Radiation Processing Applications Research Articles

1 MeV, 10 kW DC electron accelerator for industrial applications

Several modern applications of radiation processing like medical sterilization, rubber vulcanization, polymerization, cross-linking and pollution control from thermal power stations etc. require D.C. electron accelerators of energy ranging from a few hundred keVs to few MeVs and power from a few kilowatts to hundreds of kilowatts. To match these requirements, a 3 MeV, 30 kW DC electron linac has been developed at BARC, Mumbai and current operational experience of 1 MeV, 10 kW beam power will be described in this paper. The LINAC composed mainly of Electron Gun, Accelerating Tubes, Magnets, High Voltage source and provides 10 kW beam power at the Ti beam window stably after the scanning section. The control of the LINAC is fully automated. Here Beam Optics study is carried out to reach the preferential parameters of Accelerating as well as optical elements. Beam trials have been conducted to find out the suitable operation parameters of the system.

An Empirical Model for Predicting Harwell Dose Variation During Gamma Process Interruption Using Experimental Design

During routine dosimetry for radiation processing applications, process interruption is widely encountered; in this case dosimeters may receive their target dose in two or more absorbed-dose increments. Some interruptions may be planned, for example double side irradiations may be used to improve dose distribution. Other interruptions may be the result of unplanned irradiator shutdowns. In this case, dosimeters may be exposed to outside factors, such as temperature, without exposure to ionizing radiation. The responses of these dosimeters are usually influenced because the conditions in irradiation facilities may differ considerably from the conditions in which the dosimeters were calibrated. These differences may lead to expected systematic errors in dose estimation. An original approach is proposed in this work in order to simulate a process interruption within limits and quantify the effects of a combination of factors on dosimeter response using complete factorial design 2 n . We present an in-depth experimental study on the response of dosimeters that have been irradiated, stored for a fixed period of time at several temperatures, and then re-irradiated. This study was performed using Harwell Red Perspex dosimeter type 4035.

A new developed radiochromic film for high-dose dosimetry applications

A colorless polyvinyl butyral film (PVB) based on a radiochromic leuco brilliant blue cyanide dye (LBB), was investigated as a high-dose dosimeter for gamma radiation processing applications in the dose range of 3–165 kGy. The useful applications for such dose range are food irradiation treatment, medical devices sterilization, and polymer modification. Upon γ-ray exposure, the prepared film undergoes visual color change to deep blue color characterized with an absorption band peaking at 638 nm. The variation in response of irradiated film stored in the dark and under laboratory light illumination was less than 5% during the first week of storage. The effect of temperature and relative humidity on the performance of film during irradiation and the overall uncertainty associated with absorbed dose monitoring were investigated in the present study.

Study of l-aspartic acid for its possible use as a dosimeter in the interval of 3.4–20kGy at different irradiation temperatures

Abstract Certain commercial applications of radiation processing increase the efficiency of chemical reactions at low temperatures to decrease the free radicals in the bulk material and avoid the synergistic effects of heat. Such applications have motivated the search for a reliable, low-temperature dosimeter for use under the conditions of the irradiation process. For this purpose, polycrystalline samples of l -aspartic acid (2-aminobutanedioic acid) were irradiated with gamma rays at low temperatures and doses in the kiloGray range (3.4–64 kGy). The potential use of the aspartic acid system as a chemical dosimeter is based on the formation of stable free radicals when the amino acid is exposed to ionizing radiation. These radicals can be studied and quantified using electron spin resonance (ESR). The response curves at different temperatures show that the intensity of the ESR spectra (the five characteristic lines) depends on the dose received. The response of the dosimeter increases with increasing temperature, and this relationship is linear up to 20 kGy at 298 K. The decay characteristics show that the change in the ESR signal over time is low and reproducible. In addition, the l -aspartic acid dosimeter is easy to handle and has low cost.

A radiochromic film based on leucomalachite green for high-dose dosimetry applications

A colorless polyvinyl butyral film (PVB) based on radiation-sensitive dye of leucomalachite green (LMG) was investigated as a high-dose dosimeter for gamma radiation processing applications in the dose range of 3–150 kGy. The useful applications for such dose range are food irradiation treatment, medical devices sterilization and polymer modification. Gamma irradiation of the film induces a significant intensity of green color, which can be characterized by a main absorption band at 627 nm and a small band at 425 nm. The variation in response of irradiated film stored in the dark and under laboratory light illumination was less than 3% during the first 6 days of storage. The response of film during irradiation was slightly influenced by relative humidity in the range of 12–76%; however, it was significantly affected by temperature in the range of 5–40 °C. The radiation chemical yield was reported to be 6.76 × 10−6 mol/J at the absorbed dose of 30 kGy for the film containing 6.5% of LMG dye. The overall uncertainty associated with routine dose monitoring would be less than 6% at a 95% confidence level if the dosimeter was being corrected for irradiation conditions and being calibrated with reference standard dosimeter in the production facility.

