Cryogenic amplifier for intermediate source impedance with gigahertz bandwidth

Abstract

We demonstrate a cryogenic amplifier for intermediate impedance sources, which operates from dc up to 1 GHz. The amplifier is based on rf operation of many parallelly coupled single-electron transistors (SETs). Unlike the ordinary radio-frequency single-electron transistor this amplifier operates without a tank circuit, impedance matching is achieved by coupling many SETs in parallel. The input impedance is purely capacitive, with a very small capacitance of 16 fF, and the frequency independent voltage noise is 10 nVHz. © 2006 American Institute of Physics.