Neutrinos at the Main Injector, or NuMI, is a project at Fermilab which creates an intense

beam Beam may refer to: Streams of particles or energy *Light beam, or beam of light, a directional projection of light energy **Laser beam *Particle beam, a stream of charged or neutral particles **Charged particle beam, a spatially localized grou ...

of neutrinos aimed towards the Far Detector facility near Ash River, Minnesota for use by several particle detectors. , the

MINOS In Greek mythology, Minos (; grc-gre, Μίνως, ) was a King of Crete, son of Zeus and Europa. Every nine years, he made King Aegeus pick seven young boys and seven young girls to be sent to Daedalus's creation, the labyrinth, to be eaten ...

, MINERνA and NOνA experiments use the NuMI beam. NOνA home page
retrieved 5 October 2007.

Neutrino production

The first step in the production of the NuMI beam is to direct a beam of

proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...

s from Fermilab's Main Injector onto a carbon target. Interactions of the proton beam in the target produce mesons, primarily pions and kaons, which are focused toward the beam axis by two magnetic horns. The mesons then decay into

muon A muon ( ; from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 '' e'' and a spin of , but with a much greater mass. It is classified as a lepton. As wi ...

s and neutrinos during their flight through a long decay tunnel. A hadron absorber downstream of the decay tunnel removes the remaining protons and mesons from the beam. The muons are absorbed by the subsequent earth shield, while the neutrinos continue through it to the MINERνA,

, and

NOvA A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramati ...

near detectors on-site at Fermilab. The neutrinos then travel through the Earth to the

far detector cavern in the Soudan Mine 735 km away and the

far detector 810 km away at Ash River, MN, then onwards into space.

Naming

Because of the close relationship between NuMI and the

experiment, MINOS is sometimes conflated with NuMI. For instance, the MINOS webpage was at www-numi.fnal.gov instead of www-minos.fnal.gov.

References

{{Neutrino detectors Accelerator neutrino experiments Fermilab Fixed-target experiments