Industrial Electron Accelerators Research Articles

Study and design of an energy monitoring device for an industrial electron accelerator using Monte Carlo simulation

Beam energy is one of the primary parameters of an electron irradiation accelerator, which affects the internal dose distribution of irradiated items. This study designs an energy monitoring device that can track the energy variation of an industrial electron accelerator in the range of 1.2–2.0 MeV. By using Monte Carlo simulation, the construction and parameters of the energy monitoring device were designed and optimized. An experimental measurement platform was designed and built according to the needs of the measurement environment. The experiments were performed under an industrially irradiation Dynamitron accelerator. The test results demonstrate that the designed energy monitoring device is capable of continuously monitoring beam energy and meeting the measurement requirement. This study identified a new correlation between the energy ratio and beam energy, which provides a reference to guide the design and application of future energy monitoring devices.

A Real-Time Electron Beam Uniformity Measurement System for Irradiation Electron Accelerator: Design and Test

Electron accelerators are becoming increasingly significant in the irradiation industry. Beam uniformity is a critical accelerator parameter that influences the quality of irradiation processing technology. As a result, precise measurement of beam uniformity is necessary. In actual processing and production, the accelerator often needs to operate continuously under different beam current conditions. The aim of this work is to offer a new measurement system that can determine the beam uniformity of electron accelerators in real-time under various beam currents. The measurement system is implemented based on the intercept measurement method. The electron collection device is designed using the Monte Carlo simulation code FLUKA, and the electron beam collection efficiency is effectively calculated. To realize the measurement under large beam power conditions, the thermal–mechanical analysis of the collection device was carried out using the finite element simulation software ANSYS, and a cooling device was designed. A measurement device platform was created using the design parameters and tested under an industrial irradiation electron accelerator with a beam energy of 1.2 MeV and beam current of 0–18 mA. The test results showed that the device could measure the beam scanning distribution in real-time under different beam current conditions. In addition, the uniformity measurement results showed that under the same beam energy condition, as the beam current increases, the uniformity gradually decreases and tends to be stable, but the difference between the beam current at the two ends and the middle position increases. The effective design and successful test of the device make it possible to use the device to measure the scanning uniformity of electron accelerators in the future, and the measurement results will provide an essential reference value in the production and application of accelerators.

New beam delivery system design for industrial electron accelerator at Nuclear Science and Technology Research Institute, Iran

The output beams generated by industrial electron accelerators should be swept over the product. It is necessary to determine the exact scan length in order to ensure that an efficient dose reaches the product and to avoid the loss of the beam in contact with the sides of the product. Another challenge associated with scanning beams is the non-uniformity of the dose across the entire product during irradiation. In this study, the use of beam correction magnets is proposed for correcting products that receive a non-uniform dose. These magnets correct beams that are not swept in parallel. In addition, we simulated the dose received by the products in two non-uniform and uniform modes (modified by beam correction magnets) using the Monte Carlo method, and compared the results to assess the importance of using an appropriate irradiation system. Among the proposed magnets, a modified sector magnet is recommended for correcting the beam path and reducing the side effect. Using this magnet for a long horn does not require a cooling system, but using it for a short horn increases the need for a water-cooling system.

Enhancement in structural, optical and morphological properties of sprayed In2O3 thin films induced by low energy electron beam irradiation

In2O3 thin films have been synthesized on glass substrates by spray pyrolysis then irradiated by electron beam (EB) at low energy of 0.8 MeV for three fluencies 4.1016, 35.1016 and 42.1016 electron/cm2. EB irradiation was performed by an industrial electron accelerator owned to COFICAB Company. Structural, optical, photoluminescence and morphological properties of In2O3 thin films have been investigated before and after EB irradiation by X-ray diffraction, spectrophotometer, SEM and fluorescence spectrometer. After EB irradiation at 4.1016 electron/cm2, the preferred orientation of In2O3 thin film was moved from (222) to (400) with a simultaneous improvement in grain size. For EB fluency of 35.1016 electron/cm2, In2O3 thin film has been strangely transformed from polycrystalline phase to a single crystal structure. After irradiation at 42.1016 electron/cm2 fluency, In2O3 thin film became amorphous. A clear enhancement in optical transmission has been observed after irradiation with a slight variation in band gap energy. Surface morphology of the irradiated In2O3 thin films has been transformed from rough to continuous, uniform and smooth surface. This study have shown that EB irradiation can be considered as a useful mean for enhancement of In2O3 thin films physical properties and suggest its use for the space optoelectronic applications.

