Search

Germplasm innovation is the cornerstone of breeding, so the X-rays generated by electron accelerators was as a mutagenic tool to explore and optimize the application strategies of breeding materials. Initially, through meticulous adjustments, the semi-lethal/semi-dwarf dose thresholds were established for diverse treatment subjects. Subsequently, fine-tuning of irradiation intensities was performed to elicit genetic variations, and the treated materials maintained high survival rates. Furthermore, the optimal timing and approach for material treatment were explored to maximize the efficiency of irradiation-induced mutations. The irradiation treatments were implemented on a wide range of crops, achieving notable preliminary successes. Maize plants exhibited pronounced dwarfing after irradiation, and the degree of dwarfing was positively correlated with the treatment intensity. After irradiation, soybean plants exhibited reduced plant height and enhanced insect resistance, indicating the induction of favorable traits through irradiation. Quinoa treated by irradiation manifested extensive genetic variations of multiple traits, including plant height, leaf color, flower color and panicle morphology. Through specific irradiation treatments and screening, rice plants with significant herbicide resistance were successfully bred, offering a novel strategy for weed management. Above results not only enriched the theoretical framework of mutagenic breeding, but also opened up new avenues for crop genetic improvement and variety innovation. [ABSTRACT FROM AUTHOR]

Investigation of the physical characteristics of mineral artifacts was undertaken with purpose of development of dating by the electron paramagnetic resonance (EPR) method in a new direction, by means of analysis of spectra of the carbonate probes from the surface of archaeological artifacts. The artifacts – samples of layers from the surface of ceramics and stone tools, containing impurities of quartz and alumosilicates, have been tested. For obtaining the physical characteristics and dating the complex of the methods and equipment has been used which allowed us to reveal specialties of mineral content and structure of the surface. There were chosen optimal conditions for registration, distinguishing and identification of the EPR signals from the paramagnetic centers. Applying of radiation of the ILU-10 accelerator with converter and consequent EPR-studying allowed to estimate the age of artifacts.

Background: An ultra‐high dose rate (UHDR) electron accelerator for FLASH radiotherapy (RT) produces very intense bremsstrahlung by the interaction of the electron beam with objects both inside and outside of the accelerator. The bremsstrahlung dose per pulse is typically 1–2 orders of magnitude larger than that of conventional RT x‐ray treatment of the same energy, and for electron energies above 10 MeV, the bremsstrahlung produces substantially more induced radioactivity outside the accelerator than for conventional RT. Therefore, a thorough radiation safety assessment is mandatory prior to the operation of a UHDR electron accelerator. Purpose: To evaluate the radiation safety of a prototype FLASH‐enabled Varian TrueBeam accelerator and to develop a general framework for assessment of all key radiation safety properties of a UHDR electron accelerator for FLASH RT. Methods: Production of bremsstrahlung and induced radioactivity by a UHDR electron accelerator is modeled by various analytical methods. The analytical modeling is compared with National Institute of Standards and Technology (NIST) bremsstrahlung yield data as well as measurements of primary bremsstrahlung outside the bunker and induced radioactivity of irradiated thick targets for a FLASH‐enabled 16 MeV Varian TrueBeam electron accelerator. In addition, the analytical modeling is complemented by measurements of secondary bremsstrahlung inside/outside the bunker and neutrons at the maze entrance. Results: Calculated bremsstrahlung yields deviate maximum 8.5% from NIST data, and all measurements of primary bremsstrahlung and induced radioactivity agree with calculations, validating the analytical tools. In addition, it is found that scattering foil bremsstrahlung dominates primary bremsstrahlung and the main source of secondary bremsstrahlung is the irradiated object outside the accelerator. It follows that primary and secondary bremsstrahlung outside the bunker can be calculated using the same simple formalism as that used for conventional RT. Measured primary bremsstrahlung tenth‐value layers for concrete of the simple formalism are in good agreement with NCRP and IAEA data, while measured secondary bremsstrahlung tenth‐value layers for concrete are considerably lower than NCRP and IAEA data. All calculations and measurements form a general framework for assessment of all key radiation safety properties of a UHDR electron accelerator. Conclusions: The FLASH‐enabled Varian TrueBeam accelerator is safe for normal operation (max. 99 pulses per irradiation) in a bunker designed for at least 15 MV conventional x‐ray treatment unless the UHDR workload is much larger than the x‐ray workload. A similar finding applies to other UHDR electron accelerators. However, during beam tuning, radiation survey, or other tests with extended irradiation time, the UHDR workload may become very large, necessitating the implementation of additional safety measures. [ABSTRACT FROM AUTHOR]

An experiment was carried out to study the feasibility of 99Mo production using an electron accelerator based epi-cadmium neutron source. The neutrons were produced by the interaction of bremsstrahlung end-point energy of 10 MeV with BeO blocks and the neutrons thus produced were moderated using High Density Polyethylene blocks. Effective cross-section of 98Mo(n,γ)99Mo reaction was measured using foil activation method. An enhancement in the effective cross-section due to resonances in the epi-cadmium region was observed. The photons and neutron production/transport in the experimental set-up were simulated using the FLUKA Monte Carlo code. The simulations were found to be in good agreement with the experimental findings. [ABSTRACT FROM AUTHOR]

