Axion haloscope using an 18 T high temperature superconducting magnet

Abstract

We report details on the axion dark matter search experiment that uses the new technologies of a high-temperature superconducting (HTS) magnet and a Josephson parametric converter (JPC). An 18 T HTS solenoid magnet is developed for this experiment. The JPC is used as the first stage amplifier to achieve a near quantum-limited low-noise condition. A first dark-matter axion search was performed with the 18 T axion haloscope [Youngjae Lee, Phys. Rev. Lett. 128, 241805 (2022)PRLTAO0031-900710.1103/PhysRevLett.128.241805]. The scan frequency range is from 4.7789 GHz to 4.8094 GHz (30.5 MHz range). No significant signal consistent with Galactic dark matter axion is observed. Our results set the best limit of the axion-photon-photon coupling (gaγγ) in the axion mass range of 19.764-19.890 μeV. Using the Bayesian method, the upper bounds of gaγγ are set at 0.98×|gaγγKSVZ| (1.11×|gaγγKSVZ|) in the mass ranges of 19.764-19.771 μeV (19.863 to 19.890 μeV), and at 1.76×|gaγγKSVZ| in the mass ranges of 19.772-19.863 μeV with 90% confidence level, respectively. We report design, construction, operation, and data analysis of the 18 T axion haloscope experiment. © 2022 authors. Published by the American Physical Society.