Secondary X-ray Radiation Research Articles

GEANT4 simulation of X-ray radiation for sterilizer based on high-current repetitively pulsed electron accelerator SINUS-320

Secondary X-ray radiation for the sterilizer based on high-current repetitively pulsed electrons accelerator SINUS-320 has been investigated. The energy of accelerated electrons is 500 keV. In this regard, there is a need for radiation protection during operation of the installation, which, in turn, leads to the importance of studying the dose rate of secondary X-ray radiation. The studies were carried out by statistical modeling using the GEANT4 simulation toolkit.

Investigation of the Elemental Composition of Titanium Metal Waste by X-Ray Fluorescence Analysis

The purpose of this work was to study the elemental composition of titanium metal waste to be processed by the method of electroerosive dispersion into spherical powders suitable for additive manufacturing.Methods. When conducting experiments on X-ray fluorescence analysis of chemical composition, pieces of metal waste rods of a titanium alloy of an unknown brand were used. An X-ray fluorescence spectrometer Niton Goldd (USA) was used to determine the elemental composition and percentage of elements in the alloy under study. With this method, X-ray radiation is directed at the sample under study, the reflected wave spectrum is obtained and the characteristics of the spectrum of secondary fluorescent radiation of the sample are analyzed. In this case, electromagnetic waves form secondary X-ray radiation, i.e., characteristic lines that are characteristic of atoms of various elements and have their own individual characteristics. Thus, the elemental composition of the sample under study is determined, and the intensity of these lines shows the quantitative concentration of elements.Results. Using a portable Niton Goldd spectrometer, it was found that titanium metal waste corresponds to the grade of the OT4-0 alloy. The data obtained made it possible to identify samples of the studied metal waste to be processed by the method of electroerosive dispersion into spherical powders suitable for additive manufacturing. As a result of comparing the percentage of chemical elements of the studied metal waste and alloy OT4-0 according to GOST 19807-91, minor discrepancies were found due to the absence of elements such as O, Si, C, N and H. in metal waste. Apparently, this difference is related to their possible presence in small amounts up to 0.1% or complete absence.Conclusion. Renovation of metal waste, including titanium metal waste, will contribute to resource conservation, import substitution and ensuring the technological sovereignty of the Russian Federation.

Automated application of low energy electron irradiation enables inactivation of pathogen- and cell-containing liquids in biomedical research and production facilities

Ionizing radiation is widely used to inactivate pathogens. It mainly acts by destroying nucleic acids but causes less damage to structural components like proteins. It is therefore highly suited for the sterilization of biological samples or the generation of inactivated vaccines. However, inactivation of viruses or bacteria requires relatively high doses and substantial amounts of radiation energy. Consequently, irradiation is restricted to shielded facilities—protecting personnel and the environment. We have previously shown that low energy electron irradiation (LEEI) has the same capacity to inactivate pathogens in liquids as current irradiation methods, but generates much less secondary X-ray radiation, which enables the use in normal laboratories by self-shielded irradiation equipment. Here, we present concepts for automated LEEI of liquids, in disposable bags or as a continuous process. As the electrons have a limited penetration depth, the liquid is transformed into a thin film. High concentrations of viruses (Influenza, Zika virus and Respiratory Syncytial Virus), bacteria (E. coli, B. cereus) and eukaryotic cells (NK-92 cell line) are efficiently inactivated by LEEI in a throughput suitable for various applications such as sterilization, vaccine manufacturing or cell therapy. Our results validate the premise that for pathogen and cell inactivation in liquids, LEEI represents a suitable and versatile irradiation method for standard biological research and production laboratories.

Study of the X-Ray Radiation in Metal-Containing Composites Irradiated with Neutrons and Photons

Secondary X-ray radiation is studied upon the neutron and photon irradiation of composites. The characteristic X-ray radiation and conversion electrons arising from the capture of slowing neutrons of the DT reaction by liquid-crystal DNA–Gd structures are studied for their effects on biological cells. The liquid-crystal structure in the form of microparticles with a volume of 0.1 µm3 contains 10 000 Gd atoms per DNA molecule. During the neutron irradiation of biological samples with a concentration of 1000 DNA-Gd particles per cell, cells are damaged by secondary radiation at a thermal neutron fluence of ~1011 n/cm2. A high-purity germanium (HPGe) spectrometer is used to study the radiation-protective properties and characteristic X-ray radiation of a Pb-containing composite upon irradiation with photons from cobalt-57 with an activity of 100 kBq.

