A High-frequency Resonant Cavity for the Project 8 Experiment*

Project 8 aims to use the novel technique of cyclotron radiation emission spectroscopy (CRES) to measure the atomic tritium beta-decay spectrum endpoint and probe the absolute neutrino mass scale down to 40meV. CRES uses an external magnetic field to induce cyclotron motion of beta decay electrons in order to measure the cyclotron frequency, which is inversely related to the electron energy, thereby allowing the reconstruction of the beta decay spectrum. Project 8’s Phases I and II used a waveguide to demonstrate measurement of cyclotron radiation from a single electron and the first neutrino mass limit using CRES, respectively. Before the final measurement in Phase IV, Phase III will perform large volume CRES to surpass statistics limitations seen in Phase II. Extensive R&D indicates that a microwave resonant cavity is best suited for scaling up CRES. This talk will motivate and discuss the implementation of a high-frequency cavity that will be used in a proof-of-concept experiment, the Cavity CRES Apparatus (CCA), currently being commissioned at the University of Washington in Seattle.