Electron Beam Dose Research Articles

Synergistic effect of polyurethane‐coated carbon fiber and electron beam irradiation on the thermal/mechanical properties and long‐term durability of polyamide‐based thermoplastic composites

AbstractTo attain thermoplastic polymer composites with enhanced thermal and mechanical properties as well as long‐term durability, in this study, polyurethane‐coated carbon fiber (CF) and electron beam (EB) irradiation are adopted as an effective reinforcing filler and efficient crosslinking process, respectively. For this purpose, polyamide 6 (PA)‐based composites with different CF contents of 1–10 wt% were fabricated through melt‐compounding and compression molding, and then irradiated with various EB doses of 50–200 kGy. The SEM and FT‐IR data reveal that CFs are well dispersed in the PA matrix with excellent interfacial adhesion via specific intermolecular interactions, which are even enhanced for the composites with crosslinked PA matrices after the EB irradiation. As the result, the thermal stability (initial decomposition temperature and residue at 800°C) and dynamic mechanical properties of PA/CF composites increased noticeably with increasing the CF content and EB irradiation dose. The initial storage modulus of 1.90 GPa for neat PA at 30°C was improved significantly to 2.94 GPa by 10 wt% CF addition and to 4.67 GPa by 200 kGy EB irradiation. In particular, the long‐term mechanical properties of PA/CF composites, which were evaluated using a stepped isothermal method based on the time–temperature superposition principle, were found to be highly enhanced by the synergistic effect of CF filler reinforcement, EB‐induced PA matrix crosslinking, and improved interfacial adhesion.

A comparitive study on morphology, solution properties of electron beam and gamma irradited edible starch

Comparison in solution and morphology properties of electron beam and gamma irradiated potato starch are investigated. In the present work, the authors investigated the changes in solution properties, morphology, granular size and blue value on radiation dose of both electronbeam, gamma radiations. The studies indicate that surface morphology of granules is altered by both the radiations but damage is more in electronbeam irradiation. Viscosity of un- irradiated starch solutions appears to have non – Newtonian behavior; while irradiation led the solutions to have Newtonian nature. This is attributed to the damage in chemical structure caused by both the radiation. Blue index of non-irradiated and irradiated starches are measured and the changes are assigned due to variations in amylose content brought by radiation.

Process monitoring of electron-beam based writing of semiconductor mask patterns

As mask capabilities advance to support optical lithography, mask-making processes become more complex and therefore require more sophisticated monitoring to ensure manufactured masks are defect-free. We present a methodology that aggregates process signatures from writings of different mask patterns under nominal process conditions and detects anomalous process behaviors during writings of new mask patterns. The new approach was demonstrated using simulated electron beam writing of integrated circuit patterns subjected to inconsistent electron beam dosage and spot size. Anomalous process behaviors were detected and tracked quantitatively even if new mask patterns were unlike past mask patterns.

Implementation of Beam Matching Concept for the New Installed Elekta Precise Treatment System Medical LINACs in Indonesia

A concept of radiation beam matching of some medical linear accelerators (LINACs) that have identical characteristics of the models, radiation quality, and multileaf collimator features may be implemented as long as the manufacturer provides complete specifications so that a Treatment Planning System (TPS) can be used for many beam-matched LINACs. This paper describes a preliminary study on the implementation of the beam matching concept for five units Elekta Precise Treatment System LINACs that have recently been installed in Indonesia. The beam matching criteria were based on the percentage depth dose (PDD) and beam profile for photon and electron beams. Dosimetry measurements were carried out by using an SNC 125 ionization chamber of 0.125 cm 3 in volume, PTW Pinpoint 3D of 0.016 cm 3 in volume, and PTW Farmer Chamber of 0.6 cm 3 in volume. The results indicated that the PDD 10 of 6 and 10 MV photon beams among installed five units LINACs have excellent compatibility each others with a maximum deviation of less than 0.4 %, while the maximum deviation for dose depth of 80 % (R 80 ) for the electron beams with nominal energies of 4, 6, 8, 10, 15 and 18 MeV is 1 mm. The measurement results for the flatness profile were less than 6 %, and symmetry profiles were less than 3 %. It also outlines the determination of the absorbed dose to water under reference conditions. The results of the calibration of output doses show that the absorbed dose in the water was 1 cGy ≈ 1 MU. The data obtained from measurements for each LINAC conform with the requirements of the beam matching process set by the manufacturer.

