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Abstract  

Short time activation analysis was applied to the analysis of reactor emergency poisoning solutions, to the analysis of doping elements in small organic semiconductor specimens, for the analysis of high temperature superconductors, and the determination of fluorine in various materials including biopsy samples. All the halogens in waste water were analyzed by a single 20s activation followed by two successive counting periods of 20 and 200s.

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Abstract  

Short-time activation analysis is applied to the analysis of bastnaesite, a rare-earth fluorocarbonate and to uranium analyses of the IAEA ore standards S-7 and S-8, using the 2 and 6s groups of delayed neutrons. It is further applied after enrichment procedures for the determination of B in water by the 20 ms B12 activity of Au in sediments after enrichment on carbon by the 7.8 s197mAu, and of a magnetically-separated heavy fraction of bituminous coal NBS-SRM 2683. Analysis after sensitivity enhancement by repeated activation of subsamples is demonstrated by the determination of Na in K-feldspar by the 20 ms24mNa activity. Analysis after pulse activation is demonstrated on NBS-SRM 1648 Urban Particulate.

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Abstract  

A high-resolution high-rate ψ-spectroscopy system is essential or, respectively, useful in three groups of applications: (1) measurement of nuclides with half-lives of less than one second; (2) Measurement of nuclides with half-lives in the second range at high sample activity; (3) Measurement in the same counting geometry of sample series of highly different sample activities. Examples are given for these applications.

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Abstract  

By means of electrophoretic focussing relatively large amounts can be separated into groups. It is shown that an even better separation can be achieved in a two-dimensional method. The first step of a normal zone electrophoresis is followed by electrophoretic focussing. A sample containing about 0.3 mg metal-ions was separated within 20 minutes. A further advantage over other two-dimensional methods is that the ions are concentrated into small zones by the second step.

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Abstract  

Analyzing environmental samples it is often necessary to determine traces in a matrix or to separate elements easily activated. In this case the detection limit depends on the amount of sample which can be separated. Frequently group separations are sufficient. In this paper we describe the relationship between amount, focussing area and concentration of the electrolytes in electrophoretic focussing. The load capacity and the possibility of group separations are evaluated. It is shown that within 4–5 min up to mg amounts can be separated into at least five groups on a 2 cm broad strip and that the ions are concentrated into small zones with a concentration of up to 1 mg·cm−2.

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Abstract  

A rapid vertical transportation system for irradiation with thermal and fast neutrons is devised and partly constructed for inserting samples into the central thimble of our TRIGA MARK II reactor. Fast neutrons will be produced by a6LiD-converter, so that the energy distribution of neutrons is hardened by absorption of thermal and by the production of 14 MeV neutrons. In pulse irradiation, the 14 MeV-neutron flux is expected to be in the order of 1012/s. The transportation time is to be below 30ms to enable determination of short-lived nuclides down to 15ms. Helium will be used as propelling gas.

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Abstract  

Boron and lithium content in various glass fiber-optics, enamel, and lake sediments were determined by measurement of the Cerenkov-radiation of12b and8Li using the fast rabbit-system of the Atominstitute. The decay-curves were also measured using a dead time correction unit (LFC) and evaluated with respect to interferences of other short-lived nuclides. Simultaneously, γ-spectra of short-lived nuclides were measured with the LFC-system. Main interferences in Cerenkov-counting were observed from28Al and16N. High count-rates were measured correctly with the LFC-system. The halflives of8Li and12B were determined as well as their detection limits in glass and lake-sediments.

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Abstract  

Anthropogenic activity is one of the causes of contamination in the human environment: contamination of air, water, top soils, plants and food products has complex effects on human health problems. Wear and abrasion of various surfaces are constant processes in daily life, and commonly include interaction between human fingers and surfaces of every conceivable material. New methods for investigation of trace transfer processes by human fingers are described. Results of transfer for commonly used metals such as gold, silver, zinc, cadmium, tin, cobalt, nickel, chromium and iron are presented. Relationship between transfer of metals by touch and the general problem of purity in analytical activities is briefly discussed.

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Abstract  

The usual mass of samples for activation analysis is in the range of several milligrams to several hundred milligrams. An improvement of the detection limit by three orders of magnitude is attainable by use of a larger sample size. Limitations of the method due to thermal effects, neutron self-shielding and gamma-ray attenuation during activation and measuring of large organic samples are discussed.

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