Intrinsic noise sources in superconductors near the transition temperature

The performance of Transition Edge Sensors (TES) is limited by excess noise that is not predicted by the current theory of microcalorimeters and bolometers. The nature of this noise is currently unknown, but is likely to be dominated by fundamental physics of supeconductors. The University of Miami has recently started a joint effort between the microcalorimeter group and the superconductivity group to study and characterize the noise in TES. In particular, we plan to investigate the effect of flux motion due to self-field and external field and the effect of fluctuating order parameter by measuring the para-conductivity due to fluctuations in the number of Cooper pairs near the transition. We also plan to characterize the fundamental physical parameters of the TES to better predict their properties. In this paper we report our preliminary qualitative assessment of the problem, based on the literature, and we illustrate the experimental techniques that we plan to use for the investigation.