A liquid helium-free cryostat for radio frequency (RF) test of the superconducting cavity is designed and constructed. Gifford-Mcmahon (G-M) cryocoolers are used to provide cooling capacity, and the heat leakage at 4 K is less than 0.02 W. Vertical and horizontal tests of two Nb3Sn cavities are carried out in the cryostat with different surface treatments outside the cavities. Both of the cavities achieve stable continuous wave (CW) operation. A novel treatment, which cold-sprayed a 3.5 mm thick Cu layer onto the outside of the cavity, enables the maintenance of an average temperature of 5.5 K in the cavity at a RF loss of 10 W, implying that the thermal stability and uniformity of the cavity has been significantly improved. Through the synergistic control of four metal film resistors, a cooling rate of 0.06 K/min near 18 K is realized, and the cavity temperature gradient is reduced to 0.17 K/m, which effectively improves the RF performance of the cavity. The maximum E a c c of the cavity reaches 3.42 MV/m, and the Q 0 is 1.1 × 109. An electromagnetic–thermal coupling simulation model for the superconducting cavity is established and is in good agreement with the experimental results. The simulation results show that the cavity with a Cu-spraying treatment and the thermal links of 5N Al can satisfy the E a c c of 10 MV/m under conduction cooling. [ABSTRACT FROM AUTHOR]

A new non-destructive method has been proposed to determine the radioactivity of long-lived nickel radioisotopes produced in nuclear reactor metallic structural materials. We offer to use an electron accelerator and photonuclear reactions to determine the activity of 63Ni in spent reactor steel and alloys by the 60Co activity. The relative activity measurements allow to ignore factors such as material heterogeneity, differences in sample density and chemical composition. Using a semiconductor spectrometer with an HPGe detector, the developed method has an uncertainty of 5–10% and a sensitivity of 0.5 Bq g–1. It makes it possible to simplify the identification and control of 63Ni in metallic structural materials of nuclear power units and various types of radioactive waste. The proposed method was tested on RBMK-1000 and WWER-1000 reactor samples. [ABSTRACT FROM AUTHOR]

To advance high-energy atmospheric physics, studying atmospheric electric fields (AEF) and cosmic ray fluxes as an interconnected system is crucial. At Mt. Argats, simultaneous measurements of particle fluxes, electric fields, weather conditions, and lightning locations have significantly enhanced the validation of models that describe the charge structures of thunderclouds and the mechanics of internal electron accelerators. In 2023, observations of the five largest thunderstorm ground enhancements (TGEs) revealed electric fields exceeding 2.0 kV/cm at elevations just tens of meters above ground—potentially hazardous to rockets and aircraft during launch and charging operations. Utilizing simple yet effective monitoring equipment developed at Aragats, we can mitigate the risks posed by these high-intensity fields. The Mendeley dataset, comprising various measured parameters during thunderstorm activities, enables researchers to perform advanced correlation analysis and uncover complex relationships between these atmospheric phenomena. This study underscores the critical importance of integrated atmospheric studies for ensuring the safety of high-altitude operations and advancing atmospheric science.

Using the Monte Carlo method, the impact of the angular distribution of the electron source on the dose distribution for the 2.5 MeV ELV electron accelerator was explored. The experiment measured the 3-D dose distribution in the irradiation chamber for electron energies of 1.0 MeV and 2.5 MeV. The simulation used the MCNP6.2 code to evaluate three angular distribution models of the source: a mono-directional beam, a cone shape, and a triangular shape. Of the three models, the triangular shape with angles θ = 30°, φ = 0° best represents the angle of the scan hood through which the electron beam exits. The MCNP6.2 simulation results demonstrated that the triangular model is the most accurate representation of the angular distribution of the electron source for the 2.5 MeV ELV electron accelerator.

The Swiss Light Source (SLS) is an electron synchrotron at the Paul Scherrer Institute established in 2001. With an electron energy of 2.4 GeV and 16 operation beamlines, it provides photons for research in various fields of science. This paper describes the approach for the dismantling of the SLS storage ring from the material clearance point of view. It summarizes the general methods used for clearance and their application to the material to be cleared due to the SLS 2.0 upgrade. The experimental research described in this work confirms the applicability of the developed dismantling and clearance approach. [ABSTRACT FROM AUTHOR]

Radiation treatment of food makes it possible to solve some issues of the food industry, including suppression of pathogenic microbial contamination, retention of the nutritional value of the product, and increase in its shelf life. This treatment method in combination with highly sensitive methods of gas chromatography–mass spectrometry makes it possible to reveal biochemical markers of irradiation treatment in meat products with moderate fat content, such as chicken and turkey. This work describes the experimental results of the dependences of the content of volatile organic compounds in chilled chicken meat treated with 1 MeV accelerated electrons with the doses from 250 Gy to 20 kGy in two weeks of storage. The content of volatile organic compounds in irradiated and reference food samples has been determined on days 0, 1, 4, 6, 8, 11, and 13 after irradiation treatment. Similar behavior pattern of aldehydes identified in treated poultry meat, namely, hexanal, heptanal, and pentanal, has been determined in two weeks of product storage. An increase in the aldehyde concentration has been detected in samples treated with doses from 500 Gy to 10 kGy on days 1–4 after irradiation. It has been revealed that, with an increase in the irradiation dose the period of aldehyde accumulation in irradiated meat is displaced toward a shorter period of product storage. Thus, aldehydes can be considered as potential markers of irradiation treatment of chicken meat in the first four days after irradiation. [ABSTRACT FROM AUTHOR]

