Investigation of a nonequilibrium electron subsystem in low-temperature microwave detectors

The electron energy distributions arising in small-size metal absorbers of microwave radiation detectors operating at ultralow temperatures have been calculated using the kinetic equation. It is shown that the electron distributions are nonequilibrium, significantly different from the Fermi distribution, and are determined by the ratio of the rates of electron-electron and electron-phonon relaxation and by the effect of the measuring element (superconductor – insulator – normal metal junction) on the absorber. The response of such a bolometer is calculated and compared to the experimental data.