Ao Liu

A FODO racetrack ring for nuSTORM: design and optimization

The goal of nuSTORM is to provide well-defined neutrino beams for precise measurements of neutrino cross-sections and oscillations. The nuSTORM decay ring is a compact racetrack storage ring with a circumference of ∼480 m that incorporates large aperture (60 cm diameter) magnets. There are many challenges in the design. In order to incorporate the Orbit Combination Section (OCS), used for injecting the pion beam into the ring, a dispersion suppressor is needed adjacent to the OCS. Concurrently, in order to maximize the number of useful muon decays, strong bending dipoles are needed in the arcs to minimize the arc length. These dipoles create strong chromatic effects, which need to be corrected by nonlinear sextupole elements in the ring. In this paper, a FODO racetrack ring design and its optimization using sextupolar fields via both a Genetic Algorithm (GA) and a Simulated Annealing (SA) algorithm will be discussed.

Overview of the Neutrinos from Stored Muons Facility - nuSTORM

Neutrino beams produced from the decay of muons in a racetrack-like decay ring (the so called Neutrino Factory) provide a powerful way to study neutrino oscillation physics and, in addition, provide unique beams for neutrino interaction studies. The Neutrinos from STORed Muons (nuSTORM) facility uses a neutrino factory-like design. Due to the particular nature of nuSTORM, it can also provide an intense, very pure, muon neutrino beam from pion decay. This so-called Neo-conventional muon-neutrino beam from nuSTORM makes nuSTORM a hybrid neutrino factory. In this paper we describe the facility and give a detailed description of the neutrino beams that are available and the precision to which they can be characterized. We then show its potential for a neutrino interaction physics program and present sensitivity plots that indicate how well the facility can perform for short-baseline oscillation searches. Finally, we comment on the performance potential of a Neo-conventional muon neutrino beam optimized for long-baseline neutrino-oscillation physics.

Status of the nuSTORM Facility and a Possible Extension for Long-Baseline

Neutrino beams produced from the decay of muons in a racetrack-like decay ring (the so called Neutrino Factory) provide a powerful way to study neutrino oscillation physics and, in addition, provide unique beams for neutrino interaction studies. The Neutrinos from STORed Muons (nuSTORM) facility uses a neutrino factory-like design. Due to the particular nature of nuSTORM, it can also provide an intense, very pure, muon neutrino beam from pion decay. This so-called “Neo-conventional muon neutrino beam from nuSTORM makes nuSTORM a hybrid neutrino factory. In this paper we describe the facility and give a detailed description of the neutrino beam fluxes that are available and the precision to which these fluxes can be determined. We then present sensitivity plots that indicated how well the facility can perform for short-baseline oscillation searches and show its potential for a neutrino interaction physics program. Finally, we comment on the performance potential of the Neo-conventional muon neutrino beam optimized for long- baseline neutrino-oscillation physics.

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The stochastic injection scenario used by nuSTORM features the pion decay and secondary muon acceptance in the storage ring’s long decay straight [1,2]. The designed momentum acceptance of the nuSTORM decay ring is centered at 3.8 GeV/c, based on neutrino detector performance, with a

Oscillation Experiments

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Determining the Pion Reference Momentum for nuSTORM Injection Design

10% bin. In order to design the injection section, and to obtain as many useful muons from pion decay as possible, the center momentum of the pion beam being injected needs to be carefully chosen. This paper describes in detail the determination of the center momentum of the pion beam, with simulation from G4Beamline [3].

DESIGN OF THE BEAM COMBINATION SECTION FOR STOCHASTIC INJECTION

The stochastic injection scenario proposed by D. Neuffer in early 1980’s [1] features the injection and acceptance of pions into the muon storage ring, and is used in the design and simulation of nuSTORM injection and ring [2,3]. The pions decay to muons in the long decay straight section of the ring, then the secondary muons are accepted by the straight FODO structure. The critical design element in this scenario is the Beam Combination Section (BCS), which serially includes a defocusing quadrupole, a bending dipole, and a focusing quadrupole. This paper describes in detail the the design of such a BCS and the matching from this BCS to the downstream side of magnetic horn used to collect the pions after target.