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The CNGS project
Compared to natural sources, an accelerator-based neutrino beam offers the advantage of a higher flux and of a high purity of nu_mu with known and small contaminations of other flavours. The CNGS (Cern Neutrino beam to Gran Sasso) facility (Fig. 1 and 2) from the CERN-SPS to the Gran Sasso Laboratory is planned to deliver a nu_mu beam from 2006 onwards. In its present design, the beam is optimized for a nu_tau appearance search for the experiments OPERA and ICARUS.
To produce the muon neutrinos the CERN-SPS protons hit a graphite target made of rods, with an overall target length of 2m, producing secondary pions and kaons. The pions and kaons are focused by two coaxial magnetic lenses, the horn and the reflector, are then directed towards a 1km long decay tunnel to produce the neutrino beam which travel over a distance of 732km to the Gran Sasso laboratory in Italy. The RMS of the beam size at Gran Sasso where the OPERA detector is located is about 800m. The mean energy of the nu_mu beam is 17GeV and the production rate is 7.45x10-9/pot (pot = proton on target). This yields to a nu_mu CC production rate of 5.44x10-17/pot/kton in the OPERA detector.
read more: Physics motivation
read more: The OPERA detector
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Fig. 1: CNGS
(© CERN)
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Fig. 2: CNGS
(© CERN)
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Fig. 3: CNGS Structure (© CERN)
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