AbstractA systematic study of Lα/Lβand Lα/Lγx‐ray intensity ratios was undertaken by measuring the characteristic x‐ray intensities in 23 elements over the rangeZ= 55‐80, using a 30 mCi238Pu source of excitation and a high‐resolution Si(Li) detector system coupled to a computer‐controlled multi‐channel analyser. The theoretical predictions due to Scofield were computed for the present energy (weighted average) of 15.28 keV excitation and compared with the experimental values. The experimental values of Lα/Lβand Lα/LγversusZwere fitted to a fourth‐degree polynomial, and most probable values of Lα/Lβand Lα/Lγat eachZwere also