Low Energy Electron Accelerator Research Articles

World experience in the application of low-energy electron irradiation in agriculture

According to the long-term observations of the FAO, losses of plant-based agricultural products are estimated to be between 10 and 30 %. The main causes of these losses are plant pathogens, spoilage microorganisms, and insect pests. The study discusses the problems of ensuring phytosanitary safety of agricultural products and proposes the use of radiation technology instead of chemical treatment. Radiation technology has a long history of research and application, spanning over 75 years. The most extensive and detailed data on the application of this technology have been obtained for gamma installations, which use natural radioactive isotopes. Lowenergy (less than 300 keV) electron accelerators were invented relatively recently, so the question of their use in agriculture is relevant. Treatment with low-energy electron radiation combines all the advantages of radiation treatment of food and agricultural products with gamma radiation, and at the same time, significantly reduces the risk of damage to biological structures inside the irradiated object due to the low penetrating power of the radiation. This study notes that low-energy electron accelerators can be successfully used to combat plant infectious diseases, reducing the amount of plant pathogens on seeds, without affecting their growth parameters. The use of low-energy electron irradiation to prevent microbiological spoilage is also discussed. The nutritional qualities of irradiated products are not significantly altered. The method of radiation disinfestation (control of insect pests) using low-energy electron radiation has also proven to be effective. However, it should be noted that additional research is necessary to determine the optimal doses of low-energy radiation for each type of product and to ensure safety for human health and the environment. Generally, the use of radiation technology in agriculture has great potential and can become an effective means of improving productivity and food safety. This method of food processing has been recognized as safe for human health by several authoritative international organizations, including the UN (FAO), WHO, IAEA, and others.

Electron beam irradiation-induced co-grafting and degradation of cotton cellulose with ionic liquid

We developed a cellulose upgrading method based on electron beam processing technology by using a carbon-carbon double bond-containing ionic liquid as an auxiliary reagent. The irradiation of cellulose was implemented by a 10 MeV high-energy electron accelerator or a 200 keV low-energy electron accelerator. The established method enabled grafting of the ionic liquid onto cellulose while triggering an irradiation degradation of cotton cellulose. By employing irradiation co-grafting degradation with a high-energy electron accelerator in the dose range of 30–40 kGy, highly uniform cotton cellulose with a high degree of polymerization (DP) of 500 and low degree of polymerization deviation (DPD) was obtained. By using a low-energy accelerator in the dose range of 4–6 kGy, cotton cellulose with a high DP of 1000 and low DPD was prepared. This method to upgrade cellulose has advantages of simple operation, short reaction time, and minimal amount of chemical reagents. It opened an avenue to access high quality of cellulose that cannot be attained with other method.

Study the dose profile of low energy electron accelerator

This paper describes dose mapping method for Low Energy Electron Accelerator (LEEA). This locally designed LEEA with the former energy of 140 keV will be upgraded to 300 keV. In the setup, the electron beam is energized by the electric field with high voltage power supply, scanning and passing through the titanium foil, to irradiate the sample. The dose profile by the energetic beam mapping results have been obtained by using Cellulose Triacetate (CTA) dosimeter.

О возможности внедрения в агропромышленный комплекс низкоэнергетических (до 300 кэВ) электронных ускорителей (обзор)

An important place in the system of measures to ensure the phytosanitary safety of agricultural produce is traditionally given to chemicals. However, due to negative effects of the chemicals on the environment, new more effective and safe technologies were needed. Feasibility of the use of radiation technologies to improve food safety and agricultural quality has been studied for more than 75 years. Recently radiation-based technologies have become increasingly important in agricultural produce processing to preserve food spoilage during storage. Currently the use of electron beams with energy below 300 keV generated by electron accelerators is increasingly grown in agriculture. The key feature of electron beams is their ability to produce disinfectant ef-fect on irradiated object due to low electrons permeability. It prevents the characteristic radiation-chemical reactions and damage to the structure in the internal volume of the biological specie Such objects are seeds of agricultural plants susceptible to infectious diseases caused by phyto-pathogens. The study aims at the evaluation of the possibility to use low-energy (below 300 keV) electron accelerators in the agro-industrial complex. The paper describes the device and the principle of operation of the state-of-the-art low-energy electron accelerators, as well as their ap-plication in the agricultural sector. The paper considers the effects of low-energy electron irradia-tion of agricultural products on seed phytopathogens and pests. From the analysis of feasibility of use of the low-energy electron accelerators for radiation-induced disinfection and disinsection it becomes evident that irradiation of the crop with low-energy electrons is effective approach to minimize adverse effects of phytopathogens and to prevent destruction of irradiated biological objects. Electron-beam irradiation minimally effects on the nutritional quality of food products.

