[en] Reviewed is the transition period in the history of physics between 1895 and 1905, a decade which began 100 years ago and which is characterized by high scientific activity and creativity with significant results for the further development of natural science. A great number of outstanding scientists, especially physicists, worked in this period. Their important discoveries manifest the beginning of the history of isotopic research. 12 refs

[en] G.R. Martin's method of dead-time estimation was found to be very convenient and reproducible. The influence of inexact decay constant and background on the measured dead-time is shown. (Auth.)

[en] A new variational method was applied to determine the half-life of sup(99m)Tc in aqueous pertechnetate solution. It is 6.007 hrs, the error being 0.0018 hrs at a confidence level of 95%. (author)

[en] A brief account of the life and work of the famous scientist is given

[en] The life and work of the physicist Gustav Hertz (1887 - 1975) is described. Early work, Franck-Hertz experiment, work on isotope separation, and educational activities, are all briefly discussed

[en] Besides a compilation of the most usual film thickness measurement methods with stressing the increased importance of the X-ray fluorescence analysis, the authors describe all GDR-standards and numerous foreign standards for the film thickness measurement. Furthermore they describe the requirements on reference materials used for the film thickness measurement by means of ionizing rays and make an offer for the calibration of film thickness reference materials being suitable for various measuring tasks. (author)

[en] An approximation method has been developed for the indirect determination of the primary energy distribution of an X-ray tube. The method is based on absolute XRF yield measurements of thick pure element specimens which may be carried out by a Si(Li) detector. (author)

No abstract available

[en] The method for determination of thickness and composition of electrodeposited brass coatings is based on X-ray fluorescence analysis but without its expensive detector systems. The measuring accuracy reached is sufficient for controlling the coating process

[en] Among the decay constants for the internal conversion of /sup 99m/Tc the values obtained from metallic samples are subject to unusually high scattering. Some measurements reveal an interdependence between this scattering and certain sample parameters (thickness, homogeneity, degree of reduction). On the basis of a theoretical scattered wave pattern for the chemical effects on the internal conversion of /sup 99m/Tc it is becoming evident that inadequate sample preparation results in a shift of the measured values. Taking this into account, it is possible to use the measurement of decay constants of the internal conversion of /sup 99m/Tc for estimating the quality of thin metallic technetium layers. (author)