X-ray absorption spectroscopy study of energy transport in foil targets heated by petawatt laser pulses

X-ray absorption spectroscopy is proposed as a method for studying the heating of solid-density matter excited by secondary X-ray radiation from a relativistic laser-produced plasma. The method was developed and applied to experiments involving thin silicon foils irradiated by 0.5–1.5 ps duration ultrahigh contrast laser pulses at intensities between 0.5×1020 and 2.5×1020 W/cm2. The electron temperature of the material at the rear side of the target is estimated to be in the range of 140–300 eV. The diagnostic approach enables the study of warm dense matter states with low self-emissivity.

Characterization and application of hard x-ray betatron radiation generated by relativistic electrons from a laser-wakefield accelerator

The necessity for compact table-top x-ray sources with higher brightness, shorter wavelength and shorter pulse duration has led to the development of complementary sources based on laser-plasma accelerators, in contrast to conventional accelerators. Relativistic interaction of short-pulse lasers with underdense plasmas results in acceleration of electrons and in consequence in the emission of spatially coherent radiation, which is known in the literature as betatron radiation. In this article, we report on our recent results in the rapidly developing field of secondary x-ray radiation generated by high-energy electron pulses. The betatron radiation is characterized with a novel setup allowing to measure the energy, the spatial energy distribution in the far-field of the beam and the source size in a single laser shot. Furthermore, the polarization state is measured for each laser shot. In this way, the emitted betatron x-rays can be used as a non-invasive diagnostic tool to retrieve very subtle information of the electron dynamics within the plasma wave. Parallel to the experimental work, 3D particle-in-cell simulations were performed, proved to be in good agreement with the experimental results.

Secondary X-Ray Environment in the Lower Atmosphere of the Earth during Monsoon Season over Udaipur City (India) in July-September 2006

We present a study on the secondary x-rays of energy band 2−100 keV emitted by the intruded principal pollutant components (gases and minerals) brought up in the lower atmosphere by dust storms, monsoon drift and the gravitational pull on meteoritic showers. On the ground we employed a 1.5 × 1 inch2 NaI crystal in a scintillation detector, suitable for the energy range 2−100 keV of secondary x-rays, providing better energy resolution than a larger sized crystal. In order to eliminate the radioactive background of the Earth, the detector was well shielded on all sides with the help of the lead (Pb) container, except with a small open window at the top to permit only vertically incident secondary radiation. The results from the data analysis obtained during the monsoon over Udaipur city (India) during the period from July to September (2006) have revealed a linear correlation between dust storm cum monsoon clouds and observed luminosities of secondary x-ray radiation from intruded pollutants. We found intense flux of secondary x-rays from the intruded pollutants when heavy dust and monsoon clouds were brought up by dust storms and monsoon drift in the lower atmosphere over Udaipur city as compared to normal days. Thus, secondary x-rays in the environment provide a tool for investigation of local intrusive pollutant components in the lower atmosphere.

X-ray-based displacement measurement for hostile environments

A completely new method of noncontacting, hostile-environment displacement measurement based on the focus and scanning of X rays has been developed and shows promise of overcoming many of the limitations associated with available techniques. The chief advantage lies in the ability to make undisturbed measurements through stratified or flowing gases, smoke and flame. The system is based on the focus and scanning of lowenergy, hard X rays such as those emanating from copper or molybdenum sources. The X rays are focused into a narrow and intense line image which can be swept onto targets that fluoresce secondary X-ray radiation. This radiation is monitored and target-edge position can be determined by measuring the focused image position when the marker begins to fluoresce. The final goal for the system is to be able to conduct macroscopic strain measurement in hostile environments by utilizing two or more fluorescing targets. Current work has been limited to displacement measurement of a single target with a resolution of 0.5 micron. Tests have also been conducted at target temperatures of 1200°C, directly through an open flame. The main advantage of the technique lies in the penetrating nature of X rays, which are not affected by the presence of refracting gas layers, smoke, flame or intense thermal radiation, all of which could render conventional extensometry methods inoperative or greatly compromise their performance.

Radiodermatitis from Diffraction Apparatus

Four cases of radiodermatitis which resulted from misuse of x-ray diffraction equipment are presented. The problem in protection of the worker using x-ray diffractometers does not appear to be primary or secondary x-ray radiation from tube leakage or stray radiation, but rather failure to appreciate the hazards associated with the use of these devices. . When used properly, the x-ray diffractometer is an extremely valuable tool for industry. It behooves the manufacturers of this equipment, as well as the users, to be aware of the hazards and to instruct personnel using these devices to handle them properly. A well- functioning protective shield must be provided and properly positioned before specimens are placed within the unit. Under no circumstances should the housing be removed to permit analysis of specimens of large size nor should specimens be held within the beam. The unit must always be disconnected before adjustments or repairs are made. Had these necessary precautionary measures been taken, the cases of radiodermatitis presented here could have been prevented.