Microcalorimeter-type energy dispersive X-ray spectrometer for a transmission electron microscope

Abstract

A new energy dispersive X-ray spectrometer (EDS) with a microcalorimeter detector equipped with a transmission electron microscope (TEM) has been developed for high- accuracy compositional analysis in the nanoscale. A superconducting transition-edge-sensor-type microcalorimeter is applied as the detector. A cryogen-free cooling system, which consists of a mechanical and a dilution refrigerator, is selected to achieve long-term temperature stability. In order to mount these detector and refrigerators on a TEM, the cooling system is specially designed such that these two refrigerators are separated. Also, the detector position and arrangement are carefully designed to avoid adverse affects between the superconductor detector and the TEM lens system. Using the developed EDS system, at present, an energy resolution of 21.92 eV full-width-at-half maximum has been achieved at the Cr K alpha line. This value is about seven times better than that of the current typical commercial Si(Li) detector, which is usually around 140 eV. The developed microcalorimeter EDS system can measure a wide energy range, 1-20 keV, at one time with this high energy resolution that can resolve peaks from most of the elements. Although several further developments will be needed to enable practical use, highly accurate compositional analysis with high energy resolution will be realized by this microcalorimeter EDS system.

A Transition Edge Sensor Microcalorimeter System for the Energy Dispersive Spectroscopy Performed on a Scanning-Transmission Electron Microscope

“…A dry 3 He-4 He dilution refrigerator (DR) can ensure the long-term temperature stability of a TES microcalorimeter without consumption of liquid helium. In the prototype of the TES microcalorimeter EDS system mounted on the TEM [5], a Gifford-McMahon (GM) cryocooler split-type dry DR using a remote helium cooling loop system was developed to maintain the temperature of the TES microcalorimeter [6]. To reduce the noise and vibrations generated by the GM cryocooler, the DR was separated from the GM cryocooler.…”

“…Therefore, we have conducted development of a TES microcalorimeter EDS system operating on a TEM. Hara et al reported on a prototype of the TES microcalorimeter EDS system mounted on the TEM [5]. Later research achieved an X-ray energy resolution of 7.6 eV FWHM using a TES microcalorimeter EDS system operating on the TEM [6].…”

Design and Performance of a TES X-ray Microcalorimeter Array for Energy Dispersive Spectroscopy on Scanning Transmission Electron Microscope

“…We have been developing a STEM-EDS system utilizing a TES X-ray microcalorimeter [2,3]. When we introduced a single pixel TES detector for STEM, we could achieve an energy resolution of 8.9 eV [4].…”

Development of a TES Microcalorimeter with a Mushroom Shaped Absorber Deposited on an Insulating Layer in an Overhang Region

“…We have conducted research and development of a transition edge-sensor (TES) microcalorimeter system performed on the TEM [2]. The TES microcalorimeter is placed outside the TEM column to avoid the influence of the magnetic field generated by the objective lens of the TEM.…”