We are developing radioluminescence (RL) and passive light-generating systems for a range of applications, initial studies concerning doped silica optical fibers and time-resolved radiation dosimetry. Merits for biomedical interests include high spatial-and-temporal resolution, wide dynamic range, and real-time operability in various in vivo and ex vivo environments. For Ge-doped optical...
Ionizing radiation, a classified carcinogenic agent, necessitates the implementation of robust radiation protection policies, regulations, and tools to ensure staff safety. Staff members, who work with or in proximity to radiation sources, face the risk of tissue reactions (cataracts and erythema) and cancer induction. To prevent these risks and reduce the probability of cancer and...
Application of methods of X-ray diffraction on laboratory and synchrotron radiation sources, scanning electron microscopy (SEM) allowed to investigate the process of excitation and propagation of different types of surface acoustic waves in piezoelectric crystals (Rayleigh surface acoustic waves, pseudo-surface acoustic waves, Lamb waves).
While SEM method allows to visualize the acoustic...
Overview of the undulator station 1-1 "Microfocus" SRF SKIF, including the implemented set of experimental methods, matched X-ray optical design, operating modes, experimental scenarios and expected parameters of radiation beams on the sample. Optical and thermal-mechanical solutions are substantiated, achievable spatial resolutions are estimated. The feasibility of combining "coherent" and...
The physical processes underlying the high-intensity LASER-matter interaction, the characteristics of the plasma produced, and the multiple applications allowed will be presented.
Coherent sources of radiation, from “free” electrons, are playing a prominent role in Physics and applied science.
Even though they are described as “non-conventional” lasers, they share a noticeable amount of physics with atomic or molecular lasers.
In this lecture we describe the possibility of developing a unified point of view to their treatment, by introducing an appropriate set of...
Cherenkov diffraction radiation (ChDR) appears when a fast charged particle moves in the vicinity of and parallel to a dielectric interface. This is a member of polarization radiation family, because the radiation arises as a result of dynamic polarization of a medium. Coherent ChDR is generated in the wavelength range longer than or comparable to the longitudinal size of the bunch. In this...
Inverse Compton scattering, or as it is often called, Compton backscattering (CB) is one of the most classical and along with that modern subjects of intensive research. In this lecture I will reach out two main areas of research into Compton backscattering.
First, this is the role of CB in astronomy as a source of information about the Universe: cosmic rays, the Sunyaev–Zeldovich effect and...
In my lecture I'll present recent results of the description the optical absorption in lens-shaped ellipsoidal and conical quantum dots for single particle as well as few-particle transitions. It'll be shown that for the specific geometries of quantum dots it is possible to use adiabatic description of such systems. We show that for the pair-interacting few-particle gas we can apply some of...
High-dose-rate (HDR) brachytherapy relies on the precise positioning of a radioactive source through applicators or needles to deliver conformal dose distributions to tumors while sparing adjacent healthy tissue. However, most conventional treatment planning systems do not explicitly model the dose contribution during the entire source transit phase, including entry into the body, movement...
According to the World Health Organization, Saudi Arabia ranked 26th among healthcare levels globally. In 2023, over 18 million radiology procedures were conducted in public and private hospitals. This study aims to estimate radiological procedures frequency and annual collective and per capita effective dose in 2023-2024. Information was collected from King Khalid Hospital, Alkharj, Saudi...
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 → IL phase transition are discussed in this work. Dielectric measurements were carried out on a frequency range from 10 to 〖10〗^4 Hz...
The subject of the present study is nonlinear optical (NLO) crystals: L-nitroarginine perchlorate (L-NNA·HClO4) (I) and L-nitroarginine tetrafluoroborate (L-NNA·HBF4) (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 (101̅0). 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 ± 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
Graphene’s outstanding physical characteristics—most notably its ultralight weight—make 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 (moiré) 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 (LAS∙2H2O & LAS) and L-nitroarginine sulfosalicylate (L-NNA∙SSA). 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...
Present work continues research into the viability of commercially available small dimension carbonaceous media for ionizing radiation dosimetry and radiation damage studies, in part examining the relationship between structural alterations, surface-area-to-volume ratio and carbon content. Dose dependency characterizations have been undertaken for rods and sheets for a range of sources,...