Широкоапертурные низкоэнергетичные ускорители электронов АО «НИИЭФА» на основе высоковольтного тлеющего разряда

Широкоапертурные низкоэнергетичные ускорители электронов АО «НИИЭФА» на основе высоковольтного тлеющего разряда

Electron range after titanium foil window from low energy electron accelerator

Currently, the low energy electron accelerator machine in Malaysian Nuclear Agency is at the commissioning stage. Various parameters are tested and studied. One of the parameters is the electron range in the air through titanium foil window. This parameter is important for the process of sample irradiation. There are two methods to determine this parameter. The first is through manual calculations and second is through Monte Carlo code simulations using PHITS. This paper describes the results of both methods and attempts to make comparisons between them.

Development of the scanning power supply for 300 keV electron accelerator

This paper describes the development and study of the scanning power supply. This locally designed low energy electron accelerator with the former energy of 140 keV will be upgraded to 300 keV. As the setup, scanning power supply is required to excite the scanning coils and deflect the energetic electron beam across a titanium foil window in horizontal and vertical direction respectively. The excitation current of the scanning coils is determined by the energy of the electron beam and the deflected length. Therefore, the scanning power supply must be functioning automatically and continuously to ensure the uniform dose distribution and unavoidable heat issue. As the result, the scanning power supply using the combination of signal generator and power amplifier has been developed and functioning as expected.

Comparison of Large-Area Low-Energy Electron Accelerators Based on a High-Voltage Glow Discharge with Accelerators Based on Longitudinal Filaments

Abstract—A wide-aperture low-energy electron accelerator based on a high-voltage glow discharge (HVGD) is considered in comparison with accelerators based on a number of longitudinal filaments. The basic design features and advantages of HVGD-based accelerators are presented. These studies showed that it is possible to obtain high values of the density of the electron beam current extracted from the foil (56 µA/cm2) and rather high values of the beam extraction efficiency (35%) in comparison with the previously attained results. The obtained characteristics are comparable with the parameters of the accelerators based on a number of longitudinal filaments. The ability of the accelerator to operate with HVGD is demonstrated both in continuous and pulse–periodic modes without a change in its design. Various ion–electron optical systems of HVGD accelerators have been studied and the advantages of slit-type systems are shown.

Study on the filament power supply of the 300 keV electron accelerator

This paper describes the study and development of the filament power supply. This locally designed low energy electron accelerator with the present energy of 140 keV will be upgraded to 300 keV. The filaments are used to heating-up and produce the electron. The produced electron will be accelerated through a potential different by a DC High Voltage Power Supply (DCHVPS). Whereby this filament power supply is connected with the DCHVPS, therefore the isolation of high voltage is required. For such purpose, the specifications and the isolation mechanisms of the filament power supply have been identified. As the result, the filament power supply by using an air core transformer has been selected and developed with the required heating power.

Vacuum pumping system for the multi-aperture low-energy continuously-operated electron accelerator with a high-density beam current

The vacuum pumping system for an electron accelerator has been developed on the basis of arc sources of getter film and ion getter pumps. The contradictory problem has been solved, that is, it was necessary to provide, on the one hand, the maximum efficiency of the pumping speed and, on the other, a minimal return flow of the metallic plasma shunting the accelerating gap. The program and procedure have been elaborated for the numerical simulation of getter pumping taking into account the mass-transfer non-uniformity. The experimentally obtained vacuum characteristics of the developed pumping system for the accelerator are presented.

