Development of radiation-resistant superconducting detector arrays for satellite missions in the millimetre waveband

Research Project

Project/Area Number	22K14060
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
Research Institution	Okayama University
Principal Investigator	Stever Samantha 岡山大学, 環境生命自然科学学域, 助教 (20842991)
Project Period (FY)	2022-04-01 – 2025-03-31
Project Status	Discontinued (Fiscal Year 2023)
Budget Amount *help	¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000) Fiscal Year 2026: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000) Fiscal Year 2025: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000) Fiscal Year 2024: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000) Fiscal Year 2023: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2022: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Keywords	phonon mitigation / microwave detector / resonator / MKID / superconductivity / radiation resistance / systematic effects / mm-wave
Outline of Research at the Start	We will carry out the work first produced by Karatsu et al. (2019) on the development of radiation-resistant MKID arrays. Building upon previous work, we will develop and test multiple low-Tc materials and designs in order to optimise effectiveness and reduce array dead time to <1% that of an unmitigated array, with multiple device types tested. We will optimise the design based on these results and subsequent modelling. By the end of this project we aim to achieve a large array (10,000 detectors) for such a targeted study.
Outline of Annual Research Achievements	During the research period so far, we have collaborated with AIST (Tsukuba) to fabricate several microwave resonator designs with varying low T_c films for phonon absorption. We have characterised these detectors at Okayama University, and also at Paris-Saclay university for an aluminium-backed detector requiring subkelvin cryogenics. We have produced a microwave circuit at room temperature which allows us to measure two detectors in the time domain simultaneously. We are in the process of using this circuit to measure the co-incidence from laser pulses or radiation, in order to verify the phonon absorption of the thin film.
Current Status of Research Progress	Current Status of Research Progress 2: Research has progressed on the whole more than it was originally planned. Reason It is progressing smoothly.
Strategy for Future Research Activity	We plan to produce another aluminium thin film backed device because the current one has an electrical short. Following that, we will characterise its frequency response before irradiating it again in a dilution fridge at KEK (Tsukuba).