Towards the optimal energy of the proton driver for a neutrino factory and muon collider

TL;DR

This study analyzes pion production data to determine the optimal proton beam energy for neutrino factories and muon colliders, finding a maximum yield around 7 GeV with a broad effective energy range.

Contribution

It provides a data-driven assessment of the optimal proton driver energy for neutrino and muon collider facilities, incorporating thick target effects and experimental corrections.

Findings

Maximum muon yield at about 7 GeV beam energy.

Yield remains within 10% of maximum for 4-11 GeV.

Yield within 20% of maximum down to 2 GeV.

Abstract

Cross section data from the HARP experiment for pion production by protons from a tantalum target have been convoluted with the acceptance of the front-end channel for the proposed neutrino factory or muon collider and integrated over the full phase space measured by HARP, to determine the beam-energy dependence of the muon yield. This permits a determination of the optimal beam energy for the proton driver for these projects. The cross section data are corrected for the beam-energy dependent amplification due to the development of hadronic showers in a thick target. The conclusion is that, for constant beam power, the yield is maximum for a beam energy of about 7 GeV, but it is within 10% of this maximum for 4<Tbeam < 11 GeV, and within 20% of the maximum for Tbeam as low as 2 GeV. This result is insensitive to which of the two HARP groups' results are used, and to which pion generator is used to compute the thick target effects.