The results of measuring the current density distribution of a wide-aperture electron beam outputted into the atmosphere and generated in an accelerator based on a non-self-sustaining high-voltage glow discharge (HVGD) are described. A self-sustained glow wire discharge with a hollow cathode was used to generate the emission plasma. A comparison was made of the inhomogeneity of the beam current density in the atmosphere in continuous and pulse-periodic emission generation modes. [ABSTRACT FROM AUTHOR]

We consider the possibility of modifying the adhesive properties of polyethylene films by an electron beam in the atmosphere to produce composite materials. The modification was carried out on a wide-aperture (750 × 150 mm) low-energy (up to 200 keV) electron accelerator DUET with a grid plasma cathode based on a low-pressure arc and the output of a submillisecond beam of large cross-section into the atmosphere. By the method of studying the wetting edge angle, it was determined that the modification of polyethylene films in various radiation intervals improves adhesive properties, and the edge angle was reduced from 101° of the original to 65° of the modified ones. Infrared spectroscopy and scanning electron microscopy revealed the formation of oxygen-containing (C=O, C–O) functional groups and an increase in the relative intensity of the absorption bands, which indicates a chemical change in the structure of the surface of the material, contributing to the improvement of adhesive properties. The method of atomic force microscopy revealed a decrease in the greatest height of profile irregularities from 125 to 40.4 nm, which contributes to an increase in the contact area of the adhesive with the surface. Experiments on modification of polyethylene films by a large-section electron beam with atmospheric discharge confirm the possibility of using installations of this type to improve adhesive properties and create composite materials based on them. [ABSTRACT FROM AUTHOR]

A liquid helium-free cryostat for radio frequency (RF) test of the superconducting cavity is designed and constructed. Gifford-Mcmahon (G-M) cryocoolers are used to provide cooling capacity, and the heat leakage at 4 K is less than 0.02 W. Vertical and horizontal tests of two Nb3Sn cavities are carried out in the cryostat with different surface treatments outside the cavities. Both of the cavities achieve stable continuous wave (CW) operation. A novel treatment, which cold-sprayed a 3.5 mm thick Cu layer onto the outside of the cavity, enables the maintenance of an average temperature of 5.5 K in the cavity at a RF loss of 10 W, implying that the thermal stability and uniformity of the cavity has been significantly improved. Through the synergistic control of four metal film resistors, a cooling rate of 0.06 K/min near 18 K is realized, and the cavity temperature gradient is reduced to 0.17 K/m, which effectively improves the RF performance of the cavity. The maximum Eacc of the cavity reaches 3.42 MV/m, and the Q0 is 1.1 × 109. An electromagnetic–thermal coupling simulation model for the superconducting cavity is established and is in good agreement with the experimental results. The simulation results show that the cavity with a Cu-spraying treatment and the thermal links of 5N Al can satisfy the Eacc of 10 MV/m under conduction cooling.

In the work the computer model of a cell of a system for generating fluxes of therapeutic beams of delayed neutrons, based on the use of delayed fission neutrons, was developed in the Geant 4 environment. The principle of such a neutron source is that when a powerful electron beam interacts with a combined tungsten target and a target containing fissile material, a fission reaction occurs; as a result of which neutrons are emitted. If we move a target activated in this way several tens of meters into a neutron flux generation system consisting of a heater, protection, collimator and reflector, we will obtain a compact neutron source for nuclear medicine. A significant advantage of such a neutron source is the absence of gamma background from the electron accelerator and the combined target, and a bulky protection system is not required. In the Geant 4 environment, the geometry of this cell was developed and a series of experiments were carried out with 107 neutrons. The QGSP BIC HP physical sheet was used. A study of neutron energy spectra showed that more than half of the neutrons whose fluxes are formed using such a cell of the formation system have an energy

Gelatin was doped with 1 %, 3 %, 5 % and 10 % cadmium sulfide nanoparticles in weight concentrations forming the gelatin‐cadmium sulfide nanocomposites and irradiated by various electron beam doses equals 50 kGy, 75 kGy, 100 kGy, and 150 kGy using 3 MeV – 3 mA electron accelerator. The applied alternating current electrical field frequency ranging from 70 Hz to 5 MHz is what caused the fluctuation in dielectric properties and alternating current electrical conductivity of these nanocomposites. The results showed that the films of 1 %, 3 %, 5 %, and 10 % for blank (nanocomposite film without electron beam irradiation) nanocomposites had the highest dielectric parameters (έ, ϵ′′, tan δ) at 0.5 kHz with values of (0.696, 0.0233, 0.034), (0.533, 0.0114, 0.0215), (0.402, 0.001196, 0.003), and (0.459, 0.00418, 0.0091), respectively. However, the lowest dielectric parameters were (0.645, 0.00618, 0.0066), (0.523, 0.00165, 0.0215), (0.417, 0.00035, 0.0008), and (0.455, 0.00066, 0.0015) at 5 MHz, respectively. The highest conductivity values for blank nanocomposites of 1 %, 3 %, 5 %, and 10 % were 1.79×10−4 S/m, 1.45×10−4 S/m, 1.16×10−4 S/m, 1.27×10−4 S/m at 5 MHz, and the lowest values were 1.92×10−8 S/m, 1.49×10−8 S/m, 1.13×10−8 S/m, 1.26×10−8 S/m at 0.5 kHz, respectively. For irradiated nanocomposites at 5 MHz, the dielectric constant order for 1 % was 100 kGy, 150 kGy, 50 kGy, and 75 kGy with values 0.63, 0.537, 0.532, and 0.523, respectively. For 10 % weight concentration, the order was 50 kGy, 100 kGy, 150 kGy, and 75 kGy with values 0.515, 0.477, 0.47, and 0.437, respectively. Otherwise the dielectric constant order for 3 % and 5 % was 100 kGy, 75 kGy, 150 kGy, and 50 kGy. The highest dielectric properties and conductivity values for blank and irradiated nanocomposites were observed at 100 kGy for 1 %, 3 %, and 5 %. [ABSTRACT FROM AUTHOR]

