CNGS
The CNGS experiment (CNGS stands for English CERN neutrinos to Gran Sasso ) was a physical experiment to neutrino oscillations . For this purpose, from July 2006 to December 2012, neutrinos were generated at the research center CERN and examined in the distant detectors OPERA and ICARUS .
Layout and function
At the SPS accelerator of the research center CERN in Geneva one was neutrino beam produced, which then km over a distance of 730 through the interior of the Earth to the Gran Sasso Laboratory in Italy reached and there in the course of OPERA and ICARUS was detected experiments.
To generate the beam, protons with an energy of 400 GeV are shot at a graphite target in a helium-filled container. The resulting positively charged pions and kaons are then focused into a parallel beam by a magnetic lens system and then disintegrate into muon neutrinos and muons in a 1 km long evacuated tube . The resulting neutrinos keep their flight direction to the Gran Sasso laboratory, while the remaining protons, pions and kaons are caught by an iron / graphite shield. The muon current, which crosses the shield in the same way as the neutrinos, is then measured in order to determine the number of neutrinos emitted. Eventually the muons are also absorbed by the rock and only the neutrinos continue their journey.
It is expected that some of the muon neutrinos will transform into other types of neutrinos (almost exclusively tau neutrinos), which will then be detected by the OPERA detector. This evidence would mean an experimental confirmation of the neutrino oscillation as well as its quantitative investigation.
history
The start of the experiment was originally planned for May 2006; after leaks in the hydraulic systems, the first two weeks of radiation activity took place in October 2007.
In September 2011 OPERA announced that statistical analyzes of measurements between 2009 and 2011 suggest that neutrinos can move faster than light. However, this measurement was erroneous and new measurements have shown agreement with the speed of light. See Neutrino Velocity Measurements for more details .
The neutrino beam was produced for the last time in December 2012.
Web links
Individual evidence
- ↑ a b "CERN Neutrinos to Gran Sasso" (accessed on August 24, 2017)
- ↑ J.Wenninger: CNGS Extraction and Transfer Stability in 2007 (PDF; 8.4 MB), accessed on November 20, 2013