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Introduction/Method: The suspicion that Napoleon was poisoned by his friend Earl of Montolon on behalf of the English was fostered for centuries. Since it was possible to measure arsenic in [...]

Abstract: A large sample INAA (LS-INAA) was conducted based on available experimental conditions. Four different materials, e.g., a quartz-sand and three wastes from an incineration plant were analyzed on sample size of 1 kg. The neutron flux spatial distribution was determined by irradiation of flux monitors in the sample. The gamma-ray apparent counting efficiency was evaluated based on the effective-solid angle concept, using linear attenuation coefficients calculated from an iteration process. The k 0- and the modified monostandard methods were modified for the LS-INAA. To check the LS-INAA performance, a conventional small sample INAA was carried out for the quartz sand and a waste. All detected elements in the LS-INAA are presented and the discussion is conducted to explore the sources of errors in the LS-INAA. As a pilot experiment, the information from this work will be used in constructing irradiation and counting devices for the new FRM-II neutron source in Garching, Germany.

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Abstract: Stent placement has become an effective treatment for abrupt or threatened vessel closure in recent years. As a preliminary investigation on the allergy problem towards to Ni and Cr metals from implanted stent, the release of the two elements from stents into isotonic NaCl solution was investigated. Trace amounts of Ni and Cr metals released from stents are successfully determined by neutron activation analysis (NAA). An extreme experimental condition is applied in the NAA procedure to reach a low detection limit of 1 ng Ni. A conclusion is given about the influence on the Ni and Cr release from gold coating, from the expansion, and from the different incubation periods.

Abstract: It has been demonstrated that the interferences on64Cu 511 keV line from nuclides having high energy γ-rays can be effectively reduced physically. An INAA procedure is proposed and used to determine trace amounts of Cu in biological and environmental samples, However, due to the fact that the interferences on64Cu 511 keV line are not completely eliminated, the question arises on what is the limit of the non-destructive method for Cu determination. An equation is derived to establish the relation between the minimum detectable Cu concentration and the INAA experimental conditions. Based on this equation, an optimised INAA procedure is worked out and applied to blood analysis. The results show that the optimised INAA procedure is able to determine Cu quantitatively for samples with Na-to-Cu content ratio less than 600–1000.

A direct method for determining ultratrace inorganic impurities in high-purity water is presented, which consists in activation of a large volume of water (250 ml) by reactor neutron activation, subsequent gamma spectrometric assay and concentration evaluation by the monostandard procedure. The method requires neither preconcentration nor postconcentration and provides a sensitivity for a large number of elements in the concentration range of parts per trillion (ppt: 10-12 g/g) or even much less. Using the method, over twenty different ultratrace elements are quantitatively determined in two different high-purity waters, i.e., bidistilled water and water from a Super-Q system. Problems involved in analysing such highpurity waters are discussed.

Abstract: The diffusion behaviour of implanted boron in silicon was investigated using the10B(n,α)7 Li nuclear reaction. An anomalous behavior with a strong reduction of the diffusivity above an effective solubility limit at 1.51019, 61019, and 1.11020 cm−3 was found for annealing temperatures of 800, 900, and 1,000C, respectively.

Abstract: The range parameters of boron in silicon have been measured using the10B(n,α)7 Li-nuclear reaction. The results indicate that the distributions can be perfectly modeled using Pearson IV distributions with 4 moments. The range is very well described by theoretical calculations, whereas the higher moments show a strong deviation from theory.

Abstract: The isotopes3He,6Li,7Be and10B exhibit extremely large cross sections, between 1 and 48 kilobarn, for (n, p) or (n, α) reactions with thermal neutrons. Together with now available extracted thermal neutron fluxes of 10( n·cm−2·sec−1 or more, these reactions present a highly sensitive method of detecting the mentioned light elements in any heavy matrix material. Through the experimentally determined energy losses of the emitted protons or α-particles, also well resolved depth profiles can be obtained, as demonstrated here for some relevant examples from semiconductor and fusion technology.

