Simulations of Resonant Cavities Used In Axion Detection

The Axion Dark Matter eXperiment(ADMX) uses high quality factor (Q) resonant RF cavities as the primary detection element of the axion-haloscope. In doing so, ADMX has been able to rule out axions with DFSZ coupling generating frequencies f = m_ac²/h in the 600 MHz to 1 GHz range. Efforts to extend this space in the future will require new cavity designs that can be tuned through the desired frequencies, while also optimizing the resonant properties sought-after in haloscope searches. These properties include f, Q, and the axion-specific quantity known as the form factor C. This talk will discuss the results from simulations performed of various cylindrical cavity designs. The cavities considered here seek to be tunable within the 1--2 GHz range. This study focuses on the performance of the TM₀₁₀ resonant mode, as its field shape tends to produce the highest C values. In addition to room temperature (300 K) measurements, simulations are also performed with low temperature (4 K) consideration, where Q values increase dramatically. Methods to reduce leakage of the resonant energy from the cavity are addressed. The results of these tests are an attempt to identify characteristics for an optimized resonator configuration that could be constructed for use in the ADMX experiment.