Study on the window cooling system of 300 keV Electron Accelerator

This paper describes the method used to identify the parameters required for the window cooling system. This locally designed low energy electron accelerator with the present energy of 140 keV will be upgraded to 300 keV. The heat will be increased due to the increment of the beam energy; therefore an appropriate cooling system is required to prevent the breaking of the few µmm titanium window. The broken window will disrupt the beam transportation inside the vacuum environment of the accelerating tube and also the high voltage will be breakdown if the vacuum environment couldn’t be sustained. Therefore, a desired air cooling system to cool down the 9 kwatt (30 mA, 300 keV) beam power has been designed. As the result, the window cooling system with the required pressure based on the beam powers have been calculated and identified.

A scintillator detector for beam tuning of low-energy single electron accelerator

Nine scintillator detectors were developed for beam tuning of low-energy single electron accelerator instead of the picoammeter and Faraday cup, both of which will be insensitive to the weak-current beam lower than picoampere. The detectors are based on plastic scintillator and photomultiplier tube (PMT) and the beam is 100 Hz pulsed electrons in the energy range of 0.1 to 50 MeV. The beam flux was tuned from about 10 $$^7$$ to quasi-single electron for each bunch according to the measurement results of these detectors installed along the beam pipe and after slits. In order to determine the number of electrons in a bunch, the gains of each PMT were finely calibrated, and the energy response of each detector was calibrated with $$^{207}$$ Bi radioactive source. Moreover, the deposited energy in the plastic scintillator, the electron detection efficiency and light collection efficiency, as a function of electron incident energy, were also simulated in detail by Geant4. Nine detectors worked well at a gain of $$0.6\times 10^6$$ after installation in the beam pipe, and the number of electrons in a bunch could be measured at each detector position. The single electron peak was seen when the beam reached the final detector. The commissioning result shows that the beam was tuned to quasi-single electron level successfully and the scintillator detector is an effective method to measure the weak-current beam lower than picoampere.

Fabrication and characterization of silver nanoparticles by using a low energy electron accelerator with a flow reactor

The mass production of silver nanoparticles by using a low-energy-electron accelerator with a flow reactor was carried out. The flux of the silver precursor was 55 ml/min, and the electron beam’s conditions were a fixed beam energy of 0.2 MeV and a beam current of 1 mA. The irradiation area and time were 8 cm × 2 cm and 9.7 seconds, respectively. The yield of silver nanoparticles was about 26.67% in a flow reactor. On the other hand, the yield of silver nanoparticles was around 9% in a batch reactor. Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) showed a synthesis of pure silver nano particles whose surfaces were not oxidized. The size distribution of the fabricated silver nanoparticles was very uniform with sizes from 40 to 50 nm, and the sheet resistance measured using a four-point probe was lower than 3.5 mΩ/sq.

Application of aluminum and titanium foils in low-energy wide-aperture electron accelerators

We have reported on the results of theoretical and experimental investigations of characteristics of aluminum and titanium foils used in devices to extract electron beams from wide-aperture low-energy accelerators with a high current density. The mechanical properties of foils at different temperatures and the electron beam transmission and absorption coefficients have been compared. The results of analyzing the dependences of the efficiency of the electron beam extraction from accelerators on the type of the electron–optical system, material, and thickness of the foil for various sizes of extraction windows and the same type of the slot support grids have been presented. We have proposed an analytic model for calculating the temperature of the foil in the unit cell of the support grid. The electron transmittance and absorbance, as well as the temperature regimes of the foils, have been calculated using different methods.

Betavoltaic Performance of Radiation-Hardened High-Efficiency Si Space Solar Cells