Thermoluminescence glow-curve characteristics of LiF phosphors at high doses of gamma radiation

High doses of ionising radiation are becoming increasingly common for radiation-processing applications of various medical, agricultural and polymer products using gamma and electron beams. The objective of this work was to study thermoluminescence (TL) glow-curve characteristics of commonly used commercial LiF TL phosphors at high doses of radiation with a view to use them in dosimetry of radiation-processing applications. The TL properties of TLD 100 and 700 phosphors, procured from the Thermo-Scientific (previously Harshaw) company, have been studied in the dose range of 1–60 kGy. The shift in glow peaks was observed in this dose range. Integral TL responses of TLD 100 and TLD 700 were found to decrease as a linear function of dose in the range of 5–50 kGy. The paper describes initial results related to the glow-curve characteristics of these phosphors.

Development of EPR dosimeters based on SiO2 for possible use in radiation processing applications

Development of EPR dosimeters based on SiO2 for possible use in radiation processing applications

A genipin-gelatin gel dosimeter for radiation processing

Genipin, a fruit extract from Gardenia jasminoides Ellis, forms cross-links in solutions of gelatin, to form a blue hydrogel that bleaches quantitatively upon irradiation and the colour change can be measured with a spectrophotometer. With the addition of sulphuric acid this dosimeter is sufficiently sensitive for quality assurance of radiotherapy level dosimetry. Without sulphuric acid the gel has a reduced sensitivity and responds linearly with dose between 100 and 1000Gy, making it potentially useful as a dosimeter for radiation processing applications such as the phytosanitary irradiation treatment of food. We investigated the dose response characteristics of this new formulation and found that the darker gels are more sensitive to dose and have a reduced uncertainty.

Application of Radiation Processing of Materials to Increase Sharpness of <I>p</I>–<I>n</I>-Junction in a Semiconductor Heterostructure

Application of Radiation Processing of Materials to Increase Sharpness of <I>p</I>–<I>n</I>-Junction in a Semiconductor Heterostructure

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.

Temperature effect on the gamma dose response of glycine (spectrophotometric read-out) system

Abstract The glycine (spectrophotometric read-out) dosemeter has a useful dose range of 15–4000 Gy with good reproducibility and post-irradiation stability. It is a potential dosemeter for radiation processing applications, but the dose response of the system may vary with irradiation and measurement temperature. The effect of irradiation and variation in measurement temperature on the gamma dose response of this system was investigated. The gamma dose response was found to be constant for both irradiation and measurement temperatures ranging from 10 to 50 °C, and the maximum variation in response is within ±1%.

Applications of radiation processing in combination with conventional treatments to assure food safety: New development

Spice extracts under the form of essential oils (Eos) were tested for their efficiency to increase the relative bacterial radiosensitivity (RBR) of Listeria monocytogenes, Escherichia coli and Salmonella typhi in culture media under different atmospheric conditions. The selected Eos were tested for their ability to reduce the dose necessary to eliminate E. coli and S. typhi in medium fat ground beef (23% fat) and Listeria in ready-to-eat carrots when packed under air or under atmosphere rich in oxygen (MAP). Results have demonstrated that depending of the compound added and the combined treatment used, the RBR increased from 2 to 4 times. In order to evaluate the industrial feasibility, EOs were added in ground beef at a concentration which does not affect the taste and treated at a dose of 1.5 kGy. The content of total mesophilic aerobic, E. coli, Salmonella, total coliform, lactic acid bacteria, and Pseudomonas was determined during 28 days. The results showed that the combined treatment (radiation and EOs) can eliminate Salmonella and E. coli when done under air. When done under MAP, Pseudomonas could be eliminated and a shelf life of more than 28 days was observed. An active edible coating containing EOs was also developed and sprayed on ready-to-eat carrots before radiation treatment and Listeria was evaluated. A complete inhibition of Listeria was obtained at a dose of 0.5 kGy when applied under MAP. Our results have shown that the combination of an edible coating, MAP, and radiation can be used to maintain the safety of meat and vegetables.

Prospects and challenges in application of gamma, electron and ion beams in processing of nanomaterials

Application of radiation techniques for nanotechnology has been known for years. X-ray, electron beam and ion beam lithography are good examples of applications. By using electron beams, ion beams and X-rays structures as small as 10 nm can be produced. Ion track membranes with track diameters from 10 nm to 100 nm are used as such or as templates for electroplating of nanowires of metal, semiconductor and magnetic materials. In the near future X-rays, focused ion beams and electron beams will be used for nanolithography and 3D fabrication; heavy ion beams on the other hand can be useful for fabrication of nanopores and nanowires. The use of radiation has proved to be an essential technique in the fabrication of nanostructures with high resolution as the radiation beams can be focused into few nanometer scales or less. Three groups of products could be considered to be fabricated by radiation techniques: nanoparticles, nanogels and nanocomposites. These and other possible fields of radiation processing applications in nanotechnology are discussed in the paper.

