[en] GEANT 4 simulation toolkit and PhysList QGSP BIC HP for simulate neutron transport and scattering was used. Primary neutron spectrum was modeled similar spectrum of ²³⁹Pu - Be(alpha, n) neutron source. Spectra of neutron passing through the material and scattered were obtained. Number of thermal neutrons after passing various materials were calculated. Detector-dosimeter MKS-01R was used for measurements of the experimental thermal neutron flux from ²³⁹Pu - Be(alpha, n) neutron source. Satisfactory agreement between calculations and experiment was obtained.

[en] Primary and Compton scattered radiation spectra from radioactive source ²⁴¹Am were measured in various geometry and for various targets. Spectral lines intensity of characteristic X-ray radiation (CXR), Compton and Rayleigh scattering are defined. The back scattering peak for a line 59.54 keV was explored. X-ray quanta were registered by the packaged Si detector 300mm and input Al foil 10mm thicknesses. Radiation interaction with targets and detector atoms was simulated in software code GEANT 4 (LE). Simulated spectra, quanta registration efficiency and secondary calculated radiation spectra at 90^o...160^o are compared with experimentally measured energy distributions.

No abstract available

[en] An experimental method of determining the active region thickness of Si planar detector was used. The method based on the dependence the depletion layer thickness from voltage applied to the detector (U = 0...60 V ). The electron energy loss spectra emitted by "9"0Sr -"9"0Y in silicon planar detector were measured. The relative values of most probable energy loss of electrons were de ned for different thickness of detector. The planar detector was considered as a parallel-plate capacitor. The static (capacity) and dynamic (the detection efficiency and the energy deposit) characteristics had a root dependence on voltage.

[en] The bremsstrahlung flux-averaged cross-sections $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)$⟩<!--\; ???\; -->$ and the cross-sections per equivalent photon $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)${}_Q⟩<!--\; ???\; -->$ were measured for the photonuclear multiparticle reaction ${}^{27}$Al(γ, x; x = ${}^3$He + pd + 2pn)${}^{24}$Na at bremsstrahlung end-point energies ranging from 35 to 95 MeV. The experiments were performed using the beam from the NSC KIPT electron linear accelerator LUE-40 with the use of the γ-activation technique. The bremsstrahlung quantum flux was calculated with the program GEANT4.9.2 and, in addition, was monitored by means of the ${}^{100}$Mo(γ, n)${}^{99}$Mo reaction. The cross-sections σ(E) were computed using the TALYS1.9 code with the default options. The measured average cross-sections $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)$⟩<!--\; ???\; -->$ and $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)${}_Q⟩<!--\; ???\; -->$ have appeared to be higher by factors of 2.0-2.4 than the theoretical results. The experimental results have been found to be in good agreement with the data of other laboratories. Consideration is given to special features of calculation of $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)$⟩<!--\; ???\; -->$ and $⟨<!--\; ???\; -->$σ(E${}_{\mathrm{\gamma <!--\; ??\; -->}max}$)${}_Q⟩<!--\; ???\; -->$ for the ${}^{27}$Al(γ, x)${}^{24}$Na reaction, with occurrence of three ${}^{27}$Al photodisintegration channels.

[en] Gamma radiation spectra of 1200 MeV electrons from the single crystals of the beryllium 1.2 mm thick, silicon 1.5 mm and 15 mm thick and tungsten 1.18 mm thick along of the crystallographic axes were measured. Also spectral-angular distributions of gamma radiation from the silicon single crystals 1.5 mm thick along of the crystallographic axes < 100 >, < 110 > and < 111 > were measured. On the basis of these measurements the γ-radiation spectra for the different solid angles up to 6.97×10⁻⁶ sr were obtained.

[en] The method of express analysis provides the measurement of radiation spectra of medical radionuclides by a detection module based on an uncooled silicon planar detector and a ''scintillator-silicon photosensor'' type module. A spectrometric device for express analysis of radionuclide concentration has been developed and its prototyping has been carried out, confirming the operability of the device. The spectrometer analyzer is powered from the USB port of the PC (including a laptop) that provides the possibility of autonomous operation. Test measurements were carried out using the prototype of the spectrometer and X-ray sources, as well as spectral distributions of the radiation of real samples of ⁹⁹mTc in a special container (glass ampoule). For a Si-PIN-detector with a thickness of 300 ?m, the emission spectrum consists of a line of ⁹⁹mTc with an energy of 140.5 keV and two peaks of the characteristic X-ray radiation (CXR) of technetium. The calculation in GEANT4 shows the matching of the ⁹⁹mTc activities obtained from the registration of CXR and the main line. A measurement of the technetium concentration both by the 140.5 keV line and on the CXR radiation was proposed that significantly increases the speed of the data accumulation.

[en] The registration of thermal neutrons by Si planar detector with natural metallic Gd neutron converter was performed. The "2"3"9Pu-Be(alpha, n) fast neutron source with flux 1.13 · 10"5 c"-"1 with paraffin moderator for obtaining of thermal neutrons was used. Control measurements of the thermal neutron flux by detector-dosimeter MKS-01R were performed. Experimental spectra for the reaction Gd(n, gamma)Gd were measured. Spectra consisted of the spectra conversion electrons in energy range 30...200 keV with maximum at energy ∼ 70 keV and Gd CXR lines. Background gamma-radiation was measured by Si PIN detector without Gd plate. Program code GEANT4 for the calculation of the thermal neutron flux was used.

[en] The bremsstrahlung spectra of medium-energy electrons (30…100 MeV) were calculated in GEANT4. Cross sections for photonuclear reactions were calculated in TALYS1.9. A convolution over the energy of the cross sections of one- and many-particle reactions with the bremsstrahlung flux density was performed. The numerical values of the yield of ⁹³Nb(γ,xn)^9-xNb reactions, the activity of irradiated ⁹³Nb targets, and the average reaction cross-sections were obtained. The differences of the bremsstrahlung spectra from electrons with close initial energies were calculated. The shape of the difference spectra was analyzed. The contributions of the quanta of the low energy part of the difference spectrum and the quasi-monochromatic peak of the difference spectrum to the total activity of the targets were compared. An approach for correction of the experimental cross-sections of photonuclear reactions using the method of ''bremsstrahlung spectra difference'' was considered. (author)

No abstract available