Measurements of photon emission probabilities from the decay of 226Ra and daughters.

X- and gamma-rays spectrometric techniques have been used to determine and improve the photon emission probability data of 226Ra. These values were obtained from 226Ra spectra in radioactive equilibrium with daughters such as 222Rn, 214Bi and 214Pb in the 50-2500 keV energy range. The efficiency calibration of the coaxial and planar Ge detectors took into account correction factors for pile-up losses, attenuation and source geometry effects, and gamma-gamma and gamma-X summation losses. XK emission probabilities were successfully resolved and determined more precisely because of the ability to de-convolute complex regions of the spectrum below 90 keV combined with spectral knowledge of the interferring Pb-XK-rays. The resulting absolute intensities of the main photon emissions of 226Ra and daughters exhibit improvements (+/-0.7% for the smallest uncertainty estimated to one standard deviation) or agree with published data.