Abstract: This work demonstrates that the64Cu 511 keV line can be used in INAA to determine trace amounts of Cu in biological and environmental materials. The method to reduce the serious interference in γ-ray spectroscopy from nuclides having high energy γ-rays is discussed. A simple INAA procedure is proposed and examined for 7 different SRM materials. An accuracy and precision better than 3% are achieved for tested samples with Na-to-Cu content ratio less than 1000. The minimum detectable Cu concentrations of less than several ppm are calculated for all the analysed samples. To retain the multi-element capability, the k0-and the modified monostandard methods are applied by using the64Cu 511 keV line as the comparator. With the aid of the program MULTINAA, maximum 32 elements are simultaneously determined with an accuracy better than 5% for most elements.

Abstract: The analytical use of the prompt gamma-rays originating from neutron capture is a valuable completition of the conventional neutron activation analysis. The application of the external radiation tube P2 of the research reactor in Munich, an Am—Be neutron source of 300 mCi and a 1 mg252Cf neutron source is discussed.

Oxygen can be determined by the nuclear reaction 16O (n, p) 16N initiated by fast reactor neutrons. The automatic irradiation and counting system which is used in the Munich research reactor for non-destructive oxygen determination is described. The activation by thermal neutrons is suppressed by the installation of a cadmium shield around the pneumatic tube at the irradiation position. Oxygen has been determined in the presence of many elements to find out which elements disturb the oxygen activation analysis.

Summary The intense fast-neutron fluxes, which are available in nuclear reactors, can be used for rapid and non-destructive activation analysis of many elements. Some elements have even superior detection limits for activation with fast reactor neutrons compared to reactor thermal-neutron activation. Short-lived radionuclides can also be measured using a fast pneumatic tube system. Oxygen can be determined by the nuclear reaction 16O(n, p)16N initiated by fast reactor neutrons counting the high-energy gamma rays of the 7.4 sec nitrogen-16. The method is suitable for determining as little as 10 ppm of oxygen in many types of analytical samples. The fast transfer system, which is used in the Munich research reactor for rapid and non-destructive activation analysis is described. The use of the transfer-system for oxygen activation analysis and problems associated with oxygen analysis are discussed.

The beam tubeP2 of the 4 MW FRM pool reactor was used as the neutron source for this nuclear spectroscopy study. An 8.5 and 13.5 cm lithium drifted germanium detector were used as gamma ray detector to measure the low energy prompt photon emissions from thermal neutron capture in 18 elements (12 rare earth elements) having aσ/Avalue greater than 0.1. The energy region was from 50–500 keV. Energy and intensity of the gamma ray lines are given.

Abstract: Certain elements which are not possible to detect with conventional neutron activation analysis can be measured using thermal neutron-capture gamma-ray analysis. The use of a curved neutron guide at the High Flux Reactor, Grenoble, with a thermal neutron flux of 1.5·1010n·cm−2·sec−1 and the advantage of a low-background counting system (Ge(Li) detector) far from the reactor core are described. Experimental detection limits of a number of elements are given for the low-energy and the high-energy regions. Some applications of the capture gamma-ray method in the whole energy range are studied and are briefly discussed.

Abstract: A rapid method has been developed for the determination of tungsten, especially in rocks. The reaction182W(n, γ)183mW (T=5.3 sec), with a thermal neutron capture cross-section of 0.5 b was used. The samples were irradiated in the fast pneumatic system of the FRM, which is described briefly. The low-energy γ-rays of the isomer183mW were measured by a high-resolving Ge(Li) detector. The sensitivity of the method is 0.1 mg tungsten with an accuracy of about 5%; the minimum concentration is 0.1–0.2% W in geological samples. The analysis time is 2 min per sample.

Summary The possibilities of various methods of surface analysis (Auger electron, ESCA-photoelectron and energy dispersive X-ray spectrometry) on radioactive materials are shown. First results of measurements on fuel elements, dissolution residues and samples of aerosol formation are discussed.