Spectroscopic measurement of L X-rays emitted by transuranium elements by using TES microcalorimeter

Energy spectra of L X-rays emitted by ²³⁷Np and uranium isotopes progenies of ²⁴¹Am and plutonium isotopes were measured by a transition edge sensor (TES) microcalorimeter for demonstration of peak separation with high energy resolution. L X-ray photons emitted by transuranium (TRU) elements can to be utilized for a nondestructive TRU monitor. Major L X-ray peaks are clearly distinguished in the energy spectrum of L X-rays obtained by the simultaneous measurement for radiation sources of ²⁴¹Am and plutonium isotopes. The value of full width at half maximum energy resolution is 60.21 eV for a peak corresponding to Np L _β1 X -rays of 17.751 keV in ²⁴¹Am source measurement. Comparable energy resolutions were obtained in other experiments. This measurement demonstrated separation of ²⁴¹Am and plutonium isotopes by L X-ray spectroscopy using TES microcalorimeter.