Abstract: A superconducting transition-edge sensor with an electrothermal-feedback circuit, a heat sink thermally coupled thereto, a bias-feedback circuit electrically coupled with the electrothermal feedback circuit, and a current sensor electrically coupled with the bias-feedback circuit and inductively coupled with the electrothermal-feedback circuit.

Abstract: A novel type of superconducting transition edge sensor is described. The sensor comprises a primary heat sink maintained at a constant temperature and a resistive means, such as a superconducting film, in thermal contact with the primary heat sink. The temperature of the primary heat sink is kept well below the transition temperature of the superconducting film. The film is voltage biased, so that its temperature is maintained within its superconducting transition through electrothermal feedback: at equilibrium, the Joule heating of the film is equal to the heat loss from the film to the substrate. The energy deposited in the film by a particle incident on the sensor is measured by the reduction in Joule heating.