Output signal from Nb-based tunnel junctions by irradiation of 6 keV X-rays

Ishibashi, Kenji; Mori, Kenichi; Takeno, Kazuhiko; Nagae, Toshimitsu; Matsumoto, Yasuhiko; Takada, Susumu; Nakagawa, Hiroshi; Akoh, H.

doi:10.1109/20.133759

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…22,26,27 For detection of high energy photons hν Φ ≫ 2∆, η ≃ 0.59. [19][20][21] . If we assume that P det is small compared to P abs so that δN qp /N qp is small (as it must be for a linear detector) then the relevant N qp and τ r are as already calculated.…”

Section: Solutions For Non-equilibrium Resonatorsmentioning

confidence: 99%

“…The kinetic equations have been used to investigate the non-linear effect of high energy photon interactions at low temperatures. [19][20][21] To our knowledge no full non-linear calculations exist of the effect of microwave drive at low temperatures on SRs.…”

Section: Introductionmentioning

confidence: 99%

“…Crucially however in that work solutions were obtained close to T c where microwave drive can lead to gap-enhancement effects. The same kinetic equations have also been used to investigate the non-linear effect of high-energy photon interactions at T/T c ∼ 0.1 [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

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Non-equilibrium superconductivity in quantum-sensing superconducting resonators

Goldie

Withington

2012

Supercond. Sci. Technol.

130

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We have calculated the non-equilibrium quasiparticle and phonon distributions f (E), n(Ω), where E and Ω are the quasiparticle and phonon energies respectively, generated by the photons of the probe signal of a low temperature superconducting resonator SR operating well-below its transition temperature Tc as the absorbed probe power per unit volume P abs was changed. The calculations give insight into a rate equation estimate which suggests that the quasiparticle distributions can be driven far from the thermal equilibrium value for typical readout powers. From f (E) the driven quasiparticle number density Nqp and lifetime τr were calculated. Using Nqp we defined an effective temperature T * N to describe the driven f (E). The lifetime was compared to the distribution averaged thermal lifetime at T * N and good agreement was found typically within a few percent. We used f (E) to model a representative SR. The complex conductivity and hence the frequency dependence of the experimentally measured forward scattering parameter S21 of the SR as a function of P abs were found. The non-equilibrium S21 cannot be accurately modeled by a thermal distribution at an elevated temperature T * 21 having a higher quality-factor in all cases studied and for low P abs T * 21 ∼ T * N . Using τr and Nqp we determined the achievable Noise Equivalent Power of the resonator used as a detector as a function of P abs . Simpler expressions for T * N as a function of P abs were derived which give a very good account of T * N and also Nqp and τr. We conclude that multiple photon absorption from the probe increases the quasiparticle number above the thermal background and ultimately limits the achievable NEP of the resonator.

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Section: Solutions For Non-equilibrium Resonatorsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Non-equilibrium superconductivity in quantum-sensing superconducting resonators

Goldie

Withington

2012

Supercond. Sci. Technol.

130

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“…(10) When signal charges Q1 (i = 1, 2, , n) are simultaneously induced from the STJs, as seen in Fig. 5, V is given by Vs(Ql+Q2++QnnQ')/C (11) =Q'/C'. Fig.…”

Section: Effective Capacitance Ceffmentioning

confidence: 99%

<title>X-ray detection with an Nb-based junction and investigation of series-junction detectors</title>

et al. 1992

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Two topics on our recent investigations into superconducting tunnel junction (STJ) detectors are discussed: the single Nb/A1.AlOx/Al/Nb junction for high-resolution x-ray detection and the series-connected superconducting tunnel junction detectors (SCSDs) with high detection efficiency. Using a single Nb/AlAlOx/Al/Nb junction with rather large area of 178 x 178 2, we obtained a high energy resolution of 88 eV for 5.9-keY x-rays. The signal-to-noise ratio of the SCSD is discussed from a simple theoretical formulation of electronics, showing that the series-connected STJs can developed as a nuclear radiation detector both with high energy resolution and high efficiency. Recent experimental results of our SCSD are also given in this paper.

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“…[1], [13] The coupled kinetic equations have been used to investigate the effect of high energy photon interactions (hν sig /∆ ∼ 3 × 10 7 ) at T /T c ∼ 0.1. [14], [15] In Ref. [1] full non-linear solutions were obtained which is the approach we have adopted.…”

Section: Introductionmentioning

confidence: 99%

Non-Equilibrium Superconductivity in Kinetic Inductance Detectors for THz Photon Sensing

Goldie¹,

Withington²

2014

Preprint

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Low temperature Kinetic Inductance Detectors (KIDs) are attractive candidates for producing quantumsensitive, arrayable sensors for astrophysical and other precision measurement applications. The readout uses a low frequency probe signal with quanta of energy well-below the threshold for pair-breaking in the superconductor. We have calculated the detailed non-equilibrium quasiparticle and phonon energy spectra generated by the probe signal of the KID when operating well-below its superconducting transition temperature Tc within the framework of the coupled kinetic equations described by Chang and Scalapino.[1] At the lowest bath temperature studied T b /Tc = 0.1 the quasiparticle distributions can be driven far from equilibrium. In addition to the low frequency probe signal we have incorporated a high frequency (∼ 1 THz) source signal well-above the pair-breaking threshold of the superconductor. Calculations of source signal detection efficiency are discussed.

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Output signal from Nb-based tunnel junctions by irradiation of 6 keV X-rays

Cited by 8 publications

References 10 publications

Non-equilibrium superconductivity in quantum-sensing superconducting resonators

Non-equilibrium superconductivity in quantum-sensing superconducting resonators

<title>X-ray detection with an Nb-based junction and investigation of series-junction detectors</title>

Non-Equilibrium Superconductivity in Kinetic Inductance Detectors for THz Photon Sensing

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