Molybdenum-99 (99Mo) is used for preparing Technetium-99 m (99mTc), which is the most widely used isotope in nuclear medicine. In this work, a study for 99Mo production based on a high-power electron accelerator has been performed as an alternative approach to produce 99mTc. In this study, Monte Carlo MCNPX2.6 code has been used to examine a novel idea of simultaneous hybrid production of 99Mo via both photoneutron and neutron capture reactions using an electron accelerator in heavy water tank. It is expected that this conceptual design including an arrangement of metallic plates of 100Mo and 98Mo produces total activity of 97.5 Ci at the end of 20-h continuous e-beam irradiation (30 MeV, 10 mA).

The bremsstrahlung is an important source term in the shielding design of the electron accelerator. In order to study the characteristics of the photon source term in the 90° direction and the influence of target radius and thickness on the bremsstrahlung in the 90° direction, the Monte Carlo program of MCNPX27 was used to calculate the radiation source term from the 15 MeV3 GeV electron beam incident on the iron target with different thicknesses and radii. The variation characteristics of radiation source items such as photon radiation dose rate and photon energy spectrum with target thickness and radius were obtained and comparatively analyzed. By comparing with the photon source term in the 0° direction and the energy deposition of cascade electron in the target, the main features of the photon source term in the 90° direction were obtained. Finally, the effects of beam power and beam intensity on radiation dose rates in the 90° and 0° directions were analyzed. The result shows that, due to the combined influence of electron energy deposition in the target and self-absorption of photons from the target, the radius and thickness of the target are expected as important factors which affect the photon source term in the 90° direction. The energy of the cascade electrons deposited in the target and the radiation dose rate in the 90° direction increases with the thickness. As the energy of the cascade electrons is completely deposited in the target, the radiation dose rate in the 90° direction will not change with the target thickness. The radiation dose rate in the 90° direction also increases with the target radius, but when the target radius is larger, the radiation dose rate in the 90° direction decreases due to the selfabsorption. Apart from that, the effect of incident electron energy on the photon source terms in the 90° direction and 0° direction is different. More than 99% of the photons in the 90° direction are below 10 MeV, and most of them are within 3 MeV. In the 90° direction, the photon energy spectrum shape has little relationship with the incident electron energy. However, the photon energy in the 0° direction can reach the incident electron energy, which is generally much larger than the photon energy in the 90° direction, and the shape of the energy spectrum is greatly affected by the incident electron. As a suggestion, the influence of the target size should be considered in the shielding design of the electron accelerator, and the design in the lateral shielding should be optimized according to the difference between the photon source term in the 90° direction and 0° direction.

The optical radiation in a gaseous medium upon the irradiation of a lithium layer with a fast electron beam of a 5 ns duration has been studied. The irradiation chamber was filled with argon, krypton, or xenon at a pressure of 10 kPa up to 60 kPa. The lines of lithium atoms appear in the emission spectrum at a lithium layer temperature of 650–680 K, and the intensity of these lines sharply increases with the increasing temperature of the lithium layer. The optical radiation arises from both the transitions of noble gas atoms and the transition of the lithium atom in a time of about 20–30 ns. The duration of the radiation pulses at half maximum at temperatures above 800 K was 60–100 ns at a wavelength of 610.4 nm and 140–220 ns at 670.8 nm in krypton and argon. The various mechanisms for the population of lithium levels during the radiation pulse are discussed. [ABSTRACT FROM AUTHOR]

Based on analytical description of isotope production by bremsstrahlung (X-ray) radiation, an algorithm is proposed for calculating the optimal dimensions of a cylindrical target of given mass positioned at a given distance from a bremsstrahlung converter to ensure the maximum yield of the isotope product. The expressions are derived for the total activity and its distribution along the target axis. A technique of γ-spectrometric measuring the activity of a thick production target is proposed. The novel approach is validated by the 100Mo(γ,n)99Mo reaction induced in a natural molybdenum target by mass in the range 10–100g with the X-ray photons at an end-point energy of 40 MeV. The analytical predictions are in good agreement with the results of Monte-Carlo simulations and experiment. • An analytical method has been proposed to calculate the optimal target dimensions at isotope production by X-rays. • A set of parameters has been established that determine the photonuclear yield of an isotope in a target. • An expression has been derived for the attenuation coefficient of induced linear activity of a cylindrical target. • A novel method for measuring the total gamma activity generated by bremsstrahlung in a thick target is proposed. [ABSTRACT FROM AUTHOR]

As the decay daughter of 99Mo, 99mTc is the most widely used radioisotope in the field of nuclear medicine. Recently, the major 99Mo production reactors in the world are facing problems such as unplanned maintenance, shutdown and decommission, resulting in the unstable supply of 99Mo. Therefore, many developed countries have been actively exploiting alternative technologies for 99Mo production. In this paper, various 99Mo-production technologies by particle accelerator instead of reactor were introduced, and the research progress of producing 99Mo based on electron accelerator was summarized at home and abroad. The accelerator performance index and the key technologies in the production process were discussed in detail, such as the design of irradiation device and target, separation of 99mTc, recovery of 100Mo and waste management. In addition, some suggestions were put forward for the basic and applied research of relevant technologies in China and the commercialization of 99Mo production by electron accelerator.

