Jul 4 – 11, 2018
Asia/Seoul timezone

Wideband SQUID Amplifiers for Axion Search Experiments

Jul 6, 2018, 6:30 PM


Poster Dark Matter Detection POSTER


Dr Andrei Matlashov (Center for Axion and Precision Physics Research, IBS)


It was theoretically shown that axions can be detected by converting them to microwave photons inside high-Q cavity resonators in the presence of a strong magnetic field [1]. In such experiments, very weak microwave signals should be scanned in a wide frequency range. The best semiconductor amplifiers have a lowest noise temperature plateau of about 1.1 K even at significantly lower ambient temperature. Superconducting quantum interference devices, or SQUIDs, can work as microwave amplifiers with noise temperature close to the standard quantum limit (SQL), TSQL = hf/kB ≈ 50 mK at 1 GHz [2]. Previously designed SQUID-based high-frequency amplifiers have narrow bandwidth due to a microstrip resonant input coil [3]. It requires serial replacements of SQUID preamplifiers in order to scan a wide frequency range. This procedure is complex and time consuming because of a large mass of hardware should be cooled down below 100 mK. SQUID-based microwave amplifiers with a suitable amplification should be designed with the smallest possible tunnel junction capacitance, with reasonably low SQUID loop inductance, and maximal transfer function at the working point. Sub-micron size Josephson junctions with a very small capacitance 0.04 pF were used for low-frequency SQUID current sensors [4]. We tested a few of such sensors at high frequencies and found out that they can work as both resonant and wideband microwave amplifiers. In this presentation, we report on SQUID-based wideband microwave amplifiers fabricated using sub-micron size Josephson junctions with very low capacitance. A single amplifier can be used for axion search experiments in a frequency range from about 500 MHz to approximately 5 GHz.

Primary author

Dr Andrei Matlashov (Center for Axion and Precision Physics Research, IBS)


Mr Doyu Lee (Center for Axion and Precision Physics Research, IBS) Dr Woohyun Chung (Center for Axion and Precision Physics Research, IBS) Ms Seon Jung Oh (Center for Axion and Precision Physics Research, IBS) Dr Matthias Schmelz (Leibniz Institute of Photonic Technology) Dr Vyacheslav Zakosarenko (Leibniz Institute of Photonic Technology) Dr Ronny Stolz (Leibniz Institute of Photonic Technology)

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