A superconducting thin-film low-energy particle detector

Techniques for constructing a superconducting thin-film particle detector have been developed. Detecting surfaces were fabricated by evaporating a 500 Å tinindium film on a glass cover slide and scratching to obtain a 1 micron strip. At a point just below the Tcand at current densities near Ic, pulses due to single incident Ar, Ar+, He, and He+ particles were observed. Pulses were observed for helium and argon down to 200 eV and 150 eV respectively and up to approximately 800 eV. The response of the detector to ions and neutral particles was identical with near 100% efficiency. Calculated values for the size of normal regions of the film due to incident particles were of the same order of magnitude as those measured. Pulse height analysis indicated no dependence on incident particle energy. It was concluded that this lack of pulse height dependence on incident energy was due to an intrinsic fluctuation phenomenon of the superconducting film.