Implementation and Optimization of the PTOLEMY Transverse Drift Electromagnetic Filter

Abstract

The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium beta-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-well design to simultaneously drain the parallel and transverse kinetic energies throughout the length of the filter. These optimizations are shown, in simulation, to achieve low-energy electron transport from a 1 T iron core (or 3 T superconducting) starting field with initial kinetic energy of 18.6 keV drained to <10 eV (<1 eV) in about 80 cm. This result for low field operation paves the way for the first demonstrator of the PTOLEMY spectrometer for measurement of electrons near the tritium endpoint to be constructed at the Gran Sasso National Laboratary (LNGS) in Italy.

29 pages, 25 figures

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Cited by in corpus (9)

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• Limits on the cosmic neutrino background
• Searches for massive neutrinos with mechanical quantum sensors
• Detection of Low-Energy Electrons with Transition-Edge Sensors
• Stability of Highly Hydrogenated Monolayer Graphene in Ultra-High Vacuum and in Air
• Probing sterile neutrino dark matter in the PTOLEMY-like experiment
• A study of the relativistic corrections to polarized tritium $\beta$-decay
• The $\beta$-decay spectrum of Tritiated graphene: combining nuclear quantum mechanics with Density Functional Theory
• Cosmic neutrino background detection in the minimally extended Standard Model