Features and Ways to Upgrade Electron-Beam Wastewater Treatment

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.

Using Low-Energy Electrons for the Radiation Treatment of Chilled Trout

Chilled minced trout has been treated by 1-MeV electron-beam irradiation using the UELR-1-25-T-001 industrial electron accelerator. The results of the effect of exposure with doses of 0.24, 0.48, 0.96, 2.8, and 5.6 kGy on the viability of microorganisms in minced fish are presented. It is experimentally shown that electron radiation generated by the accelerator in doses of 0.24–5.6 kGy reduces the microbial content in minced trout when compared with unirradiated samples 15 days after irradiation and controls the microbial content of chilled fish products for 2 weeks after radiation treatment.

CALIBRATION OF A SYSTEM FOR ON-LINE MONITORING OF ELECTRON ENERGY AND ABSORBED DOSE AT AN INDUSTRIAL ACCELERATOR LU-10

Particle beam energy and absorbed dose are critical parameters of product processing at industrial electron accelerators. For on-line monitoring of those parameters, a method based on measuring of distribution of the charge induced by irradiation in a wide-aperture stack-monitor, positioned behind an irradiated object, has been developed. A brief review of a control system for monitoring of the processing parameters created with the use of the EPICS package as well as the data of its operating experience at an LU-10 Linac of NSC KIPT are presented in the article. The procedure and results of calibration of the measuring channels within the electron energy range 8…10 MeV are described.

ЕКСПЕРИМЕНТАЛЬНЕ ДОСЛІДЖЕННЯ ХАРАКТЕРИСТИК ФОТООПОРІВ

The article describes the experimental study of the basic characteristics and parameters of semiconductor photo resistances by students of physics at the Pedagogical University. The study was conducted at a laboratory stand developed, patented and manufactured by us. One of the main components of the professional training of future physics teachers is the formation of skills for organizing and conducting a physical experiment, among them acquiring new knowledge; forming the primary skills of using physical equipment and devices; acquiring the ability to plan the experiment and analyze the results. Our studies have shown that performing only laboratory work according to the prepared instructions, do not yet provide adequate preparation for independent planning and conducting experimental research by students. In order to partially solve the problem of improvement the forms and methods of organizing the initial experiment, we have proposed a pilot work that can be done in the final stage of specialist training. The purpose of the article is to analyze the results of the study of the photographic resistance characteristics that was offered to students. Studies in which was used photoresist, based on sulfur cadmium included: taking of current voltage, light, spectral and frequency characteristics of photo-resists; determination of integral sensitivity of photo-resistance; determining the influence of external factors on the characteristics of semiconductors. Students studied photographic resistance before and after treatment of its working surface with high-energy electron fluxes with a maximum energy of up to 1.15 MeV to identify the influence of external factors on the characteristics and parameters of semiconductors. The semiconductor was irradiated with electrons on an industrial electron accelerator. Involvement of students in experimental work conducted during extracurricular time and under the guidance of the teacher is essential in generalizing generic experimental research skills of future specialists. Key words: physical experiment, semiconductor, photo-resistance, properties.

APPLICATION OF CATHODOLUMINESCENCE FOR ON-LINE MONITORING OF REGIME OF AN INDUSTRIAL ELECTRON ACCELERATOR

Continuous monitoring of critical parameters of an industrial electron accelerator provides quality of product processing. For that purpose, the methods of contact-free diagnostics of processing regime are developed. One of them is based on application of a wide-aperture stack-monitor for on-line measurement of beam current, electron energy, and also the mean absorbed dose over the plain of beam scanning in an irradiated object [1]. In the work, the conditions of application of cathodoluminescence (CL), accompanied action of accelerated electrons on amorphous dielectrics, for adjustment of the stack-monitor, and also for measuring in on-line mode the dose in a point of control as well as of distribution of the electron flux density on the surface of the object, is studied. It is shown, that titanium dioxide, keeping the radiation-optical yield at an accumulated dose of up to 4 MGy, can be considered as a promising material for manufacturing of CL detector.

