[en] From hyperfine interaction measurements (PAC) the diffusion of indium in zinc was identified as a two-stage mechanism. The heat of formation of a substitutional dilute Zn(In) alloy is ΔHsub(s)= +0.37(3) eV below 500 K and +0.24(3) eV or +0.18(3) eV above 500 K, depending on the diffusion direction. (author)

[en] Following the recognition of their usefulness by the authorities and the scientific community, automatic water monitoring networks were developed again to be able to measure seawater. For that purpose, they had to be fully autonomous, with low power consumption (solar panel power supply), wireless communicating (satellite, GSM, radio) and very sensitive (a few Bq/m³)

[en] The case of perfect alignment of the magnetic field in the direction of the z-axis of the EFG is considered. Isomeric state produced and aligned by nuclear reaction in a single crystal with hexagonal structure is analysed and experiments at the cyclotron (on isomeric states) of ⁷¹Ge, ⁶⁹Ge are described. 11 refs., 13 figs. (L.I.)

[en] The recently developed level mixing resonance method for the measurement of hyperfine interactions turns out to be a very useful complement to the other methods. Especially in the 'difficult' cases, e.g. when the lifetime of the isomer under consideration is very long or when its spin is very high, this new method can yield valuable, otherwise inaccessible, information. In this paper the concept of this method is briefly presented and some of the recent experiments are described. (orig.)

[en] A new method for measuring hyperfine interactions, especially quadrupole interactions is presented. Level mixings are studied which occur in the hyperfine energy level scheme of nuclei experiencing an axially symmetric quadrupole interaction and a magnetic dipole interaction, the axes of which are slightly misaligned by an angle β. In an angular distribution experiment in which the initial orientation can be produced by any means, the angular distribution of radiation emitted by such nuclei shows resonances under influence of these mixings. This method is particularly useful for the measurement of hyperfine parameters (e.g. the quadrupole moment) of nuclei with a lifetime between 10sup(-6) s and 60 s. Nuclei with very high spin can also be measured by this method. (author)

[en] Level mixing spectroscopy was developed to determine the quadrupolar interaction of high spin isomers in metals. The method has been applied on high spin isomers in Bi and At isotopes in Tl and Bi respectively. 14 refs., 4 figs., 2 tabs. (M.F.W.)

[en] Level mixing resonance method is shortly described and possible applications of this method to solid state and nuclear physics is given. Experiments on isomeric states produced and aligned by nuclear reaction in a single crystal with hexagonal structure are presented. 11 refs., 13 figs., 1 tab. (L.I.)

[en] In atomic spectroscopy, crossings and anticrossings of electronic levels are well studied, and are the source of a considerable amount of information. In the hyperfine splitting of nuclear levels, such crossings and anticrossings can occur as well. Until now, however, these phenomena have been used for hyperfine investigations in only a few cases. In this paper, we study anticrossings (we call them level mixings) which occur in the hyperfine energy level scheme of nuclei experiencing an axially symmetric electric quadrupole interaction and a magnetic dipole interaction, the axes of which are slightly misaligned by an angle β. In an experiment in which the initial orientation can be produced by any means (very low temperature, nuclear reactions, surface interaction, etc.), the angular distribution of radiation emitted by such nuclei shows resonances under the influence of these mixings. In this paper, a qualitative description of the behaviour of these resonances as a function of several (mostly geometrical) parameters is given. The observation of these resonances allows very accurate measurements of hyperfine parameters (especially of the quadrupole frequency) of nuclei with lifetimes shorter than the spin-lattice relaxation time. The less accessible lifetime range between microseconds and minutes is covered by this method. (orig.)

[en] The existent methods for measuring quadrupole interactions are not suited to nuclei with lifetimes in the micro-seconds to minutes region. AD/NQR, a possible candidate in this lifetime gap, has not yet succeeded in overcoming its predicted difficulties. A new resonant method, recently developed and based on the principles of level mixing (cfr atomic spectroscopy) covers this less accessible lifetime range. Many other kinds of resonances can be described according to the level mixing formalism. The particular example of NMR as a level mixing resonance (LMR) is discussed. The underlying theory of LMR and its important consequences, leading to some interesting features of the method, is briefly formulated. Two successfully performed measurements demonstrate the feasibility and the predicted characteristics of this new promising method. (orig.)

[en] In atomic spectroscopy, crossings and anticrossings of electronic levels are well studied, and are the source of a considerable amount of information. In the hyperfine splitting of nuclear levels, such crossings and anticrossings can occur as well. The authors study anticrossings (called level mixings) which occur in the hyperfine energy level scheme of nuclei experiencing an axially symmetric electric quadrupole interaction and a magnetic dipole interaction, the axes of which are slightly misaligned. In an experiment in which the initial orientation can be produced by any means (very low temperature, nuclear reactions, surface interaction, etc.), the angular distribution of radiation emitted by such nuclei shows resonances under the influence of these mixings. A qualitative description of the behaviour of these resonances as a function of several (mostly geometrical) parameters is given. The observation of these resonances allows very accurate measurements of hyperfine parameters (especially of the quadrupole frequency) of nuclei with lifetimes shorter than the spin-lattice relaxation time. The less accessible lifetime range between microseconds and minutes is covered by this method. (Auth.)