NuMI
Encyclopedia
Neutrinos at the Main Injector, or NuMI, is a project at Fermilab
which creates an intense beam of neutrino
s aimed towards the Soudan Mine for use by several particle physics
experiments. , the MINOS
and MINERνA experiments use the NuMI beam. The proposed NOνA experiment will also use it.
s from Fermilab's Main Injector onto a carbon target. Interactions of the proton beam in the target produce meson
s, primarily pions and kaons, which are focused toward the beam axis by two magnetic horn
s. The mesons then decay into muon
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 MINERνA and the MINOS near detector on site at Fermilab, then through the Earth to the MINOS far detector cavern in the Soudan Mine 735 km away, then onwards into space.
experiment, MINOS is sometimes conflated with NuMI. For instance, the MINOS webpage is at www-numi.fnal.gov instead of www-minos.fnal.gov.
Fermilab
Fermi National Accelerator Laboratory , located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics...
which creates an intense beam of neutrino
Neutrino
A neutrino is an electrically neutral, weakly interacting elementary subatomic particle with a half-integer spin, chirality and a disputed but small non-zero mass. It is able to pass through ordinary matter almost unaffected...
s aimed towards the Soudan Mine for use by several particle physics
Particle physics
Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...
experiments. , the MINOS
MINOS
MINOS is a particle physics experiment designed to study the phenomena of neutrino oscillations, first discovered by a Super-Kamiokande experiment in 1998...
and MINERνA experiments use the NuMI beam. The proposed NOνA experiment will also use it.
Neutrino production
The first step in the production of the NuMI beam is to direct a beam of protonProton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s from Fermilab's Main Injector onto a carbon target. Interactions of the proton beam in the target produce meson
Meson
In particle physics, mesons are subatomic particles composed of one quark and one antiquark, bound together by the strong interaction. Because mesons are composed of sub-particles, they have a physical size, with a radius roughly one femtometer: 10−15 m, which is about the size of a proton...
s, primarily pions and kaons, which are focused toward the beam axis by two magnetic horn
Magnetic horn
A magnetic horn or neutrino horn is a device used in the production of neutrino beams. It focuses charged particles that will decay into neutrinos so that the resulting neutrino beam is as narrow as possible.- Description :...
s. The mesons then decay into muon
Muon
The muon |mu]] used to represent it) is an elementary particle similar to the electron, with a unitary negative electric charge and a spin of ½. Together with the electron, the tau, and the three neutrinos, it is classified as a lepton...
s and neutrinos during their flight through a long decay tunnel. A hadron
Hadron
In particle physics, a hadron is a composite particle made of quarks held together by the strong force...
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 MINERνA and the MINOS near detector on site at Fermilab, then through the Earth to the MINOS far detector cavern in the Soudan Mine 735 km away, then onwards into space.
Naming
Because of the close relationship between NuMI and the MINOSMINOS
MINOS is a particle physics experiment designed to study the phenomena of neutrino oscillations, first discovered by a Super-Kamiokande experiment in 1998...
experiment, MINOS is sometimes conflated with NuMI. For instance, the MINOS webpage is at www-numi.fnal.gov instead of www-minos.fnal.gov.