Ongoing energy measurement is one of the parameters such as: electron beam current, transporter speed, or scanning width, that must be recorded according to the conditions imposed in the accelerator validation procedure. Described measurement method based on the use of a secondary electron collecting electrode has been tested at the electron beam linear accelerator installation typically used for radiation sterilization. Data processing and presentation of the electron beam characteristics is based on the information obtained via dedicated pulse acquisition interface. The energy spectra parameters provide data for modeling and calculation of dose distribution for irradiation process optimization and also knowledge of accelerator RF alignment in case of service.

Monochromatic hard X-rays with high brightness are desired for medical applications including Auger therapy. One can generate such X-rays through laser-Compton scattering (LCS) by allowing photons from a compact laser system to interact with electrons accelerated by a compact electron accelerator. In this paper, after a brief description of laser-Compton X-ray sources, a scheme called crab crossing to enhance the X-ray intensity is proposed. The effect of crab crossing is evaluated, and we report our dedicated laser system for the crab crossing LCS research. The luminosity enhancement factor by crab crossing is evaluated. For the electron beam, a rf deflector will be used to generate a tilted electron beam. For the laser system, chirped pulsed amplification is adopted. Yb-doped optical fibers and a Yb:YAG thin-disk is used for the laser gain media. The luminosity enhancement factor by crab crossing is expected to be 3.8 when the crossing angle is 45 degrees. 10mJ pulse energy was achieved by thin-disk regenerative amplifier. The pulse duration after the pulse compressor was about 1.5 ps. We are going to demonstrate the LCS X-ray enhancement by crab crossing of electron beam and laser pulse. The expected enhancement factor is 3.8. We have successfully finished the laser development and the proof-of-principle experiment will be conducted soon. [ABSTRACT FROM AUTHOR]

Copyright of Nuclear Safety is the property of Nuclear & Radiation Safety Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Radiation treatment of food products carried out to increase their shelf life can result in chemical transformations initiated by free radicals. Volatile compounds (alcohols, aldehydes, ketones, etc.) formed, in particular, as a result of lipid oxidation, impair the organoleptic properties of products. Method of gas chromatography-mass spectrometry (GC-MS) makes it possible to identify the fact of food processing by detection of volatile marker compounds: in the case of meat products, the existing standard brings under regulation detection of 2-alkylcyclobutanones, however, the products with a reduced fat content, such as turkey and chicken, require an alternative marker. The results of GC-MS study revealed the dependence of microbiological parameters and the content of various volatile organic substances in chilled turkey meat on the dose of electron radiation. It is shown that the total amount of alcohols, ketones and aldehydes (11 compounds) decreases exponentially with an increase in the absorbed dose. An increase in the radiation dose leads to a higher content of carbonyl compounds (aldehydes and acetone), which results in a specific taste and smell of the irradiated products. At the same time, the acetone concentration increases linearly with the absorbed dose, which makes it possible to use acetone as a potential marker of the degree of irradiation of low-fat meat products. Irradiation in the "working" doses (0.5–1 kGy) significantly suppresses the pathogenic microflora and keeps the organoleptic properties of the product. [ABSTRACT FROM AUTHOR]

The radiation-induced emission (RIE) of Gd3+-doped sol–gel silica glass has been shown to have suitable properties for use in the dosimetry of beams of ionizing radiation in applications such as radiotherapy. Linear electron accelerators are commonly used as clinical radiotherapy beams, and in this paper, the RIE properties were investigated under electron irradiation. A monochromator setup was used to investigate the light properties in selected narrow wavelength regions, and a spectrometer setup was used to measure the optical emission spectra in various test configurations. The RIE output as a function of depth in acrylic was measured and compared with a reference dosimeter system for various electron energies, since the dose–depth measuring abilities of dosimeters in radiotherapy is of key interest. The intensity of the main radiation-induced luminescence (RIL) of the Gd3+-ions at 314 nm was found to well represent the dose as a function of depth, and was possible to separate from the Cherenkov light that was also induced in the measurement setup. After an initial suppression of the luminescence following the electron bunch, which is ascribed to a transient radiation-induced attenuation from self-trapped excitons (STEX), the 314 nm component was found to have a decay time of approximately 1.3 ms. An additional luminescence was also observed in the region 400 nm to 600 nm originating from the decay of the STEX centers, likely exhibiting an increasing luminescence with a dose history in the tested sample. [ABSTRACT FROM AUTHOR]

Industrial Electron Linacs have become popular tools for a multitude of radiation technology applications in the fields of material modification, pollution control as well as national security. Although thousands of accelerators are being regularly used, failure analysis of Industrial Electron Accelerators remains a sparsely researched topic and not much information is available in public. Being an economically viable option, industrial electron accelerators need to have a 24 × 7 reliable operation. Hence, it is necessary to understand the failure modes and their mitigation techniques, so that the operation of the accelerators is stable, consistent and safe. In this study, failure mode analysis and identification of degradation mechanisms in an industrial 10 MeV RF electron linac have been studied, with emphasis on the electron gun. Failure modes of the linac and its sub-systems have been investigated. Failure Mode and Effects Analysis and Fault Tree Analysis techniques have been examined for the electron gun. Bayesian Networks are used for modelling the performance of electron gun sub system, utilising the operational data of the RF linac. This approach has facilitated the evidential reasoning process to investigate most probable mode of failure and preventive measures have been recommended for mitigation of failure. [ABSTRACT FROM AUTHOR]

