Solenoid Magnet System for the Fermilab Mu2e Experiment

Abstract

The Fermilab Mu2e experiment seeks to measure the rare process of direct muon to electron conversion in the field of a nucleus. Key to the design of the experiment is a system of three superconducting solenoids; a muon production solenoid (PS) which is a 1.8 m aperture axially graded solenoid with a peak field of 5 T used to focus secondary pions and muons from a production target located in the solenoid aperture; an "S shaped" transport solenoid (TS) which selects and transports the subsequent muons towards a stopping target; a detector solenoid (DS) which is an axially graded solenoid at the upstream end to focus transported muons to a stopping target, and a spectrometer solenoid at the downstream end to accurately measure the momentum of the outgoing conversion electrons. The magnetic field requirements, the significant magnetic coupling between the solenoids, the curved muon transport geometry and the large beam induced energy deposition into the superconducting coils pose significant challenges to the magnetic, mechanical, and thermal design of this system. In this paper a conceptual design for the magnetic system which meets the Mu2e experiment requirements is presented.

Quench protection analysis of the Mu2e production solenoid

“…The Mu2e magnet system consists of three large superconducting solenoids [1]. The first in the chain of magnets is the Production Solenoid (PS) [2], shown in Fig.…”

Reference Design of the Mu2e Detector Solenoid

“…1) [2] consists of three large superconducting solenoids: Production Solenoid, Transport Solenoid and Detector Solenoid. The last in the chain of magnets, the Detector Solenoid (DS) [3], houses the muon stopping target and the detectors.…”

Conceptual Design of the Mu2e Production Solenoid

“…he Mu2e magnet system consists of three large superconducting solenoids [1]. The first in the chain of magnets is the Production Solenoid (PS) whose role is to collect and focus pions and muons generated in interactions of an 8-GeV proton beam with a tilted high-Z target, by supplying a peak axial field between 4.6 T and 5.0 T and an axial field gradient of about 1 T/m within a 1.5 m warm bore.…”

“…The detailed description of the PS conceptual design is reported elsewhere [1], [4]. This paper focuses on the selected parameters of the cable and insulation and recent updates to the electromagnetic, structural and cryostat support designs.…”