OPERATION OF AN INDUSTRIAL ELECTRON ACCELERATOR IN A DOUBLE-BEAM e,X-MODE

Analysis of mixed e,X-radiation formation in output devices of an industrial electron accelerator is conducted. The possibility is demonstrated to obtain an extra radiation channel on the basis of a practically free source of Xrays simultaneously with the main channel of product processing with electron beam. The conditions of production of the secondary radiation in the state of electronic equilibrium at product treatment with scanning electron beam in the main radiation channel are studied by means of computer simulation. The dependence of spatial radiant characteristics of the X-ray radiation on the spectrum of a primary electron beam and surface density of a treated load has been established. For an industrial accelerator LU-10 of NSC KIPT, the regime of object processing in the extra radiation channel is examined. The results of calculation of the X-ray dose rate and its spatial distribution are in good agreement with the experimental data. The comparative capacity of both radiation channels of the plant is analyzed. The extra radiation source can be used for the execution of non-commercial programs like sanitation of cultural artefacts.

IMPROVED BURNING DOWN PROTECTION SYSTEM OF INDUSTRIAL ELECTRON ACCELERATORS OUTLET WINDOW FOIL

The results of the industrial electron accelerators protection system deficiencies analysis in the event of emer-gency conditions are given and the ways to improve it are suggested in the article. The principle of the protection system functional scheme operation and its main characteristics are described. The proposed protection system on current windings of horizontal and vertical sweeps can be applied in industrial accelerators of the ELV-1 series.

Magnetic Sweep of a Relativistic Electron Beam into a Rectangular Raster

The design of a magnetic sweep unit that provides a combination of two linear (with respect to time) sweeps of the relativistic electron beam and the radiation field of the accelerated electron beam swept into a rectangular raster and scattered by an air layer when approaching the target have been considered. Expressions for the distribution of absorbed dose over the whole exposed surface have been obtained taking into account the real distribution of beam current density. The considered expressions for the distribution function of absorbed dose can be used as a foundation for the calculations of magnetic sweep units for radiochemical equipment with high-current industrial electron accelerators, in particular, with escape of a focused beam of accelerated electrons into the atmosphere.

Industrial electron accelerators developed at the Budker Institute of Nuclear Physics, SB RAS

In the early 1960s, work on developing industrial high-power electron accelerators was initiated by Academician G I Budker, the founder and director of the Institute of Nuclear Physics (currently, Budker Institute of Nuclear Physics, BINP). This review describes the arrangements and principles of operation of high-power electron accelerators of the ELV and ILU series designed and constructed at the BINP. Since 1972, 170 ELV and more than 50 ILU machines have been shipped to many countries around the world, most of them still operational. International Atomic Energy Agency surveys rate the BINP as one of the few well-trusted global suppliers of reliable industrial accelerators.

A study on beam profile of an industrial electron accelerator

ABSTRACTExperimental evaluation of electron beam profile of a recently upgraded industrial electron accelerator has been carried out to study characteristics of the beam required for the irradiation of various industrial products. Calibrated cellulose triacetate (CTA) film strip dosimeters were used for the measurement of dose profile along and transverse to the scanning direction at different distances in air under the beam extraction window in dynamic (conveyor) and static mode of operation. Two-dimensional dose distribution mapping under the beam has also been measured by using a large number of CTA strip dosimeters. The obtained result shows that the electron beam emerging out from scanning horn has a good uniformity along the scanning direction within 90% of the average maximum dose. Also, the paper reports depth dose distribution in unit density material under the 4.5 MeV beam. Using this study, area affecting dose to the product is controlled within the limit for the irradiation.

Ускорители электронов для промышленного применения, разработанные в ИЯФ им. Г.И. Будкера СО РАН

Ускорители электронов для промышленного применения, разработанные в ИЯФ им. Г.И. Будкера СО РАН

Multi-physics analysis of a 325 MHz bi-periodic on-axis coupled accelerating structure

A 325-MHz bi-periodic on-axis coupled accelerating structure prototype which consists of two bi-periodic accelerating modules is under fabrication in the Institute of High Energy Physics, Beijing, dedicated to a 10-MeV/100 kW industrial linear electron accelerator. According to the beam dynamics study, the average power dissipated in the prototype cavity is about 19.1 kW. Effective cooling scheme is one of the most important issues in the high-power operation. This paper mainly deals with the RF, thermal and structural coupled analyses of the accelerating structure prototype with the help of the ANSYS code. The cooling scheme is optimized to minimize the temperature rise, displacement and von Mises stresses. The temperature and stress distributions in the steady state are presented. The maximum von Mises stress is much lower than the yield strength limit of the corresponding material. The frequency shift caused by the thermal expansion is calculated as well, which is within the scope of the tuning range. The coupled analyses based on the ANSYS software package are presented to design and optimize the cooling scheme of the accelerating structure. The von Mises stresses are much lower than the yield strength limit of the material. The calculation results indicate that our cooling scheme can deal with the dissipated RF power efficiently.

