X-Ray Spectroscopy (XRS)
X-ray spectroscopy is used to analyze the content of interstellar objects. Using spectroscopy, scientists can determine the elemental composition of an interstellar body while acquiring its image.
In particular, some x-ray spectroscopy involves using microcalorimeters
to measure counts of x-ray photons coming from an object. The microcalorimeter
has an absorbing material with a temperature sensor that connects through
a weak link to a heat sink. When an x-ray photon hits the absorber the
temperature changes by a very small increment. The excess heat feeds through
the weak link to the heat sink and the system returns to its original
temperature. In order to detect these small temperature changes, the original
temperature of the absorber must remain at a constant cryogenic temperature
(50-100mK). This is where the adiabatic demagnetization refrigerator comes
in; it keeps the system at such a low temperature.