Fig is susceptible to lose fruit sensory quality due to its delicate skin and the natural bottom fruit pore. X-ray irradiation is an effective strategy for fruit preservation. This study investigated appearance and basic quality attributes of 'Siluhongyu' fig and evaluated the effects of X-ray on fig sugar metabolism and relative expression of genes. Results indicated that 'Siluhongyu' fig could be accepted by consumers with suitable overall dimension, soluble sugar, titratable acidity (TA), soluble protein, and dietary fiber contents. Sugar metabolism assay revealed that 3.0 kGy X-ray effectively inhibited the decline of glucose, fructose and sucrose contents. The starch degradation and the increase of amylase activity of figs were alleviated. In addition, the neutral invertase (NI), sucrose phosphate synthase (SPS), sucrose synthase (SS) and phosphofructokinase (PFK) activities in figs were activated by 3.0 kGy X-ray. About 22 % higher hexokinase (HK) activity was found in 3.0 kGy irradiated fruit than non-irradiated figs. Furthermore, 3.0 kGy X-ray upregulated gene expressions of NI, SS, HK, and PFK. The study proves that 3.0 kGy X-ray could be used as the feasible preservation means to regulate sugar metabolism and maintain quality of figs. • 3.0 kGy X-ray inhibited the decline of glucose, fructose and sucrose. • 3.0 kGy X-ray alleviated starch degradation and amylase activity. • 3.0 kGy X-ray activated sugar metabolism-related enzymes in figs. • 3.0 kGy X-ray upregulated gene expression of NI, SS, HK, and PFK. [ABSTRACT FROM AUTHOR]

A new irradiator design for large-scale dual-beam wastewater treatment in jet mode is proposed and analyzed. A combination of technical solutions previously used separately in the design of the ELV-12 and Electron-10 accelerators is considered. Accelerating tubes are used to produce bifurcated beams. Each half-beam is bent by 90° and directed towards the half-beam produced from the adjacent accelerating tube. The water jet is irradiated from both sides in the gap between the beam windows at a speed above 1 m s−1. The electron beams are oriented at an angle of 45–60° to the direction of the water jet. The angle causes a decrease in the useful thickness of the jet, but an increase in the depth dose in the cross section of the jet. Options for simultaneous irradiation of two and four water jets are considered. • One accelerator is capable of uniformly irradiating a high-speed water jet from both sides. • Bilateral irradiation is rational when the angle between the beam and the jet is 45–60°. • The angle determines a smaller useful jet thickness, but a higher transverse dose. • A configuration is proposed for large-scale irradiation of four jets simultaneously. [ABSTRACT FROM AUTHOR]

One of the most important tasks in the food industry is the search for alternative biochemical markers of radiation treatment in dietary, chilled meat products such as chicken and turkey. Major organic volatile chemicals found in meat products can be precisely identified using gas chromatography coupled with mass spectrometry. In the response to the needs of the food industry, our research team conducted a series of experiments involving the irradiation of chilled poultry meat using an electron accelerator. The experiments showed that the concentration of pure volatile organic compounds in saline solution dropped exponentially with an increase in the irradiation dose, which proves that these chemicals decomposed when exposed to ionizing radiation. However, when turkey meat was exposed to an electron beam with doses up to 1 kGy, the concentration of alcohols, aldehydes, and ketones peaked, only to decrease with an increase in the irradiation dose up to 2 kGy, and then went up slightly when the irradiation dose was within the range from 2 kGy to 10 kGy. To determine the reason behind the nonlinear dependencies of organic compound concentrations in turkey meat on the irradiation dose, we developed a mathematical model that acknowledges the presence of two opposing processes, those of decomposition and accumulation of organic compounds as a result of the decomposition of other compounds that can be found in turkey meat. [ABSTRACT FROM AUTHOR]

The main aim of this work is to investigate the dielectric and electrical properties of synthesized acrylic acid–gelatin blends of different acrylic acid weight concentrations with gelatin. An electron beam (EB) with different doses of 50–150 kGy irradiated the synthesized blend while it was also subjected to an applied electric field in the range of 70 Hz–5 MHz to determine the variation in the dielectric parameters and electrical conductivity. The lowest kHz gives the highest dielectric parameters and lowest AC electrical conductivity (σac) values for both the blank and EB-irradiated blends. The lowest dielectric parameters and σac values were at 0.4 g acrylic acid concentration, and the highest values were for the 0.2 g acrylic acid concentration. Comparing the different EB doses for each acrylic acid concentration, it was found that the order of the lowest dielectric constant, έ, was 0.579 for (0.2 g + 100 kGy) > 0.475 for (0.6 g + 50 kGy) > 0.412 for (1 g + 50 kGy) > 0.315 for (0.4 g + 100 kGy) at 0.5 kHz. However, the order of the highest σac was 1.71 × 10−4 S/m for (0.2 g + 150 kGy) > 1.39 × 10−4 S/m for (0.6 g + 75 kGy) > 1.08 × 10−4 S/m for (1 g + 75 kGy) > 8.56 × 10−5 S/m for (0.4 g + 150 kGy) at 5 MHz. A modified equation was deduced for the AC conductivity as a function of the frequency of the applied field and the concentration of acrylic acid mixed with gelatin at room temperature. [ABSTRACT FROM AUTHOR]

