Analysis of x-ray spectra excited by x rays, electrons, and protons in monazite

Mineral monazite from Malaysia has been investigated by energy dispersive x-ray analysis employing three different methods: x-ray, relativistic electron and proton induced excitation. An upper limit of 15 ppm has been placed on the possible concentration of the superheavy element with Z=126. [RADIOACTIVITY Monazite (Ce, La, Th)PO4; measured x ray, electron and proton induced x-ray spectra. Deduced upper limit for concentration of element Z=126.] © 1977 The American Physical Society.