Long-lived and high-energy-density betavoltaics have a great potential as power supplies for remote and hostile environmental conditions, where volume power density and/or power lifetime are very important considerations. In this paper, we provide new results to aid in the design and optimization of betavoltaics made with Si space solar cells and beta sources. The new results were obtained by using a customized low-energy electron accelerator to characterize the radiation-hardened high-efficiency Si space solar cells while varying the electron beam energy and electron beam current density, i.e., electron beam flux. The betavoltaic conversion efficiency of Si space solar cells increases until 60 keV and then decreases with the increasing electron beam energy. The maximum efficiency (6%) obtained at the electron beam energy of 60 keV suggests that Pm-147 would be a good beta source to make high-efficiency nuclear batteries. The radiation ionization energy is ~ 3.90 eV per electron-hole pair for Si space solar cells. Some radiation damage-induced performance degradation was also observed when the Si space solar cells were exposed to the bombardment of 62-keV electrons with fluence up to 4.92 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">18</sup> betas/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which is equivalent to the radiation from a semi-infinite Pm-147 layer for ~ 2.26 years. The results in this paper suggest that beta-particle entrance window, betavoltaic cells' configuration structure, and device properties such as charge carriers' diffusion length are very important factors to be engineered to improve the conversion efficiency for practical betavoltaics.

Investigate the nonuniformity of low-energy electron beam with large cross-sections

Over the past decades, low-energy electron accelerators have been used worldwide for surface curing and sterilization. The beam nonuniformity is an important parameter of the low-energy electron beam with large cross-sections. A simple and accurate measurement system of nonuniformity for the low-energy electron beam with large cross-sections was developed. The main concept consists in the measurement of nonuniformity, which is realized by using a linear actuator to drive two scanning wires through the beam's cross-sections at a fixed speed. The beam distribution can be obtained by sending/collecting the current signals to/from the Data Acquisition (DAQ) software on a laptop by a USB DAQ card. This device is very convenient for the performance testing of a new accelerator at the manufacturer's site. The distribution of the homemade low voltage electron accelerator EBS-300-50 was measured and evaluated.

Theoretical and experimental study of electron-optical systems in low-energy wide-aperture electron accelerators

A large-area electron accelerator based on filament cathodes that operates in a continuous mode is described. The results of calculations of electron-optical systems of triode- and tetrode-type accelerators in accordance with the proposed engineering approach are considered, and experimental and calculated parameters of the accelerator are compared.

Development of high intensity source of thermal positrons APosS (Argonne Positron Source)

We present an update on the positron-facility development at Argonne National Laboratory. We will discuss advantages of using low-energy electron accelerator, present our latest results on slow positron production simulations, and plans for further development of the facility. We have installed a new converter/moderator assembly that is appropriate for our electron energy that allows increasing the yield about an order of magnitude. We have simulated the relative yields of thermalized positrons as a function of incident positron energy on the moderator. We use these data to calculate positron yields that we compare with our experimental data as well as with available literature data. We will discuss the new design of the next generation positron front end utilization of reflection moderator geometry. We also will discuss planned accelerator upgrades and their impact on APosS.

Trends for Electron Beam Accelerator Applications in Industry

Electron beam (EB) accelerators are major pieces of industrial equipment used for many commercial radiation processing applications. The industrial use of EB accelerators has a history of more than 50 years and is still growing in terms of both its economic scale and new applications. Major applications involve the modification of polymeric materials to create value-added products, such as heat-resistant wires, heat-shrinkable sheets, automobile tires, foamed plastics, battery separators and hydrogel wound dressing. The surface curing of coatings and printing inks is a growing application for low energy electron accelerators, resulting in an environmentally friendly and an energy-saving process. Recently there has been the acceptance of the use of EB accelerators in lieu of the radioactive isotope cobalt-60 as a source for sterilizing disposable medical products. Environmental protection by the use of EB accelerators is a new and important field of application. A commercial plant for the cleaning flue gases from a coal-burning power plant is in operation in Poland, employing high power EB accelerators. In Korea, a commercial plant uses EB to clean waste water from a dye factory.

Development of the Positron Facility at the Argonne National Laboratory’s 20 MeV Linac

We present an update on positron-facility development at Argonne National Laboratory. We will discuss advantages of using low energy electron accelerator, present our latest results on slow positron production simulations, and plans for further development of the facility. We have installed a new converter/moderator assembly that is appropriate for our electron energy and that allows increasing the yield about an order of magnitude. We have obtained a Penning trap and buncher from LLNL that we plan to install. We have simulated the relative yields of thermalized positrons as a function of incident positron energy on the moderator. We use these data to calculate positron yields that we compare with our experimental data as well as with available literature data. We will discuss the new design of the next generation positron front end utilizing reflection moderation geometry.