Tunable Rectangular Resonant Cavities for Axion Haloscopes

TL;DR

This paper explores a tunable rectangular resonant cavity design for axion haloscopes, demonstrating its advantages over traditional cylindrical cavities, especially at higher frequencies, to improve dark matter detection sensitivity.

Contribution

It introduces a simple, tunable rectangular cavity design and compares its performance to standard cylindrical cavities, highlighting potential benefits for axion searches.

Findings

Rectangular cavities support similar modes to cylindrical ones.

They offer advantages in sensitivity and practicality at higher frequencies.

The design is suitable for advancing axion dark matter detection.

Abstract

Axions are a compelling dark matter candidate, and one of the primary techniques employed to search for them is the axion haloscope, in which a resonant cavity is deployed inside a strong magnetic field so that some of the surrounding axions may convert into photons via the inverse Primakoff effect and become trapped inside the resonator. Resonant cavity design is critical to the sensitivity of a haloscope, and several geometries have been utilised and proposed. Here we consider a relatively simple concept - a rectangular resonant cavity with a tunable wall - and compare it to the standard tuning rod-type resonators employed in the field. We find that the rectangular cavities support similar modes to cylindrical tuning rod cavities, and have some advantages in terms of axion sensitivity and practicality, particularly when moving to higher frequencies which are of great and growing interest in the international axion dark matter community.