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Description
Axion haloscopes are among the most promising approaches for detecting dark matter, requiring coverage over a broad frequency range from hundreds of MHz to hundreds of GHz. The detection principle proposed by Sikivie employs high-quality microwave resonators immersed in a strong magnetic field, with sensitivity significantly enhanced by cryogenic low-noise amplification.
The Dark Matter Axion Group (DMAG) at the Institute for Basic Science (IBS) operates several state-of-the-art haloscope experiments based on 8 T and 12 T superconducting magnets, including large-bore cavity systems. These experiments target the frequency range of 1–6 GHz using copper-based microwave cavities combined with high-temperature superconducting (HTS) structures.
The readout chain is based on Josephson parametric amplifiers (JPAs), achieving noise performance close to the standard quantum limit and enabling high scanning rates. A multi-JPA configuration extends the amplification bandwidth approximately linearly with the number of devices, without significant noise degradation.
We present the design and operational principles of the readout systems, along with recent developments in cavity technology leading to enhanced quality factors. Preliminary results from recent scans are discussed, and corresponding exclusion limits on the axion–photon coupling are reported.