There are two principal ways to achieve ultra-high spectral resolution and maximal diffraction efficiency by blazed (with triangular groove profiles) gratings in the short-wave range (from hard X-rays to vacuum UV): (1) using high-orders diffraction with low and medium groove densities; (2) using first-orders diffraction with high and ultra-high groove densities. Due to the hard-to-solve...
The relaxation of the polarization of the medium as a result of interaction with charged particles leads to the formation of various types of radiation processes. Examples that have been studied in detail in the literature include Cherenkov radiation (CR), transition radiation, and diffraction radiation. The radiation processes mentioned above are also sources of electromagnetic radiation...
In the work within the framework of the gauge symmetry group SU(2)xU(1) the Yang-Mills equation for a single photon is considered. Using the equations in partial derivatives of the first order, an equation for the wave function of the photon is obtained in the form of an equation of the second order taking into account the random environment. The problem of the motion of a single photon in a...
One of the methods of influencing chemical reactions is the use of ultrasound. In this case, most chemical reactions in ultrasonic fields occur in aqueous solutions in the presence of cavitation. It is known that under the influence of cavitation, the direction and speed of chemical reactions occurring in a solution can change significantly. In a number of cases, processes may occur that are...
Graphene, a two-dimensional material composed of a single layer of carbon atoms in a honeycomb lattice, has garnered immense interest for its exceptional mechanical strength, electrical conductivity, and thermal transport properties [1, 2]. In this work, we introduce a novel chlorination protocol—using a specialized liquid-phase treatment—to covalently attach chlorine atoms to graphene, and...
The introduction of ultrasonic vibrations into aqueous solutions can, under certain conditions, lead to the emergence of cavitation, which is expressed in the emergence and collapse of vapor-gas bubbles. In this case, the relatively low average energy of ultrasonic vibrations is concentrated in a small volume of vapor-gas bubbles, reaching high values. As a result, high temperatures (on the...
The results of an experimental study of the spectral distribution of coherent Cherenkov radiation from a pair of electron bunches at the AREAL Accelerator are presented. As a target, a cylindrical Teflon resonator is used. Coherent effects were studied depending on the distance between the bunches, which varied from 2 to 11 ps. Radiation was recorded using QOD (Broadband Quasi- Optical...
We investigate the radiation emitted by a circular annular electron beam propagating parallel to the axis of a dielectric cylinder embedded in a homogeneous medium. Expressions are provided for the potentials and the strengths of the electric and magnetic fields inside and outside the cylinder, considering a general dispersion relation for the two media. The energy flux through the plane...
The identifications of radio sources with angular sizes greater than 20' with quasars are not definite. Quasars cannot be radio sources with such large dimensions. They are very compact not only in the optical domain but also in the radio domain. The reason these radio sources are identified with quasars is due to the presence of a compact radio source within the extended radio source, which...
Abstract
This study assesses radiation doses from the CT component of SPECT/CT scans used in lymphoscintigraphy procedures at a single institution. Data from 130 patients were analyzed, focusing on CT dose metrics, including CTDIvol, SSDE, and DLP, alongside technical parameters such as tube current, collimation, and pitch. Results showed an average CTDIvol of 2.07 ± 1.25 mGy (range:...
Antimony-124 (¹²⁴Sb) is a promising radionuclide for medical applications, particularly in low-dose rate intravascular brachytherapy (IVBT), due to its unique nuclear characteristics. High-energy β-particles (1-2 MeV and higher) are effective for local tumor or restenosis treatment. Low-energy γ-rays (20–300 keV) are suitable for imaging, dosimetry, and monitoring the treatment process without...
Isotopes research and production department at A. Alikhanyan National Science Laboratory (AANL) develops production technologies for Ga, Cu, and Tc radiometals for medical applications [1-4]. The technology is based on solid target irradiation under an 18 MeV proton beam of an IBA C18 cyclotron. The solid target production method leads to higher activity of the final product than the liquid...
Ionizing radiation (X-rays, proton beams) causes structural changes in materials. If a vibrating metallic wire is subjected to such radiation, the natural frequency of the wire is affected as a result of changes in the elastic characteristics of the material. This paper presents the results of experiments on the impact of X-ray radiation in the range of 100-165 keV and a proton beam with...
