Karsten Kossert

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Radioactive 90Y was standardized by means of 4piBeta liquid scintillation efficiency tracing with a two-phototube counting system. The efficiencies of 90Y and the tracer 3H are related by the CIEMAT/NIST method. The dependence of the calculated efficiency on various shape factors and the importance of accurately measuring the radionuclide impurity of 90Sr(More)
The methods to compute the counting efficiency of electron-capture nuclides in liquid scintillation counting have been improved in several previous studies. The main improvements comprise a more realistic treatment of the ejection of photoelectrons and subsequent rearrangement processes in the atomic shell as well as a more detailed atomic rearrangement(More)
The activity of a (22)Na solution was measured by means of two 4pibeta-gamma coincidence-counting techniques. The first method corresponds to the classical 4pibeta-gamma coincidence counting and requires the beta(+)-branching ratio. The second procedure is based on a variation of the distance between source and gamma detector. The efficiency for detecting(More)
The CIEMAT/NIST and TDCR methods in liquid scintillation counting, initially developed for the activity standardization of pure-beta radionuclides, have been extended to the standardization of electron capture and beta-gamma radionuclides. Both methods require the calculation of the energy spectrum absorbed by the liquid scintillator. For radionuclides(More)
The specific activity of natural 87Rb was measured by means of 4pibeta liquid scintillation counting in a two-photomultiplier-tube spectrometer. 3H-efficiency tracing was used together with the CIEMAT/NIST method to obtain the detection efficiency. For this purpose a new parameterization of the shape factor for the third forbidden non-unique beta-transition(More)
The purposes of this study were to create national activity standards of (64)Cu, to make possible the definition of an international key comparison reference value and to determine the decay data in order to improve the decay scheme. Four laboratories measured the activity of a (64)Cu solution; these results were compared through the International Reference(More)
Liquid scintillation counting techniques combined with the CIEMAT/NIST method have been applied to measure the specific activity of natural potassium salts. Samples have been prepared with three different scintillators. The individual atomic composition as well as the density of the cocktails have been taken into account for the efficiency calculation. With(More)
The Triple to Double Coincidence Ratio (TDCR) method requires a special counting system with three photodetectors. The systems currently used by National Metrology Institutes for activity standardizations are custom built, and up to now the HIDEX 300 SL counter is the only TDCR counter commercially available. At PTB, measurements with a special metrology(More)
In this paper, we apply the CIEMAT/NIST method to the three low-Z electron-capture nuclides 54Mn, 55Fe and 65Zn by using the KLM and KL1L2L3M atomic rearrangement models, respectively. The counting efficiencies are computed with the new code EMILIA, which comprises an improved model for the interaction of low-energy X-rays with the scintillation cocktail.(More)
Samples containing high-energy beta emitters in hydrochloric acid were measured in an in-house built triple-to-double coincidence counter. For the analysis of the results, a new method was developed that is based on a free parameter model. Formulas for the determination of the counting efficiencies were derived assuming a Poisson distribution for the(More)