Bolometers as spectrometers for X-ray astronomy

We have investigated the possiblity to use composite diamond-germanium bolometers, originally developed for I.R. astronomy, for the individual detection of X-ray photons. The advantage of a composite bolometer is that it separates the absorption and detection functions. Diamond, as absorber, is especially interesting because of its high-thermal diffusivity and low heat capacity. Associated with a 103 cm2 telescope such a device, whose performance is essentially signal limited, is able to detect, an emission line of 10-7 ph.cm-2s-1 in 105 seconds in the spectrum of a faint X-ray source