Large-Volume Centimeter-Wave Cavities for Axion Searches

TL;DR

This paper introduces a new class of large-volume, thin-shell cavities for axion dark matter searches, significantly increasing active volume while maintaining quality factor and tuning range, optimized for centimeter wavelengths.

Contribution

Proposes a novel thin-shell cavity design with over 20 times larger volume for axion detection, using numerical analysis and standard machining techniques for high-frequency applications.

Findings

Cavities have over 20X larger volume than conventional designs.

TM_010 modes are singly polarized and suitable for axion-photon conversion.

Design is feasible with standard machining for 10-100 GHz frequencies.

Abstract

The scan rate of an axion haloscope is proportional to the square of the cavity volume. In this paper, a new class of thin-shell cavities are proposed to search for axionic dark matter. These cavities feature active volume much larger (>20X) than that of a conventional cylindrical haloscope, comparable quality factor Q, and a similar frequency tuning range. Full 3D numerical finite-element analyses have been used to show that the TM_010 eigenmodes are singly polarized throughout the volume of the cavity and can facilitate axion-photon conversion in uniform magnetic field produced by a superconducting solenoid. To mitigate spurious mode crowding and volume loss due to localization, a pre-amplification binary summing network will be used for coupling. Because of the favorable frequency-scaling, the new cavities are most suitable for centimeter-wavelength (~ 10-100 GHz), corresponding to the promising post-inflation axion production window. In this frequency range, the tight machining tolerances required for high-Q thin-shell cavities are achievable with standard machining techniques for near-infrared mirrors.