Optimization of geometry for radioisotope excited X‐ray fluorescence spectrometry

The source‐sample‐detector efficiency for the recessed source geometry was evaluated, using Monte Carlo techniques, for a variety of samples and sources and found to be superior to that for other geometries in energy‐dispersive X‐ray fluorescence analysis. The samples considered were those with atomic number in the range 14—44 and the radioactive sources were 55 Fe, 244 Cm and 109 Cd. Efficiencies well above 1% can be achieved for the recessed source geometry and samples with atomic number above 20. The values attainable are around four times larger than those for the annular source geometry.