scholarly journals Economical evaluation of radiation processing with high-intensity X-rays

Nukleonika ◽  
2020 ◽  
Vol 65 (3) ◽  
pp. 167-172
Author(s):  
Zbigniew Zimek
Keyword(s):  
Electron Beam ◽  
Electron Energy ◽  
High Power ◽  
High Intensity ◽  
Power Level ◽  
Unit Cost ◽  
Utilization Efficiency ◽  
Beam Power ◽  
X Rays ◽  
Radiation Processing

AbstractX-rays application for radiation processing was introduced to the industrial practice, and in some circumstances is found to be more economically competitive, and offer more flexibility than gamma sources. Recent progress in high-power accelerators development gives opportunity to construct and apply reliable high-power electron beam to X-rays converters for the industrial application. The efficiency of the conversion process depends mainly on electron energy and atomic number of the target material, as it was determined in theoretical predictions and confirmed experimentally. However, the lower price of low-energy direct accelerators and their higher electrical efficiency may also have certain influence on process economy. There are number of auxiliary parameters that can effectively change the economical results of the process. The most important ones are as follows: average beam power level, spare part cost, and optimal shape of electron beam and electron beam utilization efficiency. All these parameters and related expenses may affect the unit cost of radiation facility operation and have a significant influence on X-ray process economy. The optimization of X-rays converter construction is also important, but it does not depend on the type of accelerator. The article discusses the economy of radiation processing with high-intensity of X-rays stream emitted by conversion of electron beams accelerated in direct accelerator (electron energy 2.5 MeV) and resonant accelerators (electron energy 5 MeV and 7.5 MeV). The evaluation and comparison of the costs of alternative technical solutions were included to estimate the unit cost of X-rays facility operation for average beam power 100 kW.

Some of these could also be operated in the energy range above lOMeV for experiments designed to determine at which energy level radioactivity can be induced in the irradiated medium. A linac with a maximum energy of 25 MeV was commissioned for the U.S. Army Natick Research and Development Labora­ tories in 1963. Its beam power was 6.5 kW at an electron energy of 10 MeV, 18 kW at 24 MeV. Assuming 100% efficiency, a 1-kW beam can irradiate 360 kg of product with a dose of 10 kGy/h. The efficiency of electron accelerators is higher than that of gamma sources because the electron beam can be directed at the product, whereas the gamma sources emit radiation in all directions. An efficiency of 50% is a realistic assumption for accelerator facilities. With that and 6.5 kW beam power an accelerator of the type built for the Natick laboratories can process about 1.2t/h at 10 kGy. In Odessa in the former Soviet Union, now in the Ukraine, two 20-kW accelerators with an energy of 1.4 MeV installed next to a grain elevator went into operation in 1983. Each accelerator has the capacity to irradiate 200 t of wheat per hour with a dose of 200 Gy for insect disinfestation. This corresponds to a beam utilization of 56% (9). In France, a facility for electron irradiation of frozen deboned chicken meat commenced operation at Berric near Vannes (Brittany) in late 1986. The purpose of irradiation is to improve the hygienic quality of the meat by destroying salmonella and other disease-causing (pathogenic) microorganisms. The electron beam accelerator is a 7 MeV/10 kW Cassitron built by CGR-MeV (10). An irradiation facility of this type is shown in Figure . Because of their relatively low depth of penetration electron beams cannot be used for the irradiation of animal carcasses, large packages, or other thick materials. However, this difficulty can be overcome by converting the electrons to x-rays. As indicated in Figure 9, this can be done by fitting a water-cooled metal plate to the scanner. Whereas in conventional x-ray tubes the conversion of electron energy to x-ray energy occurs only with an efficiency of about %, much higher efficiencies can be achieved in electron accelerators. The conversion efficiency depends on the material of the converter plate (target) and on the electron energy. Copper converts 5-MeV electrons with about 7% efficiency, 10-MeV electrons with 12% efficiency. A tungsten target can convert 5-MeV electrons with about 20%, 10-MeV electrons with 30% efficiency. (Exact values depend on target thickness.) In contrast to the distinct gamma radiation energy emitted from radionuclides and to the monoenergetic electrons produced by accelerators, the energy spectrum of x-rays is continuous from the value equivalent to the energy of the bombarding electrons to zero. The intensity of this spectrum peaks at about one-tenth of the maximum energy value. The exact location of the intensity peak depends on the thickness of the converter plate and on some other factors. As indicated in Figure

1995 ◽  
pp. 40-40
Keyword(s):  
Electron Beam ◽  
Electron Energy ◽  
Maximum Energy ◽  
Metal Plate ◽  
Beam Power ◽  
X Rays ◽  
X Ray ◽  
Emit Radiation ◽  
Electron Accelerators ◽  
Gamma Sources

Surface and Adhesive Properties of Low-Density Polyethylene after Radiation Cross-Linking

2014 ◽  
Vol 606 ◽  
pp. 265-268 ◽  
Author(s):  
Martin Bednarik ◽  
David Manas ◽  
Miroslav Manas ◽  
Martin Ovsik ◽  
Jan Navratil ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Performance ◽  
Chemical Properties ◽  
Low Density Polyethylene ◽  
Cross Linking ◽  
Low Density ◽  
X Rays ◽  
Radiation Processing ◽  
Adhesive Properties ◽  
Γ Rays