Personalized 3D-printed anthropomorphic phantoms for dosimetry in charged particle fields

Anthropomorphic phantoms used for radiation dose measurements are designed to mimic human tissue in shape, size, and tissue composition. Reference phantoms are widely available and are sufficiently similar to many, but not all, human subjects. 3D printing has the potential to overcome some of these shortcomings by enabling rapid fabrication of personalized phantoms for individual human subjects based on radiographic imaging data. Objective. The objective of this study was to test the efficacy of personalized 3D printed phantoms for charged particle therapy. To accomplish this, we measured dose distributions from 6 to 20 MeV electron beams, incident on printed and molded slices of phantoms. Approach. Specifically, we determined the radiological properties of 3D printed phantoms, including beam penetration range. Additionally, we designed and printed a personalized head phantom to compare results obtained with a commercial, reference head phantom for quality assurance of therapeutic electron beam dose calculations. Main Results. For regions of soft tissue, gamma index analyses revealed a 3D printed slice was able to adequately model the same electron beam penetration ranges as the molded reference slice. The printed, personalized phantom provided superior dosimetric accuracy compared to the molded reference phantom for electron beam dose calculations at all electron beam energies. However, current limitations in the ability to print high-density structures, such as bone, limited pass rates of 60% or better at 16 and 20 MeV electron beam energies. Significance. This study showed that creating personalized phantoms using 3D printing techniques is a feasible way to substantially improve the accuracy of dose measurements of therapeutic electron beams, but further improvements in printing techniques are necessary in order to increase the printable density in phantoms.

Fabrication of Alq3/PMMA nanocomposite sheet and its potential applications as radiation dosimeter

Tris (8-hydroxyquinoline) aluminum (Alq3) is a highly luminescent organometallic compound, and therefore has numerous applications in electronic devices. Its unique optical property is suitable for organic light-emitting diodes, optoelectronic, and photodiodes. Despite its numerous potentials, no study investigated its response to ionizing radiation, particularly in its nanostructure form. In this work Alq3 were incorporated in a highly transparent polymethyl methacrylate (PMMA) polymer sheet using chloroform as a proper solvent for both materials. The ratio of Alq3 to PMMA powders was fixed at 1:10. The resulting composite showed recrystallized fine nanoparticles of Alq3, uniformly embedded in the PMMA sheet. Then small pieces of this nanocomposite sheet were exposed to various doses of X-ray and electron beam (E-beam) radiation doses in the range of 5–20 Gy. The molecular fingerprint and optical emission properties of the pristine and irradiated nanocomposite sheets were evaluated using Raman and PL spectroscopy. A systematic increase in the PL and Raman signals with increasing radiation doses were recorded. In addition, blueshift in the PL peak positions of nearly 6 and 9 nm for X-ray and E-beam irradiated sheets, respectively were also observed. These increments were attributed to the formation of radiative vacancies in the Alq3 molecules while the blueshift might be related to possible weakening of some of the Alq3 bonds such as C-O, C-C, C-H and Al-O, respectively. Therefore, the systematic changes in the optical properties might serve as preliminary parameters to investigate its potential use in radiation dosimetry following its nearly excellent linear dose dependence on signal intensities, which are quite encouraging.

Effects of Irradiation on Surface Charge and Discharge Behaviors of PI Film Under Pulse Voltage

The superconducting magnet, as a main component of the international thermonuclear experimental reactor (ITER), is critical to the ITER's long-term stability. Polyimide (PI) not only has excellent electrical properties at cryogenic temperature, but also has strong irradiation resistance, which has become the common choice of insulating materials for the superconducting magnet. Due to the pulsed power supply used in the ITER, PI is facing the dual challenges of cryogenic temperature and pulsed voltage. The surface charge characteristics of irradiated PI film by different doses of electron beam were studied in this paper. The surface charging is completed under the pulse voltage with 40% relative humidity. The partial discharge initial voltage (PDIV) and breakdown voltage in liquid nitrogen (LN <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) were measured by electrostatic voltmeter. The findings indicate that proper irradiation can help to minimize charge accumulation and decrease the trap level. At the same time, the PDIV and breakdown voltage can be increased by irradiation. However, too much irradiation can weaken this influence.

