A microcalorimeter EDS system suitable for low acceleration voltage analysis

Abstract

AbstractWhen a scanning electron microscope (SEM) is used for analysis, a low acceleration voltage must be used to reduce damage to the sample and to obtain information near the sample surface. Here, a microcalorimeter energy dispersive spectrometer (EDS) system without external cryogen was developed to analyze material samples under low acceleration voltages (<5 kV) with high energy resolution (<20 eV). This EDS system can maintain the operating temperature of the transition edge X‐ray sensor (TES) composing of the microcalorimeter system continuously at 100 mK to measure the X‐ray spectrum with high reproducibility and with high energy resolution. This system resembles a conventional EDS system, but also has a snout to allow the X‐ray detector to be close to the sample. The measured energy resolution was 19 eV (5.9 keV) and the count rate was 300 cps. A thin X‐ray window of aluminum/polyimide bilayer was designed to transmit the X rays at a low acceleration voltage (5 keV). When SUS‐304 was analyzed using this EDS system at an acceleration voltage less than 3 kV, the Cr Lα (573 eV) was distinguished between the closely spaced O Kα (525 eV) and Fe Ll (615 eV)lines, whereas when a solid‐state detector(SSD) was used, it was not distinguished owing to inadequate energy resolution (130 eV). Copyright © 2006 John Wiley & Sons, Ltd.