Electron-phonon multiplier involving a cascade of NIS tunnel junctions and hot-electron microcalorimeters

A device for amplifying weak electric signals arising in a normal-or a superconducting-metal absorber upon the absorption of photons or phonons is proposed. The device consists of a cascade of normal-metal-insulator-superconductor (NIS) tunnel junctions, where the normal metal is used as an electrode and as a hot-electron microcalorimeter. Tunneling through the barrier, a particle transports energy of about Δ (energy gap in the superconductor) from one microcalorimeter to another and amplifies the current through the next NIS junction. The device operates as a solid-state electron multiplier at low temperatures.