Portable pyroelectric electron probe microanalyzer with a spot size of 40 μm

Abstract

We report a method of reducing the spot size of an electron beam in a portable pyroelectric electron probe microanalyzer (EPMA) and its application to on-site microanalysis. An electron beam with a spot size of 40 μm full width at half maximum was achieved by preventing the production of an electric field on the side of a needle tip set on the pyroelectric crystal in the EPMA by coating the side of the tip with an insulating material. This spot size was approximately 10 times smaller than that previously reported. We were able to acquire a line scan profile of a thin copper line sputtered on a silicon substrate using the portable pyroelectric EPMA. The width of the sputtered copper evaluated from the line scan profile (120 μm) corresponded to that from a line scan profile obtained by conventional stationary scanning electron microscope-energy dispersive X-ray spectroscopy equipment.

X-Ray Excited Optical Luminescence and Portable Electron Probe Microanalyzer–Cathodoluminescence (EPMA–CL) Analyzers for On-Line and On-Site Analysis of Nonmetallic Inclusions in Steel

“…Comparing MgAl 2 O 4 spinel and Al 2 O 3 particles with similar size, such as particles 1 and 4, it could be shown that the XEOL intensity of MgAl 2 O 4 spinel is higher than that of Al 2 O 3 . This trend is consistent with the results that we have previously obtained by investigating the CL spectra of a single particle with the size of approximately 100 μ m consisting of MgAl 2 O 4 spinel and Al 2 O 3 phases; the CL intensity of MgAl 2 O 4 spinel was ~10 times higher than that of Al 2 O 3 (Imashuku & Wagatsuma, 2017). Thus, when we used the digital single-lens reflex camera, the number of particles producing green luminescence was larger than that of particles producing blue luminescence, as shown in Figure 2b, although almost the same amounts of MgAl 2 O 4 spinel and Al 2 O 3 were present in the model sample.…”

“…Cu L, Si K, and Cu K lines were detected in both spectra. The Si K line was attributed to the insulating materials coated on the Pt 0.8 Ir 0.2 wire and the needle holder (Imashuku & Wagatsuma, 2017). The characteristic X-rays of copper (Cu L and Cu K) originated from copper in the model sample.…”

“…The exposure time was 80 s. A platinum–iridium alloy (Pt 0.8 Ir 0.2 ) wire with a sharp tip and its holder were attached on the − z plane of the LiTaO 3 single crystal for elemental analysis of the model sample using the portable EPMA as shown in Figure 2b. The details of the preparation for the Pt 0.8 Ir 0.2 wire with a sharp tip and its holder were reported in our previous paper (Imashuku & Wagatsuma, 2017). The analyzed positions of the sample were controlled with a linear transition manual stage connected to the brass metal rod and monitored using the digital single-lens reflex camera.…”

“…The portable EPMA and CL spectrometer mainly consisted of a pyroelectric crystal, a small rotary pump, a Peltier device, a 3 V battery, detachable vacuum joints, an X-ray detector for EPMA, and optical spectrometer and digital camera as the CL spectrometer. By placing an electroconductive needle with a sharp tip and coating the side of the tip with an insulating material, the spatial resolution of the portable EPMA was improved to 40 μ m (Imashuku & Wagatsuma, 2017), which is sufficient for the analysis of the larger nonmetallic inclusions in steel. There has been research on CL analysis using a stationary CL microscope or CL spectrometer equipped with a scanning electron microscope (SEM) for the identification of nonmetallic inclusions in steel (Yin & Tsai, 2003; Kaushik et al, 2009; Imashuku et al, 2017 a , 2017 b ).…”

Progress in Research and Application of Micro-Laser-Induced Breakdown Spectroscopy

“…In the accumulated 10 pulses, the detection limits to Na and Mg elements reach 2-100 ppm, while the detection limits to elements such as Cu, Si, Ni, Mn, Fe, Al are generally 0.01%-2% [1][2][3][4][5] . Electron beam microanalysis [6][7][8] is the most commonly used microanalysis technology in the world. Representative of them are electron probes or scanning electron microscope X-ray energy spectrum analyzers, although it can give detailed chemical composition information, it is only suitable for the analysis of small-area samples.…”