Evaluation of energy-dispersive X-ray spectrometer with transition-edge sensor microcalorimeter on scanning transmission electron microscope for detection of low-concentration phosphorus in Fe-P alloy

An energy-dispersive X-ray spectrometer using a transition-edge sensor microcalorimeter with a scanning transmission electron microscope was applied to detect low concentrations of phosphorus (P) in an Fe-P-Mo-Mn alloy. The high energy resolution of 7.2 0.9 eV was demonstrated in the measurements of P K alpha signals, which were not visible in the spectra for a conventional silicon drift detector. The P detection limit estimated from the minimum mass fraction improves with the measurement time and is expected to be below 0.005 wt%.