

This weekend, CERN's Large Hadron Collider (LHC) moved to the next step in its re-commissioning programme, which started when it took beam for the first time this year, back in March. The operations team declared low-intensity “stable beams”, generating collisions in the experiments.

Image above: First collision event from data taken in 2016 at the ALICE experiment (Image: CERN).

These first stable beams had up to 12 bunches of protons per beam. Each bunch contains around 100 billion protons, moving at almost the speed of light around the 27-kilometre ring of the LHC. They cross each other at the centre of the four big experiments (ALICE, ATLAS, CMS and LHCb).

Image above: Proton proton collision recorded by the ATLAS detector during the LHC 2016 commissioning with low-intensity stable beams. (Image: CERN).

These collisions with low-intensity beams will be used by the experiments to calibrate their detector and to prepare the second run of physics at collision energy of 13 TeV.

After this first phase of collisions with only a few bunches, several days will be devoted to scrub the accelerator’s beam pipes, a necessary step before increasing the number of bunches (the intensity of the beams).

Image above: Commissioning with low-intensity beams helps prepare CMS for this year’s physics run. This event is one of the first collisions recorded in the CMS detector, during the early hours of 23 April 2016 (Image: CERN).

Image above: An event from the LHCb experiment from the first collisions with low-intensity stable beams in 2016 (Image: CERN)

From the beginning of May, the operators will then increase the number of particles circulating in the machine, starting a promising 2016 run. The aim is to increase the number of bunches to 2736 in each beam to deliver huge amounts of data to the experiments. The goal is to provide around six times more data to the experiments than in 2015.


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 articles:

CERN - Too quiet to hear a particle drop:

Return of the LHC – season 2 continues:

Related links:

Large Hadron Collider (LHC):

ALICE experiments:

ATLAS experiments:

CMS experiments:

LHCb experiments:

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

Image (mentioned), Text, Credits: CERN/Corinne Pralavorio/Harriet Kim Jarlett.

Best regards,

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