Noise in Metal Bolometers

The impedances and the noise generated in the Narda model N821B metal bolometers with direct current passing through them are measured over the frequency range of 1 to 100 kc/sec. The impedance measurements indicate that the impedance of the bolometer consists of resistive part and capacitive-reactance part. This agrees with IΔV effect discussed by Becking and van Vliet. The noise measurements indicate that large amounts of noise over Johnson noise are associated with the temperature-fluctuation noise and 1/f noise in the bolometer when direct current is passed through it. For a bias current lower than 6 mA, the temperature-fluctuation noise predominates and the observed noise has spectral distribution in agreement with the theoretical results obtained by Milatz and van der Velden. For a higher current (8.7 mA), the observed noise shows 1/f characteristics.