Pulses Induced in Tunneling Currents Between Superconductors by Alpha-Particle Bombardment

Abstract

A superconducting tunnel junction was bombarded with alpha particles and the resulting pulses in the quasiparticle tunneling current were observed. The possibility of utilizing this effect in nuclear spectrometry is discussed.

Superconducting detectors and mixers for millimeter and submillimeter astrophysics

“…In a rough sense, the tunnel junctions are used to filter out the Cooper pairs but let the quasi-particles pass. Single energetic particles or photons may break a large number of Cooper pairs into quasi-particles, thereby producing a current pulse flowing through the tunnel junction, whose amplitude indicates the energy of the event [125]- [136]. Alternatively, a steady flux of submillimeter photons absorbed in the superconductor will produce a dc current in the junction.…”

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

“…As identified by Perryman, et al (1993) optical detectors based on superconducting materials offer two important advantages over those based on semiconductors: (a) according to the BCS theory of superconductivity the energy gap ∆ between the ground state, as represented by the bound Cooper pairs, and the first excited state, containing the broken Cooper pairs known as "quasiparticles", is generally more than 10 3 times smaller than the energy gap between the valence and conduction bands of a semiconductor (Bardeen et al 1957); (b) the Debye energy Ω D is much larger than the superconducting energy gap, thereby allowing phonons created as a result of the photoabsorption process to break Cooper pairs and create free charge (Wood & White 1969). For example in bulk Al ∆ ∼ 170 µ eV while Ω D is as large as ∼ 37 MeV.…”

Observation of nuclear gamma resonance with superconducting tunnel junction detectors

“…2 The application of STJs for radiation detection started from the registration of tunneling current pulses from Sn STJ bombarded by alpha particles. 3 The theory and applications of STJ detectors for photon detection have been considered by Friedrich. 4 The development of STJ detectors along with other types of LTDs gave an impulse to the development of nonequilibrium superconductivity and issues concerning the relaxation of excitations in superconducting materials used for the detector design.…”