Design and construction of multi-port solid state structure for the Rhodotron accelerator

RF generation and method used for coupling power to the acceleration cavity are important issues in the RF accelerators. In this study, a high power vacuum tube was replaced with several medium power solid state amplifiers coupled through a multi-port structure in the Rhodotron-TT200 accelerator. To this end, a multi-port structure was implemented on a small aluminum model cavity for 1 to 9 ports and all main parameters affecting return loss, quality factor, coupling coefficient and RF power were investigated by calculation, simulation and experimental tests. Then, three 20 kW solid state amplifiers were designed and constructed. The outputs of these amplifiers were coupled to the Rhodotron acceleration cavity by three input ports based on the results obtained from the model cavity for generation of 5 MeV electron beam. In this method, several smaller amplifiers were used instead of a single high power amplifier. As such, acceleration cavity plays the role of power combiner in addition to its primary role and there is no need to a high power combiner. The results showed that the number of ports, port positions, angle between ports and phase of input signals, significantly affect the acceleration electrical field in the cavity. Also, experimental tests revealed that three constructed RF power supplies are enough for the generation of 5 MeV electron beam in the Rhodotron accelerator. Considering the advantages of the solid state amplifiers, application of multi-port structure and solid state amplifiers could be expanded in the industrial electron accelerators.

ILU industrial electron accelerators for medical-product sterilization and food treatment

Pulse linear electron accelerators of the ILU type have been developed and produced by the Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, for more than 30 years. Their distinctive features are simplicity of design, convenience in operation, and reliability during long work under conditions of industrial production. ILU accelerators have a range of energy of 0.7–10 MeV at a power of accelerated beam of up to 100 kW and they are optimally suitable for use as universal sterilizing complexes. The scientific novelty of these accelerators consists of their capability to work both in the electron-treatment mode of production and in the bremsstrahlung generation mode, which has high penetrating power.

Radiation Field Forming for Industrial Electron Accelerators Using Rare-Earth Magnetic Materials

The article describes the radiation field forming system for industrial electron accelerators, which would have uniform distribution of linear charge density at the surface of an item being irradiated perpendicular to the direction of its motion. Its main element is non-linear quadrupole lens made with the use of rare-earth magnetic materials. The proposed system has a number of advantages over traditional beam scanning systems that use electromagnets, including easier product irradiation planning, lower instantaneous local dose rate, smaller size, lower cost. Provided are the calculation results for a 10 MeV industrial electron accelerator, as well as measurement results for current distribution in the prototype build based on calculations.

Design study of double-layer beam trajectory accelerator based on the Rhodotron structure

In this paper, the conceptual design of a new structure of industrial electron accelerator based on the Rhodotron accelerator is presented and its properties are compared with those of Rhodotron-TT200 accelerator. The main goal of this study was to reduce the power of RF system of accelerator at the same output electron beam energy. The main difference between the new accelerator structure with the Rhodotron accelerator is the length of the coaxial cavity that is equal to the wavelength at the resonant frequency. Also two sets of bending magnets were used around the acceleration cavity in two layers. In the new structure, the beam crosses several times in the coaxial cavity by the bending magnets around the cavity at the first layer and then is transferred to the second layer using the central bending magnet. The acceleration process in the second layer is similar to the first layer. Hence, the energy of the electron beam will be doubled. The electrical power consumption of the RF system and magnet system were calculated and simulated for the new accelerator structure and TT200. Comparing the calculated and simulated results of the TT200 with those of experimental results revealed good agreement. The results showed that the overall electrical power consumption of the new accelerator structure was less than that of the TT200 at the same energy and power of the electron beam. As such, the electrical efficiency of the new structure was improved.