Response of niobium-based superconducting tunnel junctions in the soft-x-ray region 0.15–6.5 keV

Superconducting tunnel junctions as detectors for ultraviolet, optical, and near infrared astronomy

“…After removal of the contribution to the resolution from electronic noise a device-limited resolution dλ c was derived. Spatial variations in the response of the detector, similar to those reported by Verhoeve et al (1996) and Lumb et al (1995) at X-ray wavelengths, may account for the small degradation in resolution compared with that expected theoretically.…”

“…If each quasiparticle originally created in the film is transferred across the barrier on average of n times then, in the absence of loss processes, the average total electrical charge detected would be nQ i 0 . In this time-dependent process, recombination, diffusion losses and quasiparticle trapping will all reduce Q i 0 (t) (Booth 1987;Verhoeve et al 1996).…”

A superconducting tunnel junction x-ray detector with performance limited by statistical effects

“…Moreover, some parts of the Nb, such as the edges or the surfaces of the electrodes, may be of poor quality resulting in localized quasiparticle loss. 6 Once quasiparticles are trapped in the aluminum layers they are no longer influenced by these localized loss centers and the quasiparticle lifetime and the homogeneity of the detector response are enhanced. The increased quasiparticle lifetime and the increased tunnel rate both increase the total signal charge, thus improving the signal-to-noise ratio.…”

Energy resolution improvement of superconducting tunnel junction particle detectors with infrared-blocking filters

“…In an energy range below 3 keV, the response was almost linear, while a strong non-linearity was observed above 3 keV. The cause of the nonlinearity seems to be the self-recombination of quasi-particles confined to the small junction [15,16]. The energy resolution values are 138, 170, and 215 eV for 1.5, 2.0, and 3.0 keV Ar ions, respectively, after the non-linearity correction.…”