Striking complexity of the photon field in medical devices with heterogeneous density distribution and challenges for industrial irradiators

Despite the emergence of electron beam sterilization, photons are, and most likely will remain the most commonly used agents for radiation sterilization of medical devices. While it is generally accepted that dose gradients have to be carefully addressed in electron beam dose mapping experiments, photon fields are regarded as permissively with respect to performance qualification and aroused little attention for systematic studies.In this paper a computational approach utilizing Monte Carlo simulation is taken to study dose characteristics from cobalt-60 and X-ray sources. The Compton effect as most important interaction mechanism and its impact on dose distribution are studied in detail. The core of the paper deals with attenuation effects by high density objects, particularly steel cylinders, where the dose along the circumference is computed for parallel photons of different energies, colbalt-60 and 7 MeV X-rays. Model results are validated by dedicated experiments in Co-60 and X-ray irradiators.The paper summarizes that dose distributions in photon field show a striking complexity for inhomogeneous materials, especially when photons are collimated in a parallel beam. In general, results suggest that more attention needs to be paid to dose gradients in performance qualification of medical devices with an inhomogeneous mass distribution and generic dosimeter grids inspired from operational qualification are not appropriate.

Improving Clinical dosimetric Accuracy of cancer treatment using a special quality of Electron and Photon Beam

In external beam radiation therapy, electron and photon beams have extraordinary characteristics in the treatment of cancer. The electron and photon beam characteristic are essential to study before calibration of machine. This study focused on the dosimetric characteristics of different energies of electron beams for different field size. The basic objective of this work is, to calculate dosimetric parameters and characteristics of electron beam, specially depth dose characteristics along central axis. In this work, 6 MeV, 9 MeV, 12 MeV, 15 MeV and 18 MeV of electron beam and 6 MV and 15 MV of photon beam with different field size is used. Characteristics of depth dose of electron and photon beam in water have analyzed to provide better quality of radiation therapy treatment planning. The different beam characteristics are due to different interactions that occurs between electron beams giving them a definite range whereas photon beams are attenuated leading to dose deposition and much larger range with no definite end. Depth dose characteristics of electron and photon beams do not show same characteristics as interaction of beam with matter depends on the quality of beam. Attenuation and penetration factors change with changing dosimetric parameters. Complete analysis of dosimetric characteristics of electron and photon beam help to choose more accurate beam for the treatment of cancer. This work will help to increase accuracy in treatment of cancer with radiotherapy.

Improving Clinical dosimetric Accuracy of Cancer Treatment Using a Special Quality of Electron and Photon Beam

Electron and photon beams demonstrate extraordinary characteristics useful for the treatment of cancer. These characteristics are essential to analyze before the calibration of the linear accelerator with dual energies. This study focused on the dosimetric characteristics of the different energies of electron beam for different field sizes. The basic objective of this work was to calculate the dosimetric parameters and characteristics of the electron beam, especially depth dose characteristics along the central axis. In this work, 6 MeV, 9 MeV, 12 MeV, 15 MeV and 18 MeV of electron beam and 6 MV and 15 MV of photon beam with different field sizes were used. The characteristics of the depth dose of electron and photon beams in water were analyzed to optimize the radiation quality for radiation treatment planning. The different beam characteristics are due to different interactions that occur between electron beams giving them a definite range, whereas photon beams are attenuated leading to dose deposition and a much larger range with no definite end. Depth dose characteristics of electron and photon beams are not similar since the interaction of these beams with matter depends on their quality. Attenuation and penetration factors change with changing dosimetric parameters. A complete analysis of the dosimetric characteristics of electron and photon beams helps to choose the more accurate beam for the treatment of cancer. This work helps to increase accuracy in the treatment of cancer with radiotherapy.&#x0D; Copyright(c) The Authors

Influence of monomer structure and dose rate on kinetic elements in electron-beam polymerizations

