Simulation of a first case study for magnetic field imaging with the Magic-$\mu$ technique

TL;DR

This paper demonstrates the feasibility of using cosmic-ray muons to image magnetic fields by simulating a dipole magnet and analyzing muon trajectories with Monte Carlo methods.

Contribution

It introduces a novel application of muography for magnetic field imaging and validates it through detailed simulation of muon interactions with a dipole magnet.

Findings

Magnetic fields influence muon trajectories as shown in simulation.

Count rate maps differ significantly with magnetic field on and off.

The method shows promise for non-invasive magnetic field imaging.

Abstract

So far, most of the developments in muography (or cosmic-ray muon radiography) have been based on either the scattering or the absorption of cosmic-ray muons produced by the nuclear interactions between primary cosmic-rays and the nuclei of the Earth's atmosphere. Applications of muography are increasing in various disciplines. A new use of this technique to measure a magnetic field has recently been proposed by our group. This new application takes advantage of the electric charge of cosmic-ray muons, which causes them to change their trajectory due to the Lorentz force generated by a magnetic field. In this study, we present a feasibility study of the proposed technique by simulating a simple dipole magnet using the three-dimensional finite element solution package AMaze, together with the PHITS Monte Carlo simulation tools. The distribution of magnetic field flux densities around the magnet was calculated in AMaze and entered into the PHITS code. Positive and negative cosmic-ray muons were generated based on the PHITS-based analytical radiation model (PARMA). A comparison of the count rate maps of the detected muons on two position-sensitive scintillator detectors for the magnetic field ON and OFF was studied using PHITS. The simulation results show the effect of the magnet on the count rate maps and are promising for the newly proposed application of cosmic-ray muons, the imaging of a magnetic field.