Microwave radiation detector

A detector arrangement for detecting microwave radiation, comprising:

• at least one detector;
• and
• a resonance measurement circuit configured to measure the resonance frequency of a tank circuit coupled to said detector output,
• wherein:
• the detector is a detector of microwave radiation,
• the detector comprises a signal input, a detector output, an absorber element of ohmic conductivity coupled to said signal input through a first length of superconductor, and a variable impedance element the impedance of which is configured to change as a function of temperature,
• the variable impedance element is coupled to said detector output through a second length of superconductor,
• the detector comprises a heating input,
• the detector comprises a heating element coupled to said heating input through a third length of superconductor, and
• said absorber element, said variable impedance element, and said heating element are coupled to each other through superconductor sections of lengths shorter than any of said first, second, and third lengths of superconductor to allow hot electron diffusion between said absorber element, said variable impedance element, and said heating element while blocking quasiparticle thermal transport of heat through said first, second, and third lengths of superconductor.