In electron-beam (EB) polymerizations, altering the dose rate can cause property changes in the cured polymer, such as conversion, glass transition temperature (Tg), and physical or mechanical properties. These dose rate effects (DREs) complicate scale-up of EB polymerizations in industrial processes. A predictive relationship between DRE and changes in Tg was used to determine that DREs correlate to the number and lability of available bonds, not monomer size. Furthermore, the relationship between the primary radicals produced during EB irradiation and dose rate was explored via measurement of primary radical radiation chemical yield, G(R•). Namely, G(R•) is independent of dose rate, and instantaneous primary radical concentration is directly proportional to dose rate. Moreover, it was shown that non-reciprocity between dose rate and the rate of polymerization results in DREs. Future developments in radiation chemical yield measurements will aid in determining whether this disproportionality is due to the impact of dose rate on the concentration of propagating radicals or on the kinetic mechanism itself.

A new calorimetric method for measuring the absolute dose of high-energy electron beams by digital holographic interferometry

A new calorimetric method for measuring the absolute dose of high-energy electron beams by digital holographic interferometry

Induction of novel variants in Chrysanthemum morifolium through electron beam radiation

Un-rooted cuttings of chrysanthemum varieties Pusa Chitraksha, Pusa Anmol and Basanti were treated with Electron Beam (EB) radiation (20 Gy and 30 Gy) with an objective of inducing variability and evaluated at ICAR-DFR, Pune during 2020. A gradual and significant reduction in vital plant growth parameters was observed with increase in doses. Influence of EB radiation (at 30Gy) on plant height (-34.55%), plant spread (-28.60%), internode length (-39.04%), leaf length (-26.95%), leaf width (-29.28%), number of flowers per plant (-23.28%) and for flower diameter (-24.80%) in comparison to control was recorded. Delay in days to bud initiation and flowering at higher dose (30 Gy) were 13.47 days and 17.33 days, respectively over control. Among the varieties, Pusa Chitraksha was found superior for most of the vegetative growth and flowering parameters. However, it exhibited delay in bud initiation (95.80 days) and flowering (118.0 days). The trend is similar for other two varieties at higher dose. In the interaction effect (Variety x EB dose), plant height (17.00 cm) was very less in variety Basanti at 30 Gy dose. Flower diameter (3.26 cm) was reduced with increased EB dose (30 Gy) in Pusa Aditya compared to control (5.24 cm). Pusa Chitraksha exhibited variation in flower colour (Magenta to white/ cream colour) and Pusa Aditya produced red colour flower at 30 Gy. Based on the study, it can be inferred that Electron Beam at 20-30 Gy had potential to create variation in chrysanthemum.

Degradation of PFOS and PFOA in soil and groundwater samples by high dose Electron Beam Technology

Remediation technologies are urgently needed to degrade poly – and per fluoroalkyl substances (PFAS) in groundwater and soils. Since high energy electron beam (eBeam) technology involves rapid oxidation and reduction reactions it has the potential to breakdown PFAS. In this study, the technology was applied to PFAS-contaminated groundwater and soil samples to degrade PFOS and PFOA and other PFAS. An eBeam dose of 2000 kGy (kGy) reduced PFOS and PFOA concentrations in groundwater by 87.9% and 53.7% respectively. In soils with 10% moisture content, PFOS and PFOA concentrations were reduced by 99.9% and 86.5%, respectively. Out of 17 different PFAS that were detected in the soil sample, the 2000 kGy dose was able to degrade 10 PFAS to below detectable levels: PFNA (initially 19.4 ng/g), PFDA (3.9 ng/g), PFPeS (12.1 ng/g), PFHxS (365 ng/g), PFHpS (18.0 ng/g), PFNS (4.3 ng/g), 4:2 FTS (16.6 ng/g), 6:2 FTS (146.1 ng/g), 8:2 FTS (165.6 ng/g) and PFOSA (171.8 ng/g). Of the remaining 7 PFAS, the removal efficiency ranged between 49% and 99.9%. It appears that eBeam degradation of PFAS in soil is more effective at reduced soil moisture content.

