Half-life and X-ray emission probabilities of 55Fe.

The X-ray emission probabilities of the Mn-K(alpha) and Mn-K(beta) radiation in the decay of 55Fe were measured with a calibrated Si(Li) spectrometer, resulting in 0.245(7) and 0.0338(9), respectively. A half-life of 1003.5(21) day was measured using the same detector.

Comparison of measured and calculated emission probabilities for K and L X-rays following radioactive disintegration processes.

The program EMISSION has been developed at the Physikalisch-Technische Bundesanstalt (PTB). It allows emission probabilities to be calculated for K and L X-rays following radioactive disintegration processes. This program was already applied to the calculation of total K X-ray emission probabilities for six radionuclides. The results are found to be in reasonable agreement with measured values. In order to check the validity of this program also for the individual components of K and L X-rays, calculated emission probabilities of K X-ray components (139Ce, 203Hg) and L X-ray components (139Ce, 203Hg, 241Am) were compared with remeasured (139Ce, 203Hg) and already available (241Am) emission probabilities, measured earlier at the PTB. In most cases there is an agreement within the standard uncertainties of the measured and calculated values, usually within 1-5%. Larger deviations, not covered by three times the standard uncertainty have been found for some weak lines.

Standardisation and decay data of 177Lu and 188Re.

The activity values of 177Lu and 188Re standard sources were measured using the 4pibeta-gamma-coincidence method and by liquid scintillation counting. The X- and gamma-ray emission probabilities per disintegration were determined by means of photon spectrometry with calibrated Ge and Si(Li) detectors and using the pertinent activity values. The half-lives were measured with ionization chambers, yielding T(1/2)(177Lu) = 6.646(5) d and T(1/2)(188Re) = 0.70848(9) d.

Standardization and decay data of 237Np.

This paper reports contributions from participants in the EUROMET project (No. 416) which was entitled "237Np research into problems relating to purification, characterization and standardization". Primary standardizations were made by the defined low solid angle, coincidence, 4pi alpha, 2pi alpha and liquid scintillation counting methods. Secondary standardizations were made with calibrated gamma-ray spectrometers. Absolute X-ray, gamma-ray and alpha-particle emission probabilities were also determined. The results for the successful conclusion of both primary and secondary standardization are presented together with the values for alpha-particle and gamma-ray emission probabilities determined in this exercise. Several significant inconsistencies remain with the gamma-ray emission probabilities, and these are highlighted.

Standardization and photon emission probabilities in the decay of 237Np/233Pa

The activity concentration of a 237Np solution was determined by 4pialpha counting, by alpha particle spectroscopy with defined solid angle and by liquid scintillation counting (LSC). These methods yielded results which differ by less than 0.1% from the mean, the relative standard uncertainties being 0.23% (4pialpha), 0.27% (LSC) and 0.5% (solid angle). X-ray and gamma-ray emission probabilities of several transitions were measured using semiconductor detectors.