Neutrino Radiation at Muon Colliders and Storage Rings

Abstract

Intense highly collimated neutrino beams, created from muon decays at high-energy muon colliders or storage rings, cause significant radiation problems even at very large distances from the machine. A recently developed weighted neutrino interaction generator permits detailed Monte Carlo simulations of the interactions of neutrinos and of their progeny with the MARS code. Special aspects of neutrino radiation dose evaluation are discussed. Dose distributions in a tissue-equivalent phantom are calculated when irradiated with 100 MeV to 10 TeV neutrino beams. Results are obtained for a bare phantom, one embedded in several shielding materials, and one located at various distances behind a shield. Neutrino radiation is investigated around muon storage rings serving as the basis for neutrino factories. The most challenging problem of offsite neutrino dose from muon colliders and storage rings is studied. The distance from the collider ring (up to 60 km) at which the expected dose rates equals prescribed annual dose limits is calculated for 0.5-4 TeV muon colliders and 30 and 50 GeV muon storage rings. Possible mitigation of neutrino radiation problems are discussed and investigated.

Muon collider interaction region design

“…It will require even stronger SC magnets and will have to address such issues as the neutrinoinduced radiation [22]. …”

Beam-induced radiation in a muon storage ring for a neutrino factory

“…Neutrino-induced radiation downstream of the straight sections is more severe than from the arcs. The off-site limit of is only met after 4.2 km and 1.8 km for 50 GeV and 30 GeV muon storage ring, respectively [5]. The maximum half-width of an off-site limit isocontour is 4.3 m and 2.7 m, respectively.…”

“…Conveniently, power supply rooms and other underground enclosures should be placed on the inward side of the arc tunnel permitting unlimited occupancy even during machine operation. In mars14 calculations, the decay neutrinos are propagated in the code through the dirt surrounding the tunnel, where they interact, and create daughter showers which produce radiation at very large distances [5]. The off-site limit of 10 mR/yr or 0.1 mSv/yr is reached 50 m radially outward from the beam's orbit (Fig.…”

Proposal to perform a high - statisics neutrino scattering experiment using a fine - grained detector in the NuMI Beam

“…The model is described in detail in [195]. Some notable features of the model include: • Recoil of the target is simulated only for elastic interactions.…”