Radiation and thermal analysis of production solenoid for Mu2e experimental setup

TL;DR

This paper analyzes the radiation and thermal behavior of the Mu2e production solenoid, using simulations to optimize absorber design for reliable superconducting magnet operation in a high-radiation environment.

Contribution

It presents a detailed radiation and thermal analysis of the Mu2e production solenoid, including absorber optimization and simulation results for energy deposition and cooling.

Findings

Absorber design reduces neutron flux entering coils by 3 orders of magnitude.

Simulation results inform the thermal management and safety margins of the superconducting magnets.

Optimized absorber performance balances cost and effectiveness.

Abstract

The Muon-to-Electron (Mu2e) experiment at Fermilab, will seek the evidence of direct muon to electron conversion at the sensitivity level where it cannot be explained by the Standard Model. An 8-GeV 25-kW proton beam will be directed onto a tilted gold target inside a large-bore superconducting Production Solenoid (PS) with the peak field on the axis of ~5T. The negative muons resulting from the pion decay will be captured in the PS aperture and directed by an S-shaped Transport Solenoid towards the stopping target inside the Detector Solenoid. In order for the superconducting magnets to operate reliably and with a sufficient safety margin, the peak neutron flux entering the coils must be reduced by 3 orders of magnitude that is achieved by means of a sophisticated absorber placed in the magnet aperture. The proposed absorber, consisting of W- and Cu-based alloy parts, is optimized for the performance and cost. Results of MARS15 simulations of energy deposition and radiation are reported. The results of the PS magnet thermal analysis, coordinated with the coil cooling scheme, are reported as well for the selected absorber design.