Speaker
Description
This work was performed as part of the international Project 8 collaboration. The goal of the Project 8 experiment is to measure the absolute neutrino mass using tritium beta decays, which involves precisely measuring the energies of the beta-decay electrons in the high-energy tail of the spectrum.
The experimental installation of the Project 8 Atomic Tritium Demonstrator requires a magnet with rather unusual field properties. The magnet has to contain within the cold mass a large closed volume surrounded by a continuous, uninterrupted boundary with high field, exceeding 2 T, whereas the field in a substantial volume inside this boundary has to be of the order of $10^{-4}$ T or less. A 1 T solenoid field provides the background field necessary for the detection of beta-decay electrons.
A proposed toroidal magnet system (Ioffe-Pritchard trap) comprised of specially shaped multiple racetrack windings satisfies these unusual requirements. The magnet is made of NbTi wire and expected to be conduction cooled. Manufacturability issues are addressed as well as the effect of the tolerances on the field quality. Additional topological features providing a low-field duct for interfacing with the peripheral coils of the energy selector are included in the design.
