Search

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

Radiation-induced emission of doped sol-gel silica glass samples was investigated under a pulsed 20-MeV electron beam. The studied samples were drawn rods doped with cerium, copper, or gadolinium ions, which were connected to multimode pure-silica core fibers to transport the induced luminescence from the irradiation area to a signal readout system. The luminescence pulses in the samples induced by the electron bunches were studied as a function of deposited dose per electron bunch. All the investigated samples were found to have a linear response in terms of luminescence as a function of electron bunch sizes between 10−5 Gy/bunch and 1.5×10−2 Gy/bunch. The presented results show that these types of doped silica rods can be used for monitoring a pulsed electron beam, as well as to evaluate the dose deposited by the individual electron bunches. The electron accelerator used in the experiment was a medical type used for radiation therapy treatments, and these silica rod samples show high potential for dosimetry in radiotherapy contexts.

Cherenkov radiation is generated when relativistic charged particles move in a medium with refractive index larger than unity. Although, the refractive index is generally smaller than unity in X-ray region, in the vicinity of atomic absorption edges, the refractive index may exceed unity and Cherenkov radiation can be generated in soft X-ray region with a narrow band width. In this paper, the spectral-angular distribution of X-ray Cherenkov Radiation (XCR) and its properties are analyzed. It is shown that, by using electron accelerators which can produce 10 MeV electrons, with average current density 20 mA/mm2, and choosing different µm-thick foils, one can produce soft X-ray Cherenkov radiation source with intensity about 10-4 ph/el, and X-ray photon energy from 50 eV up to 1 keV. Some unique properties of XCR, such as narrow band width and high brightness, make XCR a novel soft X-ray source for applications in soft X-ray microscopy, photoelectron spectroscopy, analysis of trace elements and other research areas.

Electron curtain accelerator is a type of low-energy electron accelerator, which plays an important role in many different industries such as printing, coating and packing to promote product quality, while reducing volatile organic compounds for protecting global environment. Electron emitter is one of the main components of this type of accelerators. Multi-filament cathodes and grid structures within filament housing have been designed carefully to generate uniform broad beam distribution. Compared to single filament cathode, multi-filament cathodes are more preferred in width expansion and beam uniformity. Distortion of linear filament due to thermal expansion is one of the major problems in this type of electron source. The aim of this study is to design and fabricate an appropriate mechanical system to maintain the filament in its initial shape and position when heating. In addition, dependence of emitted electrons on anode voltage (at constant cathode temperature), as well as dependence of emitted electrons on filament current (at constant anode voltage) have been experimentally investigated.

Background and aim: Today, electron accelerators are taken into consideration as photoneutron sources. Therefore, for maximum production of epithermal neutron flux, designing a photoneutron target is of significant importance. In this paper, the effect of thickness and geometric shape of a photoneutron target on neutron output were investigated. Methods: In this study, a pencil photon source with 13, 15, 18, 20 and 25 MeV energies and a diameter of 2 mm was investigated using Monte Carlo simulation method using MCNP code. To optimize the design of the photoneutron target, the tungsten target with various geometries and thicknesses was investigated. Results: The maximum neutron flux produced for all target geometries and thicknesses occurred at neutron energy peak of around 0.46 MeV. As the thickness increased to 2 cm, neutron flux increased and then a decreasing trend was observed. For various geometrical shapes, the determining factor in photoneutron output was the effective target thickness in the photon interaction path that increased by the increase in the area of interaction. Another factor was the angle of the photon's incidence with the target surface that resulted in a significant decrease in photoneutron output in cone-shaped targets Conclusion: Three factors including the total neutron flux, neutrons energy spectrum, and convergence of neutrons plays an important role in the selection of geometry and shape of the target that should be investigated considering beam shaping assembly (BSA) shape

The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose calculations. Two shielding materials, heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary less than 5.0e-03 mSv/h during operation. The shield configuration and parameters of the accelerator building were determined and are presented in this paper.

In this paper, a high power tetrode tube (TH781-200kW, cw) modulator is designed and implemented. This modulator is used for a part of RF system of the first Iranian high power electron accelerator project with similar structure to Rhodotron accelerator. Regarding to the level of sensitive and importance of TH781 tube the modulator system designed with high accuracy. So beside of power supplies design the control circuits for protection of the tube have been considered. The results of test and operation of this system that have been constructed in Iran for fist time is very satisfactory

Electron accelerators use electric and magnetic fields to accelerate and control charged particles to the close proximity of the speed of light. The results of the experimental test performed on the Yazd Rhodotron cavity cooling system as well as the relevant numerical analysis carried out by the ANSYS 12 code are presented. It was found that the numerical prediction for the cavity wall temperature under normal operating condition was in reasonable agreement with the corresponding experimental result. In addition, due to the blockage effect of the cooling channels, the cavity wall temperature was higher than normal operating conditions.