The double-slit dynamical X-ray diffraction in the transmitted and diffracted beams is investigated. The features and differences of the intensity distributions in both beams is investigated. The expressions for the period of the obtained interference fringes are found. The intensity distributions based on numerical calculations are presented and compared with theoretical predictions obtained...
According to the existing model, the low-angle twist boundary is a two-dimensional superlattice, formed by a net of two mutually perpendicular arrays of screw dislocations, so that in a given array the dislocations have the same Burgers vectors. In this work, we study the problem of spherical X-ray wave diffraction by a crystal with a low-angle twist boundary perpendicular to the crystal...
When an electromagnetic wave (EMW) and an acoustic wave (AW) propagate simultaneously in the same region of a crystal, an acousto-optic (AO) interaction arises between them.
As an AW propagates through a crystal, it modulates its dielectric permittivity , which is the primary mechanism responsible for AO interaction, widely used in practical applications.
This study theoretically...
In this work, the Fraunhofer diffraction of a plane electromagnetic wave obliquely incident from a homogeneous, isotropic, and non-gyrotropic medium onto a slit is theoretically examined. Behind the slit, there is a similar medium that differs in its optical parameters from the medium from which the electromagnetic wave is incident. The refractive indices of both media are arbitrary .
...
Radiation Technologies in Environmental Science have demonstrated diverse developmental directions. This study focuses on and examines outcomes that have led to advanced technological solutions. The use of ionizing and non-ionizing radiation to monitor, treat, or analyze environmental components, nowaday, is extremely important. These methods are often non-invasive and highly...
This paper presents the results of an experimental study on the effect of a temperature gradient on the characteristics of asymmetric X-ray reflection in quartz single crystals (X-cut) in the Laue geometry.
The presence of a temperature gradient induces bending of the atomic planes and a change in the interplanar spacing across the thickness of the crystal, which in turn affects the...
As a development of the previous investigation on a specific intermolecular interaction in nematic liquid crystal (NLC) systems, new results of the experimental studies of the dielectric permittivity in NLCs based on biphenyls in the LC state and during the LC โ IL phase transition are discussed in this work. Dielectric measurements were carried out on a frequency range from 10 to ใ10ใ^4 Hz...
The subject of the present study is nonlinear optical (NLO) crystals: L-nitroarginine perchlorate (L-NNAยทHClO4) (I) and L-nitroarginine tetrafluoroborate (L-NNAยทHBF4) (II). The crystal and molecular structure of (I) and (II) crystals were determined by the single crystal X-ray diffraction method at 120K. These crystallize in the monoclinic system with space group P21 and Z=2. Unit cell...
The peculiarities of X-ray diffraction from atomic planes of the same family in different cuts of quartz single crystals under the temperature gradient are investigated. Quartz single crystals have the form of rectangular parallelepiped plates with X- and Z-cuts, one edge of which (heated) was oriented parallel to the reflecting planes (101ฬ 0). The experiments were carried out using collimated...
A single crystal X-ray diffraction method has been developed to determine the hard X-ray spectrum with high resolution. The design and performance of the wavelength-dispersive spectrometer are based on diffraction by bent crystals in Laue geometry. It is shown that in this case we lose intensity, but have approximately twice the wavelength-dispersion as in the von Hamos geometry. The...
The Reciprocity of Illumination and Observation Points in Diffraction Patterns with Maxima
A.Zh. Khachatrian, G.P. Vardanyan, O.A. Zadoyan
National Polytechnic University of Armenia, 105 Teryan St., Yerevan 0009, Armenia
This paper examines the problem of identifying structural features of molecular formations or structures based on diffraction patterns produced by their...
Purpose: This study aims to evaluate the effectiveness of various shielding configurations in attenuating proton radiation and secondary particles, using Monte Carlo simulations. The focus is on comparing single-layer concrete shields with multilayer combinations involving concrete, iron (Fe), and polyethylene (PE).
Methods: Monte Carlo simulations were performed using the PHITS code to model...
Regression models and artificial neural networks (ANNs) are among the most commonly employed techniques for predicting the dynamics of natural and industrial phenomena [1]. In eastern Sudan, radioactivity levels in areas affected by gold mining and other industrial activities were forecast using multiple regression and artificial neural networks. We developed multiregression and ANN models...