ABSTRACT Microbial contamination of the wort during the fermentation process causes significant losses in ethanol production worldwide and creates a dependence of the industry on chemicals and antibiotics to control contamination. Therefore, this study used electron beam (e-beam) to disinfect wort from sugarcane (Saccharum officinarum L.) molasses and investigate the bioethanol fermentation. Four treatments (T0 – T3) were carried out using ionizing doses of radiation through the electron accelerator: 0 (control), 10, 20, and 40 kGy. Total mesophiles, total bacteria, sucrose, glucose, fructose, phenolics, flavonoids, hydroxymethylfurfural (5-HMF), and Furfural were measured. An alcoholic fermentation assay was performed after the irradiation process. The irradiated treatments showed no inversion of sugars and formation of the inhibitory by-products flavonoids, furfural and 5-HMF, except for the phenolic compounds. The lower dose tested (10 kGy) reduced more than 99.9 % of the total mesophiles and more than 99.99 % of the total bacteria in the substrate. In the fermentation, the irradiated worts presented similar (p > 0.05) yields (92, 93, and 94 %) and ethanol productivity levels (0.89, 0.88, and 0.87 g L–1 h–1, for T1, T2, and T3 respectively). However, all treatments presented higher yields and productivity (p < 0.05) when compared to the control (88 % and 0.85 g L–1 h–1), highlighting the possible use of e-beam in wort fermentation at a lower dose (10 kGy). This allows reduction in losses caused by microbial contamination, besides increasing fermentation yield and productivity with lower energy consumption.

A mobile accelerator based on an ironless pulsed betatron is presented. The accelerator is designed for radiography of dynamic objects with large optical thicknesses and allows generation of up to three γ-pulses per acceleration cycle. Operation of the accelerator is described, and the results of test runs in the single-pulse mode are given. The estimated cutoff energy of the electron beam is 60 MeV at a storage capacity of 1.8 mF of the pulsed power supply system of the betatron electromagnet. The thickness of a transilluminated lead test object is 140 mm at a distance of 4 m from the radiation source (betatron target), the FWHM of the output γ-pulse is 120 ns, and the dimensions of the radiation source are 3 6 mm. Application of such accelerators in X-ray complexes will make it possible to optimize the scheme of gas-dynamic experiments, reduce the cost of the latter and, hence, increase the efficiency of research. [ABSTRACT FROM AUTHOR]

The optical radiation in a gaseous medium upon the irradiation of a lithium layer with a fast electron beam of a 5 ns duration has been studied. The irradiation chamber was filled with argon, krypton, or xenon at a pressure of 10 kPa up to 60 kPa. The lines of lithium atoms appear in the emission spectrum at a lithium layer temperature of 650–680 K, and the intensity of these lines sharply increases with the increasing temperature of the lithium layer. The optical radiation arises from both the transitions of noble gas atoms and the transition of the lithium atom in a time of about 20–30 ns. The duration of the radiation pulses at half maximum at temperatures above 800 K was 60–100 ns at a wavelength of 610.4 nm and 140–220 ns at 670.8 nm in krypton and argon. The various mechanisms for the population of lithium levels during the radiation pulse are discussed.

Ongoing energy measurement is one of the parameters such as: electron beam current, transporter speed, or scanning width, that must be recorded according to the conditions imposed in the accelerator validation procedure. Described measurement method based on the use of a secondary electron collecting electrode has been tested at the electron beam linear accelerator installation typically used for radiation sterilization. Data processing and presentation of the electron beam characteristics is based on the information obtained via dedicated pulse acquisition interface. The energy spectra parameters provide data for modeling and calculation of dose distribution for irradiation process optimization and also knowledge of accelerator RF alignment in case of service. [ABSTRACT FROM AUTHOR]

Background: The availability of linear accelerators (linac) for research purposes is often limited and therefore alternative radiation sources are needed to conduct radiobiological research. The National Centre for Radiation Research in Poland recently developed an intraoperative mobile linac that enables electron irradiation at energies ranging from 4 to 12 MeV and dose rates of 5 or 10 Gy/min. The present study was conducted to evaluate the electron beam parameters of this intraoperative linac and to verify the set-up to evaluate out-of-field doses in a water phantom, which were determined through dosimetric and biological response measurements. Materials and methods: The distribution of radiation doses along and across the radiation beam were measured in a water phantom using a semiconductor detector and absolute doses using an ionisation chamber. Two luminal breast cancer cell lines (T-47D and HER2 positive SK-BR-3) were placed in the phantom to study radiation response at doses ranging from 2 to 10 Gy. Cell response was measured by clonogenic assays. Results and Conclusion: The electron beam properties, including depth doses and profiles, were within expected range for the stated energies. These results confirm the viability of this device and set-up as a source of megavoltage electrons to evaluate the radiobiological response of tumour cells. [ABSTRACT FROM AUTHOR]

At the ELBE Center for High-Power Radiation Sources, electrons are accelerated to an energy of up to 40 MeV in a superconducting linear accelerator that is operated in continuous wave (CW) mode. The acceleration is achieved using superconducting radio frequency (RF) cavities, which are driven by an analog low-level RF (aLLRF) system and solid-state-based RF amplifiers. The analog aLLRF system was transformed to a digital system based on the MicroTCA standard. It is in user operation since 2020. Here, the new digital system and its integration in the ELBE control system are described. Furthermore, the system is characterized by noise measurements and shows rms field stability of the digital LLRF (dLLRF) system of 0.01° in phase and 0.005% in amplitude. In addition, an algorithm for compensating long-term drifts is presented and characterized. [ABSTRACT FROM AUTHOR]

