New neutrino source for the study of solar neutrino physics in the vacuum-matter transition region

Abstract

Production of a neutrino source through proton induced reaction is studied by using the particle transport code, GEANT4. Unstable isotope such as 27 Si can be produced when 27 Al target is bombarded by 15 MeV energetic proton beams. One of the future open issues related to the vacuum-matter transition region in the solar neutrino physics is the determination of the electron-neutrino survival probability P(ν e → ν e ) in that region [14], which is also closely related to questions such as existence of sterile neutrinos [15,16] and/or the non-standard neutrino interactions (NSI) [17], roles of CNO cycle in the Sun (metallicity problem) [18, 19], etc.For this reason, it becomes of importance to detect in detail the solar neutrino in the transition region. Moreover, it would be more efficient if we have the controllable neutrino source in the energy region, which may enable us to extract both the total number and the energy distribution of neutrinos in a more accurate way, with the more elaborate detection system. In this work, we propose an accelerator based new artificial electron-neutrino source for the experiments of the vacuum-matter transition region. By adjusting the incident proton energy, we can produce a specific unstable isotope as an efficient electron-neutrino source. Unstable isotope, 27 Si, is our main neutrino source, which can be produced through 27 Al(p,n) 27 Si reaction and emits electron-neutrinos through radioactive decay processes. In this case, the neutrinos can have the energy similar to the transition region.We outline the paper in the following way. In Sec. II, we summarize the simulation method used in this work. Benchmarking simulations for 27 Al(p,n) 27 Si reaction, calculations for 27 Si yields and energy spectra of electron-neutrinos from decay of 27 Si are presented in 3 Sec. III. Electron-neutrino detections, event rate of the scattered electron and possibility of detecting the sterile neutrino are discussed in Sec. IV and V, respectively. The summary is given in Sec. VI. II. SIMULATION METHODAs an electron-neutrino source, we consider 27 Si isotope in this work, which can be produced through 27 Al(p,n) 27 Si reaction with a threshold energy E th of 5.803 MeV. To evaluate 27 Si yields produced by proton beams on 27 Al target, we use the particle transport code, GEANT4 (GEometry ANd Tracking) v10.1 [20, 21], which is a tool kit that allows for microscopic Monte Carlo simulations of particles interacting with materials.For proton inelastic scattering, four different hadronic models such as "G4BertiniCascade" [22], "G4BinaryCascade" [23], "G4Precompound" [24] and "G4INCLCascade" [25] are available in GEANT4 (v10.1). To check the validity of the models, we first perform simulations of 27 Si production by p + 27 Al reaction and compare the calculated results with the experimental data taken from the EXFOR database [26]. For brevity, we refer to GEANT4 simulations with "G4BertiniCascade", "G4BinaryCascade", "G4Precompound" and "G4INCLCascade" as "G4BERTI", "G4BC", "G4PRECOM" and "G4INCL", ...

High-power Fixed-Field Accelerators

“…This was proposed in ref. [173] for an accelerator-based study of the vacuum-matter transition region relevant for solar neutrino experiments using a radiochemical detector located 10 m from the target. However, we are most interested in developing this as a potential upgrade for DUNE, since the threshold for 𝜈 𝑒 + 40 Ar→ 40 K * + 𝑒 − is 1.5 MeV.…”