Jitter and Readout Sampling Frequency Impact on the Athena/X-IFU Performance

The TES calorimeters like the one to be the core of the X-IFU instrument on board the Athena mission, provides unprecedented energy resolution. However, this resolution can be compromised due to the non-perfect sampling of the pulses risingedges (jitter) which could result in significant errors of the reconstructed energies if the standard optimal filtering algorithm is applied (with no further correction). If not corrected properly, these errors could induce a prohibitive broadening of the energy resolution. We present here the analysis of the magnitude of this effect and propose a correction. In addition, we evaluate the impact of a reduced readout sampling frequency in the energy resolution, once the jitter correction has been applied.