An experimental investigation of double-slit dynamic X-ray diffraction in silicon crystals demonstrates that Young’s interference fringes can be formed in the cross section of the reflected beam, depending on the distances between the monochromator and the slits, as well as between the slits themselves. The study reveals that the number of observable fringes is influenced by both the crystal...
As is known, the correct choice of the deviation function is very important in order to obtain a certain intensity, spectral and spatial distribution in the diffracted beams formed as a result of X-ray diffraction in deformed crystals. To describe the deviation function, it is sufficient to provide the dependence of the bending radius and interplanar distances of the reflecting atomic planes...
Preclinical positron emission tomography (PET) requires high spatial resolution of the detector. A monolithic scintillator detector block is one of the promising approaches due to its ability to estimate the depth of interaction (DOI) and improve resolution through processing multiple channels and analyzing light distribution. The typical construction of such a block is a matrix of silicon...
Semiconductor nuclear radiation detectors are mostly high-resistance. In order to use very high-resistance detectors, we propose an interface for working with them. We propose a metal-oxide-semiconductor (MOS) structure as a signal-modulating device. The modulation of the MOS capacitance occurs by modulating illumination through an optically translucent metal contact.
High-Resolution Computed Tomography (HRCT) is widely employed in the diagnosis of lung diseases, demonstrating a sensitivity of 95% and a specificity of 85%. Chest CT is frequently used for the diagnosis and monitoring of disease progression, outcomes, and treatment effectiveness. CT is associated with radiogenic risks, which refer to the potential risk of developing cancer due to exposure to...
This study examines the effects of X-ray radiation on DNA and platinated DNA complexes in the presence of AgTOEPyP4 porphyrin. We investigated varying relative concentrations of porphyrin-DNA complexes (r = 0.01, 0.02, 0.04, where r = Cporf/CDNA) and conducted a comparative analysis with platinated DNA complexes (r = 0.025, where r = cis-Pt/CDNA) at a radiation dose of 2 Gy. This approach...
Area monitoring, including environmental and workplace radiation surveillance, is essential in settings with significant radiation exposure such as nuclear reactors, accelerator facilities, contaminated waste sites, and NORM-affected zones in the oil and gas industry. Photon energies in these environments typically range from 20–30 keV to several MeV, requiring dosimetry systems whose response...
S. A. Mahdipour1, M. Shafeei Sarvestani1, S. B. Dabagov2, A. Mowlavi3
1Department of Physics, Bojnurd Student Research Institute, Iran
2INFN Laboratory Nazionali di Frascati, RAS P.N. Lebedev Physical Institute, NR Nuclear University MePhI
3Department of Physics, Hakim Sabzevari University, Sabzevar, Iran
Radiation Pressure Acceleration (RPA) and Target Normal Sheath Acceleration...
Enhanced thermal barrier coatings (TBCs) have the potential to facilitate the operation of next-generation gas turbines at increased combustion temperatures. Considerable research efforts are currently focused on the development of novel materials that surpass the performance of conventional industry standards. Beyond their use in turbines, TBCs are also being investigated for aerospace...
N.V. Maksyuta, V.I. Vysotskii, A.O. Stakhova, D.N. Maksyuta
Faculty of Radio Physics, Electronics and Computer Systems Taras Shevchenko Kyiv National University of Kyiv, Glushkova ave., 4g
This paper continues the study of the features of spectral distributions of spontaneous radiation arising from the channeling of relativistic (including weakly relativistic) electrons in complex...
In this paper the hydrogen-like donor impurity states in CdSe nanoplatelet have been studied using the approximation and numerical methods. The impact of polarization effects caused by a significant mismatch of dielectric constants between the nanoplatelet and the surrounding medium is considered within the framework of the Ritova-Keldysh theory and the Takagahara model. The interaction...
The intraband optical transitions in the strongly oblate asymmetric ellipsoidal GeSi quantum dot (QD) containing pair-interacting heavy hole gas have been investigated. It has been shown, that due to QD specific geometry, the hole gas localization in the lateral plane XOY is described in the framework of the two-dimensional asymmetric oscillator model. Based on the obtained results, Kohn's...
