No abstract available

No abstract available

[en] Moessbauer effect probability in metallic tin is investigated at up to 4 kbar hydrostatic pressure for two crystallographic directions: [001] and [100]. Baric dependence of the Moessbauer effect anisotropy is detected: f₀₀₁/f₁₀₀ relation changes from 0.65 value at P₁ atm up to 0.90 at P=40 kbar. Dependence f on pressure is explained by the model of tin lattice dynamics suggested by Brovman and Kagan

[en] This paper discusses the control process of the radioactive Moessbauer nuclei spontaneous decay probability. The possibility of using this effect in order to produce an optimized gamma-laser is considered. For the first time, the experiment has shown radioactive lifetime doubling for ⁵⁷Fe nuclei and a general lifetime increase (including conversion and non-Moessbauer decay channels) by 2%

[en] The investigation of the Moessbauer effect in paratellurate polycrystals at hydrostatic compression up to 30 kbar is carried out. The dependence of the Moessbauer effect probability on pressure in mono- and polycrystals up to 50 kbar. The presence of the second-type phase transformation at 10 kbar is confirmed. Above 10 kbar the monocrystals fracture has been found

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[en] Ultrasound effect on the dynamic diffraction of Moessbauer gamma quanta in a silicon monocrystal is studied. Complete intensity and its elastic part for (111), (333), (444) and (22-bar0), (4-bar40) reflexes are measured in the Bragg geometry under effect of high-frequency US (transverse waves). A reduction and oscillation of elastic scattering intensity are observed with US amplitude growth which contradicts the results of the previous works (1,2). 4 refs., 2 figs

[en] The Moessbauer effect probability is measured in single crystal tin samples oriented in the (100) and (001) planes under hydrostatic pressure up to 40 x 10⁸ Pa. It is found that the anisotropy of the probability f₀₀₁/f₁₀₀ changes from 0.65 ± 0.02 at P = 0 to 0.90 ± 0.02 at P = 40 x 10⁸ Pa. The experimental data for single crystals and polycrystals of tin under pressure are theoretically explained using the Brovman-Kagan model of lattice dynamics. (author)

No abstract available

[en] The paper discusses the theory and experiments on controlling the probability of spontaneous gamma decay and lifetime of radioactive and excited nuclei. The phenomenon of nuclear decay controlling is a result of interaction of these nuclei with zero-energy electromagnetic modes, which in turn interact with the controlling resonant screen. The most significant influence on the nucleus spontaneous decay process will be realized in case when these modes occur to be mutually synchronized. In this case the radiative lifetime may be increased by many orders of magnitude. The phenomenon of gamma decay controlling was experimentally studied by Moessbauer spectroscopy. In experiments with gamma sources Co⁵⁷(Fe^57*) or Sn^119m and absorbers Fe⁵⁷ or Sn¹¹⁹ we have discovered the change (increase) of Moessbauer radiative lifetime of excited nucleus by 20 100 % and total lifetime (including non-Moessbauer radiation and electron conversion) by 0.6-2.0 %. The creation of optimal systems for controlled utilization, transportation, treatment and storage of gamma-radioactive waste by this method of controlled gamma decay is also discussed. (author)