Accurate measurements of photonuclear reaction cross sections are crucial for a number of applications, including radiation shielding design, absorbed dose calculations, reactor physics and engineering, nuclear safeguard and inspection, astrophysics, and nuclear medicine. Primarily motivated by the study of the production of selected radionuclides with high-energy photon beams (mainly 225 Ac, 47 Sc, and 67 Cu), we have established a methodology for the measurement of photonuclear reaction cross sections with the microtron accelerator available at the Swiss Federal Institute of Metrology (METAS). The proposed methodology is based on the measurement of the produced activity with a High Purity Germanium (HPGe) spectrometer and on the knowledge of the photon fluence spectrum through Monte Carlo simulations. The data analysis is performed by applying a Bayesian fitting procedure to the experimental data and by assuming a functional trend of the cross section, in our case a Breit-Wigner function. We validated the entire methodology by measuring a well-established photonuclear cross section, namely the 197 Au(γ , n) 196 Au reaction. The results are consistent with those reported in the literature. • Establish Bayesian fitting methodology for cross section measurement of photonuclear reactions. • Validation of the methodology using the Au-197(g, n)Au-196 reaction. • Photonuclear production of Au-196 using an electron accelerator. [ABSTRACT FROM AUTHOR]

In this work, the TiO2@TixCyOz nanocomposite was obtained by adding a buffer gas to the initial mixture of reagents by the pulsed plasma-chemical method. Argon was used as a buffer gas. Pulsed plasma-chemical synthesis was realized using a TEA-500 electron accelerator. The physicochemical properties of the obtained TiO2@TixCyOz nanocomposites (morphology, average particle size, elemental, and phase composition) were studied. It was shown that by changing the buffer gas concentration, it was possible to control the phase composition, particle size, and shell thickness of TiO2@TixCyOz nanocomposites. The values of the band gap were calculated for the synthesized TiO2@TixCyOz nanocomposites. The photocatalytic and adsorption properties of TiO2@TixCyOz nanocomposites were studied. [ABSTRACT FROM AUTHOR]

The study presents analysis of mass radiative energy losses (RL) incurred by relativistic electrons in different materials commonly used in semiconductor electronics. We have specifically focused on accounting for the processes of 'internal' ionization, resulting in the production of electron-hole pairs in semiconductors and dielectrics. We have established that accounting for these processes is the only method offering consistent explanations on the values of mass RLs observed experimentally. The analysis performed should allow to make more detailed predictions for the performance of semiconductor devices in real conditions, particularly, in space.

• Photofission is a promising technique for nuclear waste package characterization. • 9 MeV linear accelerator parameters and target materials impact the assay performance. • Monte Carlo simulations are conducted in PHITS and MCNP6 codes and compared. • Optimization of the photon flux and reduction of neutron background are conducted. Photofission-based active non-destructive assay is a promising technique for nuclear waste characterization. The latter is challenging due to the presence of actinides, fission products and non-homogeneous matrix. This paper presents an optimization study of a 9 MeV linear electron accelerator used as a source of Bremsstrahlung photons for such photofission applications. The primary focus is made on qualitative and quantitative assessment of the Bremsstrahlung flux, timing characteristics and reduction of background neutrons. Assessment is conducted using Monte Carlo simulations in particle transport codes PHITS and MCNP6 with an objective to compare the simulation results. Our results demonstrate a good agreement between the simulation results of both codes. However, for an effective application of the photofission technique for nuclear waste assay, a careful selection of the target material and introduction of parasitic neutron suppression techniques are necessary. Analysis routines and simulation procedures are described in detail and results are presented. [ABSTRACT FROM AUTHOR]

Currently available industrial electron accelerators and radiation-chemical reaction vessels designed for them make it possible to irradiate no more than 20 000 m3 of water per day, which is many times less than practical needs. At the same time, there are technical prerequisites for the development of more powerful accelerators suitable for large-scale water treatment. Interest in the electron-beam water treatment is rapidly increasing in light of the acute problem of neutralizing biologically hazardous impurities. Various designs of accelerators and reaction vessels used for a multiple increase in the productivity of the electron beam purification of water are considered. [ABSTRACT FROM AUTHOR]

Insulated core transformer (ICT) electron accelerator offers many advantages including high efficiency of energy conversion, high-power output, low cost, and high reliability. It is a superior type of E-beam systems for the radiation processing in the low energy region (<1MeV). The ICT power supply is the core component of the electron accelerator. The structure of the ICT cores is segmented, and it results in large magnetic flux leakage at the gaps between the cores. Therefore, the output voltages of different disks are non-uniform, which highly affected the performance of the ICT power supply. In order to reduce the non-uniformity caused by the magnetic flux leakage, a hybrid compensation method with optimizing the number of turns in secondary windings and adding dummy primary windings is presented in this paper. The compensation scheme is designed for an 800kV/50mA ICT power supply. The result shows the consistent output high voltage of disks is achieved and the non-uniformity is ≤ 6.5% from no-load to full-load when the output high voltage is 800kV. This design effectively improves the uniformity of the electrical field distribution, increases the utilization of the rectifier components and reduces the size of the power supply. [ABSTRACT FROM AUTHOR]