Electron beam assistant controllable synthesis of 2D, 3D and 0D CuxO loaded on graphene for high-performance bifunctional photocatalytic and Fenton-like catalysts

Narrow wavelength response range and low utilization of light greatly limit the practical application of photocatalysts. Aiming at the insufficiency, a visible light photocatalytic and Fenton-like bifunctional catalyst based on CuxO loaded on graphene nanosheets (CuxO/GNSs) has been designed and prepared. In the synthesis process, the hydration electrons (eaq−, −2.8 V) generated by the radiolysis of water by high-energy electron beam (EB), are used as the reducing agent to reduce CuO/GNSs to CuxO/GNSs. Through adjusting the irradiation dose of EB, the concentration of eaq− in the reaction system can be easily controlled, and a series of CuxO/GNSs with different reduction degrees and morphology are prepared. When the EB irradiation dose increases from 70 to 350 kGy, the morphology of CuxO loaded on GNSs change from 2D nanosheets to 3D nanocubes, then to 0D nanodots. Through the water treatment experiments, the CuxO/GNSs prepared at 350 kGy irradiation dose (CuxO/GNS350) exhibits the best photocatalytic and Fenton-like catalytic performance among all the samples. It can be attributed to the ultrafine nanodots structure (10–15 nm) of Cu2O in CuxO/GNS350, which can shorten the distance of photogenerated charges migration to the material surface, as well as provide a wealth of active reaction sites for reactants. This work provides an efficient and eco-friendly EB assistant method to prepare CuxO/GNS with controllable size and dimensions for high performance bifunctional photocatalytic and Fenton-like catalysts.

Intrinsic Li Distribution in Layered Transition-Metal Oxides Using Low-Dose Scanning Transmission Electron Microscopy and Spectroscopy

Understanding Li distribution in layered lithium transition-metal oxide (LiTMO) cathodes in Li-ion batteries has been a major challenge at the atomic scale and nanoscale. Li is extremely difficult to study by transmission electron microscopy (TEM) because the high-energy electrons impart significant energy and cause massive migration. Here, we directly map the intrinsic spatial distribution and bonding of Li in LiNiO2-layered cathode materials using low-dose and low-loss electron energy loss spectroscopy (EELS). EELS spectra of the Li–K edge are measured simultaneously with O–K and Ni–L, M3,2 edges from layered, cation-mixed, and rock-salt phases and directly matched with atomic-resolution scanning TEM images to correlate the changes in peak intensities and positions to the stoichiometry changes with continual loss of Li and O. Changes in the Li content in the LiNiO2 particles as a function of electron beam dose are studied by sequential Li spectroscopic mapping. We show that the “intrinsic” Li distribution can be observed using a total dose of less than ∼1.5 × 108 e– nm–2 at an accelerating voltage of 80 kV. The method of nanoscale mapping of Li distribution introduced in this study is applicable to high-Ni LiTMO cathode materials (>89% of Ni) as well as LiNiO2. Further study on the extra peaks of the Li–K edge reveals that the peak at ∼59 eV is from the Li ions intercalated in between NiO2 layers barely interacting with each other with less Li K shell electrons pulled to the L shell electrons in NiO2. The results shown here provide improved low-loss TEM characterization approaches that can be used to understand the intrinsic fundamental behaviors in Li-ion batteries.

Efficient sensitizer-supported electron beam irradiation induced crosslinking of polyvinylidene fluoride for shape memory applications

Polyvinylidene fluoride (PVDF) preferentially crosslinks upon exposure to ionizing electron beam irradiation, leading to substantial changes in its physicomechanical and thermophysical properties. However, low dose electron beam irradiation produces inefficient crosslinking in pure PVDF while high dose irradiation tends to induce the concomitant process of transverse bond degradation. This has been addressed by incorporating a sensitizer into PVDF to increase crosslinking efficiency under low dose irradiation. However, conventional sensitizers typically suffer from self-polymerization and the release of toxic volatile gases at high temperature, which diminishes the crosslinking efficiency and is toxic. This issue is addressed here via a series of well-designed bismaleimide (BMI) sensitizers and incorporating these into PVDF films for facilitating chemical crosslinking reactions under low electron beam irradiation doses. Analysis indicates that the sensitizing action of the proposed BMI sensitizers may be due to the formation of transverse bonds between vinylene groups and PVDF chains. Versus conventional triallyl isocyanurate and trimethylolpropane triacrylate sensitizers, the proposed BMI sensitizers facilitate high radiation crosslinking efficiency and exhibit good compatibility. Accordingly, the proposed sensitizers leading to irradiated PVDF films with outstanding thermomechanical performance and shape memory functionality.

