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[en] A portable, field analyser devoted to fast qualitative and quantitative determination of cassiterite, which is the only tin compound of economic use in industry was made. This analyser differs from other similar ones described in the literature through the fact that pulses are cumulated only as long as the vibrator speed ensures a complete cancelation of the resonance condition. A NIM analyser was also manufactured which allows a qualitative determination of 2-3 iron compounds in a given sample, as well as of the total iron content. Working in geometry transmission and constant velocity regime, this analyser joins the inconstancy of a laboratory Moessbauer spectrometer with the swiftness and simplity of a specialized Moessbauer spectrometer. Analysis of the main factor that affects the qualitative and quantitative cassiterite determinations: sample structural composition, spectrometer calibrating, a.s.o. Determination accuracy is similar to those reported in the literature. Sample structural composition must be smaller than 0.1 mm for the qualitative and quantitative determinations of iron or total iron compounds. Data accuracy is similar to those reported before, but obtained by means of area measurements. As a consequence of the previous results, we have looked for the existence of some new phases in industrial Fe-C and Fe-Si steels or some new compounds appearance in the samples subjected to coroding. (author)

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[en] This proceedings include the 8 lectures presented at the School on Applications of Nuclear Gamma Resonance Spectroscopy (Moessbauer Spectroscopy) held in ICTP Trieste, between 11-16 August 1986. A separate abstract was prepared for each of those lectures

[en] Method for compensation of isomeric shift of lines observed during operation of resonance detectors being part of spectrometers of nuclear gamma resonance is suggested. A flowsheet of device permitting to realize the method described is given. The method is based on using the Doppler effect. A source of resonance radiation is moved at a constant velocity, which is choosen so as to compensate energy shift of lines of the source and convertors of the resonance detector. The absorber under investigation is put in motion with a constant acceleration. The resonance detector signals are amplified selected according to amplitude by a discriminator and come to the input of multichannel analyzer operating in the regime of subsequent scaling. Analysis of experimental spectra obtained at velocities of source movement from 0 to +3 mm/s shows that value of resonance absorption effect drops as increasing energy shift in the source-converter system. It is concluded that application of the method described will permit to considerably extend the field of application of resonance detectors in the Moessbauer spectroscopy and investigate in practice all the isotopes having converted transitions

[en] The invention is intended for measuring the intensity of source emission passed through an absorber depending on relative velocity between the source and absorber. Two or several absorbers with the corresponding number of detectors are mounted in the above device for separate simultaneous measuring the spectra of a standard sample and a sample under analysis

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[en] A design of the NP-255 type spectrometer for Moessbauer studies of chemical properties of materials, crystal structure, crystalline and magnetic properties of metals and their components, etc., is described and technical characteristics of the spectrometer are given. (Z.S.)

No abstract available