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 5μm). Both types of TES microcalorimeter were irradiated with X-ray photons emitted by an ⁵⁵Fe 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 α 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_α X-ray between both types of TES microcalorimeter was similar to theoretical estimations based on the different absorber thicknesses.