Abstract: A thin-film superconductor device is disclosed which includes a superconductor film having one or more channels or regions of reduced width. The channel areas define predetermined volumes of superconductive material which is switched from its superconducting state to its normal state by impinging low energy particles. Return to the superconducting state is automatic after a fixed interval depending upon the volume of superconductive material in each channel region. The switching or state changing of the semiconductive region is independent of the energy of the triggering particles and results in output pulses of fixed height and width for a given channel volume. Applications of the disclosed superconductor device in digital memories and particle counting apparatuses are described.