Determination of the gamma and X-ray emission intensities of erbium-169

The gamma and X-ray emission intensities of 169Er were determined using radionuclidically pure 169Er. activity the source was standardized by triple-to-double-coincidence ratio technique. Three independent measurements performed to measure calibrated high-purity germanium spectrometers. efficiencies computed with Monte Carlo method validated several experimental measurements. Final results present a large uncertainty reduction compared previous evaluations. per decay are reported as 1.401(40).10−5 for 109.8 keV line 1.513(19).10−6 118.2 line. values obtained lines show discrepancies reference values.