Purpose: In proton therapy, secondary particles such as neutrons and gamma rays are unavoidably produced through nuclear interactions, potentially contributing to out-of-field dose and biological risk. This study aims to evaluate the energy spectra and dose contribution of secondary neutrons and gamma rays generated within a water phantom during proton irradiation using detailed Monte Carlo...
nuclear medicine departments in Saudi Arabia over six years. Optically stimulated luminescence (OSL) dosimeters(AL2O3:C) (Nagase Lindauer, LTD (Japan)), was used to quantify the annual effective doses (Hp (10)) for A cohort of 16 workers including nurses (n=3, 18.75%), physicians (n=1, 6.25%), medical physicists (n=3, 18.75%), and technologists (n=9, 56.25%).The overall mean ยฑ SD effective...
The probabilistic appearance of the dependence of the breakdown voltage (electrical strength) of a dielectric located between the circles of a capacitor on the thickness in homogeneous and inhomogeneous fields for dielectric layers in the range from 0.1 mm to atomic thickness is considered. The results of already known experiments and an analytical view of the probability density of their...
Abdulaziz Alsugair2, Nasser Alaboudi1, Fahad Alothaim1*, Abdulrahman Almutairi5, Abdulaziz Almosabahi3, Abdullah Aldosari3, Sarah Albahiti4, Yusuf Alkadhi2, Belal Moftah2, Mohammed Alshabanah2, Saad Aldelaijan2, Noor Alnaimy5, Maryam Alhashem5, Abdulrahman Alkhalifa6, Abdulrahman Algeer7, Ayman Alkhadra8, Ahmed Alomrani9, Mohammed Alkhorayef10, Mohammad Ghrawi1, Abdulmajeed Almansour1,...
H. V. Vasilyan*, H. I. Badalyan, T. V. Ohanyan, S. J. Sedrakyan, E. Aleksanyan, N. B. Margaryan
A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute), 2 Alikhanyan Brothers, Yerevan, Republic of Armenia, 0036
Graphene was synthesized via an efficient, low-temperature liquid-phase exfoliation technique and then characterized using a suite of analytical methods. Raman...
T.V. Ohanyan*, H.I. Badalyan, H.V. Vasilyan, S.J. Sedrakyan, E. Aleksanyan, N.B. Margaryan
A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute), 2 Alikhanyan Brothers, Yerevan, Republic of Armenia, 0036
Grapheneโs outstanding physical characteristicsโmost notably its ultralight weightโmake it an ideal candidate for space based technologies. Yet, the effects of proton...
The paper proposes a new method for visualizing phase-contrast images of polymeric substances using an X-ray interferometer, which makes it possible to determine some of their properties. In particular, based on a three-crystal (two-beam) interferometer, the refractive index and density of polymers were determined by analyzing changes in interference (moirรฉ) patterns. A special device (phase...
The possible mechanisms of the influence of ionizing radiation (IR) on the structure and properties of the phospholipid bilayer were studied by computer simulation, optical polarization microscopy, and X-ray diffraction simultaneously at large and small angles. Three mechanisms of the influence of IR on model membranes obtained in an aqueous medium of an amphiphilic substance have of different...
The subjects of the present study are L-arginine sulfates (LASโ2H2O & LAS) and L-nitroarginine sulfosalicylate (L-NNAโSSA). The thermal properties, vibrational spectra, UV-Vis transmittance spectrum and second harmonic generation activity were experimental studied. The crystal and molecular structure of crystals were determined by the single-crystal X-ray diffraction method. The optimized...
Accurate quantification of Lu-177 uptake in radionuclide therapy requires precise calibration of SPECT/CT systems. This study aimed to determine calibration factors (CF) and recovery coefficients (RC) using Jaszczak and NEMA Image Quality phantoms under standardized acquisition and reconstruction protocols. Lu-177 SPECT/CT was performed with a dual-energy window protocol: main photopeak (208...
In this paper, the results of the studies of fine structures of X-ray diffraction patterns formed in the X-ray 3-block defocused (violated ideal geometry) interferometers, as well as a new method to record these structures, are presented. To implement this method, a monolithic 4-block X-ray diffraction system is proposed and successfully applied, in which the first 3 blocks are thin and set up...
Computed tomography (CT) is a vital diagnostic tool in pediatric medicine, but its associated ionizing radiation raises concerns about long-term cancer risks. Children are particularly vulnerable due to their rapidly dividing cells and longer life expectancy for radiation-induced effects to manifest. Epidemiological studies, including extensive cohort analyses, suggest a small but...
T.M. Bakhshiyan1,2*, G.H. Hovhannisyan2
1Institute of Applied Problems of Physics
of the National Academy of Sciences of the Republic of Armenia,
25 Hrachya Nersisyan, Yerevan, Armenia, 0014
2Yerevan State University, 1 Alex Manoogian Str., Yerevan, Republic of Armenia, 0025
Given the growing prospects for the widespread use of isotopes in nuclear medicine, such as in SPECT/CT and...
