Asymmetric Double Quantum Wells with Smoothed Interfaces

We have derived and analyzed the wavefunctions and energy states for an asymmetric double quantum wells, broadened due to static interface disorder effects, within well known discreet variable representation approach for solving the one-dimensional Schrodinger equation. The main advantage of this approach is that it yields the energy eigenvalues and the eigenvectors in semiconductor nanostructures of different shapes as well as the strengths of the optical transitions between them. We have found that interface broadening effects change and shift energy levels to higher energies, but the resonant conditions near an energy coupling regions do not strongly distorted. A quantum-mechanical calculations based on the convolution method (smoothing procedure) of the influence of disorder on the motion of free particles in nanostructures is presented.Comment: 10 pages, 4 figure

Radiation hardness of polysiloxane-based scintillators

Polysiloxane-based scintillators with different contant of aromatic chromophore groups have been obtained. 2,5-diphenyloxazole and its alkyl derivative were used as activators. The optical and scintillation properties of the obtained polysiloxane scintillators have been studied, and their radiation resistance has been determined. The prospect of using the material in fields with high dose loads is estimated.Отримано сцинтилятори на полісилоксанових основах, що містять у своєму складі різну кількість ароматичних хромофорних груп. Як активатори використано 2,5-дифенілоксазол і його алкілпохідне. Вивчено оптичні та сцинтиляційні властивості отриманих полісилоксанових сцинтиляторів, визначена їх радіаційна стійкість. Оцінено перспективу використання матеріалу в полях з великими дозовими навантаженнями.Получены сцинтилляторы на полисилоксановых основах, содержащих в своем составе разное количество ароматических хромофорных групп. В качестве активаторов использованы 2,5-дифенилоксазол и его алкилпроизводное. Изучены оптические и сцинтилляционные свойства полученных полисилоксановых сцинтилляторов, определена их радиационная стойкость. Оценена перспектива использования материала в полях с большими дозовыми нагрузками

Radiation hardness of polysiloxane-based scintillators

Polysiloxane-based scintillators with different contant of aromatic chromophore groups have been obtained. 2,5-diphenyloxazole and its alkyl derivative were used as activators. The optical and scintillation properties of the obtained polysiloxane scintillators have been studied, and their radiation resistance has been determined. The prospect of using the material in fields with high dose loads is estimated.Отримано сцинтилятори на полісилоксанових основах, що містять у своєму складі різну кількість ароматичних хромофорних груп. Як активатори використано 2,5-дифенілоксазол і його алкілпохідне. Вивчено оптичні та сцинтиляційні властивості отриманих полісилоксанових сцинтиляторів, визначена їх радіаційна стійкість. Оцінено перспективу використання матеріалу в полях з великими дозовими навантаженнями.Получены сцинтилляторы на полисилоксановых основах, содержащих в своем составе разное количество ароматических хромофорных групп. В качестве активаторов использовано 2,5-дифенилоксазол и его алкилпроизводное. Изучены оптические и сцинтилляционные свойства полученных полисилоксановых сцинтилляторов, определена их радиационная стойкость. Оценена перспектива использования материала в полях с большими дозовыми нагрузками

Application of the Judd-Ofelt theory to Pr³⁺ ions in Y₂SiO₅ crystals

The results of the Judd-Ofelt theory application to Pr³⁺ doped Y₂SiO₅ are presented. For the first time for this matrix, the Ω₂, Ω₄, Ω₆ parameters have been determined and radiative lifetimes of ³P₀ and ¹D₂ multiplet states have been calculated basing on those parameters. The lifetimes obtained allow the significant influence of the channels of nonradiative quenching for the ³P₀ state to be revealed. A more precise coincidence of calculated and observed spectroscopic characteristics can be obtained only when taking into account the influence of 4f5d electron states on 4f² electron shell properties that is not considered in the framework of the Judd-Ofelt theory

Crystal field parameter calculations for doped Pr³⁺ ion in Y₂SiO₅ crystal

Аb initio calculation of term split of D₂ a Pr³⁺ ion in У Y₂SiO₅ crystal for two non-equivalent optical centers is carried out. The calculated splitting values agree satisfactorily with experimental data and allow to ascribe uniquely the spectral lines belonging to different optical centers.Проведен ab initio расчет расщепления терма D₂ иона Pr³⁺ в кристалле Y₂SiO₅ для двух неэквивалентных оптических центров. Рассчитанные величины расщепления удовлетворительно согласуются с экспериментальными данными и позволяют однозначно соотнести спектральные линии, принадлежащие различным оптическим центрам.Проведено ab initio розрахунок розщеплення D₂ терма iона Pr³⁺ у кристалi Y₂SiO₅ для двох нееквiвалентних оптичних центрiв. Розрахованi величини розщеплення задовiльно узгоджуються з експериментальними даними та дозволяють однозначно спiввiднести спектральнi лiнii, що належать рiзним оптичним центрам

Diagnostics of sprayed atoms in reflecting discharge plasma by the methodof laser fluorescence spectroscopy

The study deals with sprayed atoms occurring as a result of interaction of hydrogen plasma with binary coatings. The work is aimed at development of the near-wall plasma diagnostics method based on the method of laser fluorescence spectroscopy of impurity atoms. A diagnostics complex of periphery plasma of fusion reactors is created. Composite materials erosion mechanism is studied, average velocities of outflow of titanium sprayed atoms are determinedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Plastic scintillator enriched Gd-containing nanoparticles

Polystyrene compositions containing GdF₃ nanoparticles stabilized by ammonium di-hexadecyldithiophosphate and fatty aromatic phosphonic acid (C₆H₅-(CH₂)n-PO(OH)₂, n = 1, 2, 3) were obtained. It was shown that the nanoparticles surface modification by fatty aromatic phosphonic acids with high physical-chemical affinity to polystyrene significantly improves the nanoparticles dispersibility in polymer. The plastic scintillators with content of GdF₃ nanoparticles to 5 wt. % without significant loss of the light yield were obtained

Polymer composite based on polystyrene containing GdF₃ nanoparticles

Polymeric polystyrene-based composites containing GdF₃ nanoparticles stabilized by ammonium dihexadecyldithioposhate and β-styrylphosphonic acid were obtained by radical bulk polymerization. Use of a component β-styrylphosphonic acid, capable of copolymerizing with styrene, as a modifier of GdF₃ surface allows to increase substantially the content of GdF₃ nanoparticles in polystyrene plastic scintillator without changing its scintillations properties

Synthesis and luminescent properties of CaF₂:Eu²⁺ nanocrystals

The synthesis of CaF₂ nanocryatals activated by Eu²⁺ ions and soluble in nonpolar media is described, their luminescent properties are studied. It is shown that in nanocrystals of this type there are some channels of radiationless energy loss. These losses significantly decrease the quantum yield of luminescence of CaF₂ nanocryatals