Development of polycapillary optics for a TES microcalorimeter EDS system on a scanning transmission electron microscope

Abstract

An energy dispersive spectrometer with a superconducting transition edge sensor (TES) microcalorimeter mounted on a scanning transmission electron microscope (STEM) has been developed to improve the accuracy of nanoscale material analysis. Because of the magnetic field generated by the STEM objective lens, a TES microcalorimeter cannot be placed in a STEM column. Therefore, a polycapillary optics is used for collecting X-rays emitted by a STEM specimen on the TES microcalorimeter. The counting rate of 300 cps was insufficient for a practical application to the STEM. To achieve the counting rate larger than 5000 cps, we are now conducting development of a 64-pixel TES microcalorimeter system operating on the STEM. We developed a new polycapillary optics for a 64-pixel TES microcalorimeter with using a X-ray transmission simulation model that we made. We performed energy spectrum measurements of X-rays transmitted by the fabricated new polycapillary optics for evaluating the X-ray transmission characteristics.