A superconducting radiation detector relies upon the abruptness of a superconducting
transition edge to converts a slight heat generated by an X-ray into a high signal
current and uses an electrothermal self-feedback mechanism to provide a high energy
resolution and a high counting rate. A calorimeter incorporating such a radiation
detector has an absorber for absorbing X-rays, a resistor formed of a superconductor
provided under the absorber and having a resistance value that varies with heat
generated in the absorber, superconducting wires for connecting the resistor to
an external current detector, a membrane on which the resistor is provided, and
an insulating film provided between the resistor and the absorber and having at
least one hole penetrating therethrough, the resistor and the absorber being in
contact through the hole.
