CERN - European Organization for Nuclear Research logo.
July 31, 2013
The ALICE experiment at CERN specializes in heavy-ion collisions at the LHC, which can produce thousands of particles. In analysing this maelstrom, the researchers need to know exactly how material is distributed in the detector - and it turns out that the LHC's simpler proton–proton collisions can help.
A gamma-ray view of the layers of the ALICE detector. (Image: ALICE)
Gamma-rays produced in the proton–proton collisions, mainly from the decays of neutral pions, convert into pairs of electrons and positrons as they fly through matter in the detector. The origin of these pairs can be accurately detected, providing a precise 3D image that includes even the inaccessible innermost parts of the experiment. The process is almost exactly the same as in 1895 when Wilhelm Röntgen produced an X-ray image of his wife’s hand – the inner parts of the body could be seen for the first time without surgery. The main difference lies in the energy of the radiation – ten times greater for the gamma rays in ALICE than for Röntgen’s X-rays. Importantly for the ALICE experiment, it allows the team to check crucial simulations.
Read more: "ALICE through a gamma-ray looking glass" – CERN Courier: http://cerncourier.com/cws/article/cern/54018
Note:
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.
For more information about European Organization for Nuclear Research (CERN), visit: http://home.web.cern.ch/
Image (mentioned), Text, Credits: CERN / Christine Sutton.
Greetings, Orbiter.ch