• 제목/요약/키워드: SQUID current amplifier

검색결과 4건 처리시간 0.016초

X-선 미소열량계 신호 검출을 위한 광대역 SQUID 전류증폭기와 조절 회로 (Wide-bandwidth SQUID Current Amplifier and Control Electronics for X-ray Microcalorimeter)

  • 김진목;이용호;권혁찬;김기웅;박용기
    • Progress in Superconductivity
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    • 제5권1호
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    • pp.31-37
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    • 2003
  • Wide-bandwidth SQUID current amplifier and its control electronics have been constructed for detecting pulse outputs of a superconducting microcalorimeter. The current amplifier made of a double relaxation oscillation SQUID (DROS) has a bandwidth of 1.2 MHz and typical white noise level of about 6 pA/(equation omitted) Hz. To increase the dynamic range of the current amplifier, the flux-locked loop (FLL) has additional circuits to reset the integrator and to count reset numbers which present the number of passed flux quanta. In this system, dynamic range covers from -65 mA to +65 mA. SQUID electronics are controlled by software to get the optimum FLL condition, and to control the current to bias the transition edge sensor (TES). The electronics are shielded from the outside electromagnetic noises by using an aluminum case of 66 mm ${\times}$ 25 mm ${\times}$ 100 mm, and consist of 2 separate printed-circuit-boards for the current amplifier and the control electronics, respectively. The SQUID current amplifier and its control electronics will be used in TESs for detecting photons such as UV and X-ray with high energy resolution.

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Gain characteristics of SQUID-based RF amplifiers depending on device parameters

  • Lee, Y.H.;Yu, K.K.;Kim, J.M.;Lee, S.K.;Chong, Y.;Oh, S.J.;Semertzidis, Y.K.
    • 한국초전도ㆍ저온공학회논문지
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    • 제21권1호
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    • pp.10-14
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    • 2019
  • Radio-frequency (RF) amplifiers based on direct current (DC) superconducting quantum interference device (SQUID) have low-noise performance for precision physics experiments. Gain curves of SQUID RF amplifiers depend on several parameters of the SQUID and operation conditions. We are developing SQUID RF amplifiers for application to measure very weak RF signals from ultra-low-temperature high-magnetic-field microwave cavity in axion search experiments. In this study, we designed, fabricated and characterized SQUID RF amplifiers with different SQUID parameters, such as number of input coil turn, shunt resistance value of the junction and coupling capacitance in the input coil, and compared the results.

Correction of resonance frequency for RF amplifiers based on superconducting quantum interference device

  • Lee, Y.H.;Yu, K.K.;Kim, J.M.;Lee, S.K.;Chong, Y.;Oh, S.J.;Semertzidis, Y.K.
    • 한국초전도ㆍ저온공학회논문지
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    • 제20권4호
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    • pp.6-10
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    • 2018
  • Low-noise amplifiers in the radio-frequency (RF) band based on the direct current (DC) superconducting quantum interference device (SQUID) can be used for quantum-limited measurements in precision physics experiments. For the prediction of peak-gain frequency of these amplifiers, we need a reliable design formula for the resonance frequency of the microstrip circuit. We improved the formula for the resonance frequency, determined by parameters of the DC SQUID and the input coil, and compared the design values with experimental values. The proposed formula showed much accurate results than the conventional formula. Minor deviation of the experimental results from the theory can be corrected by using the measured geometrical parameters of the input coil line.