Modeling energy transport through the hot-electron microcalorimeter

We present numerical simulations of the diffusion of energy through the hot-electron microcalorimeter. This detector uses a normal-insulator-superconductor tunnel junction to measure the energy deposited by X-ray photons in the normal electrode. The photon energy is converted into heat stored by electrons and is detected as a change in the current flowing through the junction. We show that a measurement of only the pulse height can cause errors in the deduced photon energy, and that a numerical correction based on either the fall or rise time of the pulses can be used to deduce both the original photon energy and the location of the absorbed photon. (orig.)