Sergey Uchaikin

Affiliation: IBS Center for Axion and Precision Physics Research

Research Interests: Superconductivity, Cryogenic Detectors, SQUID, Axion Search, Quantum Computer
Title: Quantum noise limited amplifier development for Axion Search Experiments at IBS/CAPP
Abstract: Axion search experiments aim to address fundamental questions in physics, including the strong CP problem and the nature of dark matter. The CAPP-MAX experiment at the Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) in South Korea is a leading effort in this field. This experiment features a 12-T Nb3Sn+NbTi superconducting magnet with a large bore (32 cm), a 37-liter cylindrical copper cavity, and a state-of-the-art microwave readout system utilizing a Josephson Parametric Amplifier (JPA) that approaches the quantum noise limit.

This presentation focuses on the development of a broadband readout system based on superconducting devices, specifically flux-driven Josephson Parametric Amplifiers. Our JPA demonstrates excellent noise performance near the quantum noise limit and has been successfully used in various CAPP experiments operating at 25-50 mK. To enhance the JPA’s bandwidth for wideband scanning experiments like axion searches, we employed techniques to expand its frequency coverage, reducing the need for frequent warm-up and amplifier replacement.

To achieve this, we explored innovative readout design approaches and implemented methods such as combinations of parallel, series, and series-parallel JPA connections. This allowed us to accommodate multiple JPAs within a single readout line. By utilizing multiple JPAs with different operating frequencies, we developed the Dulcimer Amplifier (DA), achieving a readout bandwidth of up to 300 MHz without compromising the JPA’s low noise characteristics. This presentation provides insights into the design considerations and testing methodologies employed for these multi-channel circuits. The outcomes presented here contribute to the advancement of broadband readout systems, offering potential applications in various fields requiring extended bandwidth capabilities.