Radiation cross-linking gives inexpensive commodity plastics and technical plastics the mechanical, thermal, and chemical properties of high-performance plastic. This upgrading of the plastics enables them to be used in conditions which they would not be able to with stand otherwise. The irradiation cross-linking of thermoplastic materials via electron beam or cobalt 60 (gammy rays) is performed separately, after processing. Generally, ionizing radiation includes accelerated electrons, gamma rays and X-rays. Radiation processing with an electron beam offers several distinct advantages when compared with other radiation sources, particularly γ-rays and x-rays. The process is very fast, clean and can be controlled with much precision. There is no permanent radioactivity since the machine can be switched off. In contrast to γ-rays and x-rays, the electron beam can steered relatively easily, thus allowing irradiation of a variety of physical shapes. The energy-rich beta rays trigger chemical reactions in the plastics which results in networking of molecules (comparable to the vulcanization of rubbers which has been in industrial use for so long). The energy from the rays is absorbed by the material and cleavage of chemical bonds takes place. This releases free radicals which in next phase from desired molecular bonds. This article describes the effect of radiation cross-linking on the surface and adhesive properties of low-density polyethylene.

A New X-Ray Lens and its Applications

1993 ◽  
Vol 37 ◽  
pp. 507-514
Author(s):  
Yan Yiming ◽  
Ding Xunliang ◽  
Wang Dachun
Keyword(s):  
Power Density ◽  
High Power ◽  
Large Angle ◽  
Utilization Efficiency ◽  
X Rays ◽  
X Ray ◽  
Small Spot

In the late 1980s, a new X-ray focusing system, X-ray lens, capable of adjusting and controlling high power, white X-ray beams, has been created. This X-ray lens can collect X-rays in a large angle range, increasing the utilization efficiency of an Xray source. It can focus X-rays into a small spot, improving X-ray power density 104 to 106 times when compared to the same source at the same distance without the focusing system. It can also transfer diverging X-ray beam to a nearly parallel one. These properties make the focusing system potentially useful in many Xray applications.

kW electron beam would thus process 180 kg of food or other materials, the 67,578-Ci 60Co would process 108 kg, and the 308,641-Ci 137Cs would process 72 kg, always with a dose of lOkGy in 1 h. If a 5-MeV electron beam were converted to x-rays with % efficiency and the x-ray beam were absorbed by the irradiated food with 50% efficiency, the electron beam power would have to be about 14.5 kW to process 180 kg with a dose of 10 kGy/h (12). If we recalculate this in each case for a throughput of 1.8t/h, the beam power or source load indicated in Table 2 is obtained. Many 60Co sources of this size exist all over the world, but not a single 137Cs source approaching 7 MCi exists anywhere. Electron accelerators of the capacity indicated in Table 2 are commer­ cially available. The possible throughput is only one of the parameters that influence the choice of a particular type of irradiator. Many other technical, economical, and, increas­ ingly, sociopolitical aspects must be taken into consideration. Technical considerations refer primarily to the different penetrating power of various types of radiation and to differences in dose rate. If large crates of potatoes are to be irradiated, it is obvious that a gamma source rather than an electron irradiator must be chosen. When the two types of gamma sources are compared, it must be considered that the use of Co, due to the higher penetrating

1995 ◽  
pp. 43-43
Keyword(s):  
Electron Beam ◽  
Dose Rate ◽  
Beam Power ◽  
X Rays ◽  
137Cs Source ◽  
Gamma Source ◽  
Electron Accelerators ◽  
The World ◽  
Gamma Sources ◽  
Technical Considerations

Microanalysis with high Spatial Resolution

1983 ◽  
Vol 31 ◽  
Author(s):  
P. E. Batson ◽  
C. R. M. Grovenor ◽  
D. A. Smith ◽  
C. Wong
Keyword(s):  
Electron Beam ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Electron Energy ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
X Rays ◽  
Elemental Microanalysis ◽  
Bulk Plasmon ◽  
Electron Energy Loss

ABSTRACTElemental microanalysis, using x-rays and electron energy loss scattering, has been shown to be possible with electron beam probe sizes down to 0.5nm. This paper will discuss some practical problems, such as specimen drift, signal magnitude, and probe-specimen interaction when the probe is made very small. These problems have arisen in two studies: 1) an investigation of as segregation in poly-crystalline Si and 2) imaging of metal spheres with surface and bulk plasmon inelastic scattering.

scholarly journals Преобразование частоты излучения мощных гиротронов в условиях обратного рамановского рассеяния на дополнительном электронном пучке

2019 ◽  
Vol 45 (4) ◽  
pp. 13
Author(s):  
Н.С. Гинзбург ◽  
Л.А. Юровский ◽  
И.В. Зотова ◽  
А.С. Сергеев
Keyword(s):  
Electron Beam ◽  
Electron Energy ◽  
High Power ◽  
Scattered Radiation ◽  
Frequency Conversion ◽  
Scattered Signal ◽  
Absolute Instability ◽  
Radiation Frequency ◽  
The Absolute

AbstractThe regime of Raman backscattering of a pumping wave that is cocurrent with an electron beam into the counterpropagating wave can be used for the radiation frequency conversion in high-power gyrotrons. The absolute instability developing in this system ensures generation of a scattered signal in the absence of external resonators, which allows the frequency of scattered radiation to be smoothly controlled within 20–40% by varying the electron energy in the case of high-power (megawatt) gyrotrons used as sources of pumping radiation.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

A New High Intensity Grid Cap for RCA-EMU-3 Electron Microscopes

1968 ◽  
Vol 26 ◽  
pp. 316-317
Author(s):  
George Christov ◽  
Bolivar J. Lloyd
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
High Voltage ◽  
High Intensity ◽  
Electron Gun ◽  
Tungsten Filament ◽  
Fluorescent Screen ◽  
Electron Microscopes ◽  
Pass Through ◽  
Ground Potential

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.

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