PNNL

Abstract

We present an apparatus for detection of cyclotron radiation that allows a frequency-based ß± energy determination in the 5 keV to 5 MeV range, characteristic of nuclear ß decays. The cyclotron frequency of the radiating ß particles in a magnetic field is used to determine the ß energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of ß-s from 6He and ß+s from 19Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for ß spectroscopy over the full (MeV) energy range. This work is an important benchmark for the practical application of the CRES technique to a variety of nuclei, in particular, opening its reach to searches for evidence of new physics beyond the TeV scale via precision beta-decay measurements.