Evaluation of current sensitivity of quantum flux parametron. (4th July 2017)

• Record Type: Journal Article
• Authors: Yamanashi, Yuki; Matsushima, Takashi; Takeuchi, Naoki; Yoshikawa, Nobuyuki; Ortlepp, Thomas
• Is Part Of: Superconductor science & technology. Volume 30:Number 8(2017:Aug.)
• Publication Date: 2017-07-04
• Subjects: QFP -- comparator -- gray zone -- sensor array -- read-out circuit; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/aa73be
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: Current sensitivity of a quantum flux parametron (QFP) was evaluated by measuring gray zone width on the basis of both circuit simulation and measurements, for superconducting sensing systems composed of a superconducting sensor array and superconducting read-out and signal processing circuits. Simulation results indicate a narrow gray zone width can be obtained by decreasing inductances comprising the QFP. Moreover, both high-sensitivity and low-power operation of the QFP can be realized by using optimized circuit parameters with an excitation current that has long rise time. A gray zone width of approximately 0.5 μ A, which is smaller than that of the Josephson current comparator based on a single flux quantum circuit, was obtained experimentally, using a trapezoidal excitation current with rise time of 50 μ s. These results indicate the QFP is promising for the read-out circuit in superconducting sensing systems, due to its high sensitivity and low power consumption.