Analysis of carotenoids in edible flowers of Dianthus chinensis processed by ionizing radiation

The tendency to use edible flowers in gastronomy to add beauty, color, and flavor in food preparation has been increasing in recent years. Several species have active biological substances, which play an important role in health maintenance. This highly perishable food should be grown without the use of pesticides. Thus, several methods are applied to increase the shelf life of food products, as well as ensure their quality and safety. Among the treatments, the food irradiation process has proven to be an effective tool in preserving and extending the shelf life of the perishable product. Dianthus chinensis flowers, popularly known as chinese pink (cravina), belongs to the family Caryophyllaceae, are native to Asia and Europe, are widely used in culinary preparations, is also acknowledged for their bioactive components and antioxidant properties. The purpose of this study was to evaluate carotenoids in D. chinensis flowers submitted to gamma irradiation and electron beam doses of 0.5, 0.8, and 1.0 kGy. High performance liquid chromatography was used to carotenoids determination. In the specie of edible flowers analyzed it was found carotenoid lutein (4.02 to x 7.52 mg/ 100 g). In general, the lutein was higher for irradiated samples, especially those treated with 0.8 and 1.0 kGy independently of irradiation technology. Accordingly, the applied irradiation treatments seemed to represent a feasible technology to preserve the quality of edible flower petals.

Direct comparison of gamma, electron beam and X-ray irradiation doses on characteristics of low-density polyethylene, polypropylene homopolymer, polyolefin elastomer and chlorobutyl rubber medical device polymers

There is a growing need for increased efficiency in the sterilization of single use medical devices and other products that contain polymer components. Gamma radiation is widely used for devices suited for radiation sterilization; however, safety, throughput and cobalt-60 source availability are challenging the prospect of relying on gamma radiation to meet the anticipated needs of the industry. Use of electron beam (e-beam) and X-rays as alternatives to gamma for radiation sterilization have been hampered in part by a concern that these modalities may adversely affect polymer integrity and performance relative to the gamma method, for which the industry has had much more experience. To address this concern, the effects of sterilization-relevant doses of e-beam, X-ray and gamma radiation were directly compared using common medical device polymers found in two prototypical commercial devices currently sterilized using cobalt-60 gamma irradiation. The Becton, Dickinson and Company (BD) Vacutainer™ Plus tube contains low-density polyethylene and chlorobutyl rubber components, while the BD Vacutainer™ Push Button Blood Collection Set contains polypropylene homopolymer and polyolefin elastomer components. Injection-molded samples prepared from the polymers used in these products were exposed to target doses of 15, 35, 50 and 80 kGy using gamma, e-beam and X-ray radiation. Changes in coloration, tensile properties and hardness were measured for each condition, and the effects of e-beam and X-ray irradiation compared with the effects of gamma irradiation on these properties. Both e-beam and X-ray appear as viable alternatives to gamma irradiation for sterilization of the polymers tested.

Flow forming of wood irradiated with electron beam ― Molding load of irradiated wood and mechanical properties of the molded material

In the flow forming technique of wood, a wood block is flowed into metal dies to mold the material into a three-dimensional complex shape. The purpose of this study was to investigate the effect of molding load and the mechanical properties of the molded material in the case that wood as a raw material was irradiated with electron beam (EB). The EB-irradiated wood board was impregnated with thermosetting resin and was subsequently molded into the material by adding pressure and heating in a closed metal die. It was found that the molding load of the impregnated wood was decreased with increasing the EB absorbed dose. The mechanical properties of the molded material were evaluated using modulus of elasticity (MOE) and modulus of rupture (MOR) in a three-point bending test. With increasing EB dose, MOR decreased greatly, while MOE decreased slightly. The EB irradiation on raw wood made it possible to mold the material at low load, though higher dose irradiation caused larger decreases in the mechanical properties.