High-volume tunable resonator for axion searches above 7 GHz
Taj A. Dyson, Chelsea L. Bartram, Ashley Davidson, Jonah B. Ezekiel, Laura M. Futamura, Tongtian Liu, Chao-Lin Kuo
备注：
6 pages, 7 figures; references added, Table 2 updated, acknowledgments made more descriptive, grammar copy edits, and title updated to published version
We present results from the first experimental demonstration of a tunable thin-shell axion haloscope. This novel geometry decouples the overall volume of the cavity-based resonator from its resonant frequency, thereby evading the steep sensitivity degradation at high-frequencies. An aluminum $2.6$ L ($41$ $λ^3$) prototype which tunes from $7.1$ to $8.0$ GHz was fabricated and characterized at room temperature. An axion-sensitive, straightforwardly tunable $\mathrm{TM}$$_{010}$ mode is clearly identified with a room temperature quality factor, $Q$, of $\sim$$5,000$. The on-resonance $E$-field distribution is mapped and found to agree with numerical calculations. Anticipating future cryogenic operation, we develop an alignment protocol relying only on rf measurements of the cavity, maintaining a form factor of $0.57$ across the full tuning range. These measurements demonstrate the feasibility of cavity-based haloscopes with operating volume $V\ggλ^3$. We discuss plans for future development and the parameters required for a thin-shell haloscope exploring the post-inflationary axion parameter space ($\sim$$4$ to $\sim$$30$ GHz) at DFSZ sensitivity.
A tunable photonic band gap resonator for axion dark matter searches
Wellesley College（韦尔斯利学院）；University of California, Davis（加州大学戴维斯分校）；University of California, Berkeley（加州大学伯克利分校）；Brown University（布朗大学）；Yale University（耶鲁大学）；Los Alamos National Laboratory（洛斯阿拉莫斯国家实验室）
A new class of axion haloscope resonators: the polygonal coaxial cavity
INFN, Laboratori Nazionali di Legnaro（意大利国家核物理研究所，莱尼亚罗国家实验室）；Dipartimento di Fisica e Astronomia, Padova（帕多瓦大学物理与天文学系）；INFN, Sezione di Padova（意大利国家核物理研究所，帕多瓦分部）
