Performance of hot-electron bolometers for infrared and x-ray detection

Hot-electron bolometers have wide applicability. Both IR bolometers as well as x-ray micro-calorimetric are currently being developed by the Space Research Organization Netherlands. The IR bolometers are equipped with space impedance matched spider web absorbers. The detectors have voltage biased superconducting transition edge thermometers. When operated in the negative feedback regime, their response time is appreciably reduced. As will be shown, electrical test give a wealth of information on the bolometer performance. In this paper typical bolometer parameters such as current-voltage characteristics, time constants and noise equivalent power are described. Electrical test results are presented. For an IR bolometer a loop gain of 500 combined with an electrical NEP of 2 by 10-17 W/(root)Hz has been realized.