X-Ray Response of a Transition Edge Sensor Microcalorimeter With a Mushroom-Shaped Absorber

Superconducting transition edge sensor (TES) microcalorimeters are excellent energy-resolving devices for X-ray detection. We fabricated two types of TES microcalorimeter using different mushroom-shaped absorber thicknesses (0.5 and 5 mu m). Both types of TES microcalorimeter were irradiated with X-ray photons emitted by an Fe-55 source. X-ray detection signal pulses were collected to examine the effects of absorber thickness on performance. The values of the thermal conductance G were obtained by analyzing the current-voltage characteristics of the TES. By comparing the experimental G for both types of TES microcalorimeter, the absorber thickness was found to not affect the thermal properties of either type of TES microcalorimeter. The sensitivity alpha values for both TES microcalorimeters were obtained by analyzing the decay time constant of the X-ray detection signal pulses. The experimental ratio of the full-width at half-maximum value for the energy peaks of the Mn-K-alpha X-ray between both types of TES microcalorimeter was similar to theoretical estimations based on the different absorber thicknesses.