Relativistic Cyclotron Radiation Detection of Tritium Decay Electrons as a New Technique for Measuring the Neutrino Mass

TL;DR

This paper proposes a novel technique using relativistic cyclotron radiation detection to measure the energy of electrons from tritium decay, aiming to improve neutrino mass measurements beyond current limits.

Contribution

It introduces a new electron spectroscopy method based on detecting emitted cyclotron radiation, enhancing precision in neutrino mass experiments.

Findings

Calculations show potential for high energy resolution.

Analysis indicates feasible high-rate measurements.

Systematic error estimates support method viability.

Abstract

The shape of the beta decay energy distribution is sensitive to the mass of the electron neutrino. Attempts to measure the endpoint shape of tritium decay have so far seen no distortion from the zero-mass form, thus placing an upper limit of m_nu_beta < 2.3 eV. Here we show that a new type of electron energy spectroscopy could improve future measurements of this spectrum and therefore of the neutrino mass. We propose to detect the coherent cyclotron radiation emitted by an energetic electron in a magnetic field. For mildly relativistic electrons, like those in tritium decay, the relativistic shift of the cyclotron frequency allows us to extract the electron energy from the emitted radiation. We present calculations for the energy resolution, noise limits, high-rate measurement capability, and systematic errors expected in such an experiment.