Noise of a bolometer with vanishing self-heating

Abstract We discuss the thermal noise of a low temperature magnetic bolometer, which has the property of not being heated by the thermometer measurement power. This bolometer is promising for measuring small energy pulses from absorbed single particles or X-rays. Having thermal noise only we can calculate the uncertainty of energy detection and we show that this is not limited by the quantity 4kT 2 C . This result is of interest with respect to experiments which demand large absorbers.