Radiochromic film containing methyl viologen for radiation dosimetry

Poly(vinyl alcohol) (PVA) films containing methyl viologen (MV 2+) that colours blue upon exposure to ionizing radiation were investigated as possible dosimeters for use in radiation processing applications. In order to find the most suitable composition of the PVA-MV 2+ film, different concentrations of the dye have been studied. The absorbance values at selected wavelengths, obtained from irradiation of the PVA film containing the most suitable MV 2+ concentration, can be satisfactorily related to the absorbed dose over a wide range, from 50 Gy up to 40 kGy. The effects of dose, dose rate, humidity and temperature on the response of the PVA-MV 2+ dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV 2+ is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations.

Industrial applications of electron beam flue gas treatment—From laboratory to the practice

The electron beam technology for flue gas treatment (EBFGT) has been developed in Japan in the early 1980s. Later on, this process was investigated in pilot scale in the USA, Germany, Japan, Poland, Bulgaria and China. The new engineering and process solutions have been developed during the past two decades. Finally industrial plants have been constructed in Poland and China. The high efficiency of SO x and NO x removal was achieved (up to 95% for SO x and up to 70% for NO x ) and by-product is a high quality fertilizer. Since the power of accelerators applied in industrial installation is over 1 MW and requested operational availability of the plant is equal to 8500 h in year, it is a new challenge for radiation processing applications.

Radiation effects on alanine; thermal approach for estimation of low absorbed radiation doses

Irradiated alanine when heated in differential scanning calorimetry cell (DSC) gives thermal profiles which have varying decomposition temperatures correlated to absorbed radiation dose between 0 to 250 Gy with high precision. Higher absorbed doses give characteristic decomposition peaks in DSC thermal profile. DSC studies indicate that changes in the thermal profiles are mainly due to exothermic decomposition of peroxides. Based on the information, it may be possible to develop a low cost and simple thermal device for estimating low absorbed doses in industrial radiation processing applications.

Prospects for the application of radiation processing and the activities of the IAEA

Ion exchange adsorbents based on cellulosic fabric wastes carrying sulfonic acid and amine functional groups were synthesized by radiation-induced graft polymerization of glycidyl methacrylate (GMA) with subsequent chemical modification of the epoxy groups of poly-GMA graft chains with sodium sulfite/H2SO4 and triethylamine, respectively. The conversion of epoxy groups into the functional groups was investigated. Factors affecting on grafting process such as radiation dose, monomer concentration and solvent were studied. The synthesized adsorbent and its applications in the removal of different types of hazardous pollutants e.g. acidic dye, cobalt, dichromate and phenols from aqueous solution were also studied.

New trends of radiation processing applications

Major fields of radiation processing applications are: polymeric materials, food processing, sterilization of medical products and environmental conservation. There are about 200 60Co gamma irradiation facilities and 700 electron beam accelerators, mainly for commercial purposes, throughout the world. Radiation cross-linking and grafting techniques of polymeric materials have been providing many unique products including heat materials, heat shrinkable materials, curing of coatings and battery separators. Extensive studies have been devoted to the development of bio-medical materials using radiation processing to prepare bio-compatible materials and controlled release of drugs. New wound dressings have been successfully developed in Poland and Israel for commercial clinical use.

Application of radiation processing in asia and the pacific region: Focus on malaysia

Applications of radiation processing in Malaysia and other developing countries in Asia and the Pacific region is increasing as the countries move toward industrialisation. At present, there are more than 85 gamma facilities and 334 electron accelerators in Asia and the Pacific region which are mainly in Japan, Rep. of Korea and China. The main applications which are in the interest of the region are radiation sterilisation of medical products; radiation crosslinking of wire and cable, heat shrinkable film and tube, and foam; radiation curing of surface coatings, printing inks and adhesive; radiation vulcanisation of natural rubber latex; radiation processing of agro-industrial waste; radiation treatment of sewage sludge and municipal waste; food irradiation; tissue grafts and radiation synthesis of bioactive materials.

Effects of temperature and humidity during irradiation on the response of a film dosimeter

A commercially available leuco dye containing polyvinyl butyral based film (FWT-63-02) has been investigated ctrophotometrically for its dosimetric characteristic and for its use as routine dosimeter in radiation processing for the absorbed dose range 0.1 to 10 kGy. The present study was carried out to evaluate the performance of dosimeter under different environmental conditions (i.e. effects of temperature and relative humidity during irradiation). The response was measured at peak wavelength of 600 nm as well as at a number of other wavelengths (550, 625, 640 and 650 nm). The dosimeter was found to show quite stable response up to a radiation chamber temperature of 40°C. The dosimeter also showed stable behavior at low or moderate relative humidity conditions (<76%) in the radiation chamber. The characteristics of the dosimeter are suitable for its possible application in radiation processing, food irradiation and sterilization applications.