Advanced Electron Beam Research Articles

Enhanced DNA damage induced by ultrashort electron beams in the presence of a Cu-containing porphyrin

This article presents an investigation into the interaction between ultrashort electron beams and DNA molecules. With the advent of advanced electron beam technology, the potential applications in various fields, including medicine and genetic engineering, have garnered significant attention. However, the intricate mechanisms underlying the interaction between ultrashort electron beams and DNA molecules remain largely unexplored. This study aims to bridge this gap in knowledge by obtaining experimental data. We used Cu containing water-soluble cationic 4-N meso-tetra-oxyethyl-pyridyl porphyrin. The electron beam irradiated the samples with different relative concentrations of porphyrin per base pair. It was shown that the presence of porphyrin enhances DNA stability, making it more resistant to radiation-induced damage, with the effect varying based on porphyrin concentration and irradiation dose.

Adrenaline biosensors based on r Go/Ag nanocomposites functionalized textiles using advanced electron beam irradiation technique

This study developed flexible textile biosensors based on rGO/Ag nanocomposite to detect adrenaline (epinephrine). Reduced graphene oxide (rGO) and Ag nanoparticles (NPs) were obtained in a single step using the electron-beam irradiation technique, a rapid, efficient, plain, ecofriendly, and easily scalable procedure. The nanocomposites’ properties were characterized by ultraviolet–visible-light spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Furthermore, the obtained sensors’ electrochemical behaviors of epinephrine were investigated using square wave voltammetry (SWV), linear sweep voltammetry, and differential pulse voltammetry methods. The optimum experimental conditions included pH 7, phosphate borate buffer, accumulation time of 100 s, accumulation potential of 0.4 V, and a scan rate of 100mV/s. In addition, the anodic peak currents of epinephrine by SWV were 16.33 and 13.9 µA for rGO/AgNP/cotton and rGO/AgNP/polyester, respectively. The fabricated flexible textile biosensors exhibited high sensitivity and strong catalytic activity for epinephrine detection. Under optimal testing conditions, in the range of 0.5–100.0 µL, two detection lines and a low limit of detection (LOD) of 9.73 nM (S/N = 3) for epinephrine were obtained for cotton and polyester biosensors. Two wide detection ranges were observed at 0.5–40.0 µL for cotton biosensors, whereas there was a lower LOD of 3.05 nM (S/N = 3) at 1.0–30 µL for polyester biosensors. Overall, the constructed electrode can serve as a promising analytical sensor for adrenaline determination in pharmaceutical and biological samples.

The Mathematical Model of Arc Discharge in Metal Vapors at Active Gases over Crucible for Technological Process of Electron Beam Deposition of Ceramic Coatings

The mathematical model of arc discharge in the metal vapors, propagated in the soft vacuum in the medium of active gases, is presented in this chapter. Such type of discharge is widely used in advanced electron beam technologies for obtaining the coating of new types from nanostructurized materials, especially ceramics coating.

Advanced Electron Beam (EB) Wastewater Treatment System with Low Background X-ray Intensity Generation

Electron beam wastewater treatment is a very effective method for the destruction of organic and microbiological pollutants. The technology was implemented for municipal and textile industry wastewater treatment. Availability of electron accelerators characterized with different operation parameters make the technology applicable for different end-users and also for installation in confined spaces. In such a case, the design of wastewater irradiation room has to take into account the limited space available for shielding construction, which must restrict X-ray emission. Considering construction of an irradiation room for water treatment facility, it is important to focus not only on a stream formation for irradiation to achieve the desired electron penetration, but also on the reduction in x-ray generation. In the presented work, the X-ray field was tested, using modelling and experimental methods. The final results gave an advanced solution, which can be used in the installation of wastewater treatment, ballast and other types of origin, providing low cost shield and good radiation protection measures.

Cluster ion source for external injection and high capacity filling of light elements into the relativistic heavy ion collider electron beam ion source.

An advanced Electron Beam Ion Source (EBIS) is the primary ion source to supply highly charged ion beams of different elements to the Relativistic Heavy Ion Collider (RHIC) and to the NASA Space Radiation Laboratory (NSRL). Intense beams of highly charged ions of various elements of the periodic table, ranging from helium to uranium, have been demonstrated since EBIS became operational in 2010. EBIS routinely provides ion beams to RHIC and NSRL quasisimultaneously with about 1 s switching time between different ion species. Such unique flexibility and rapid switching between ion species are based on external injection of singly charged ions into the EBIS trap either in "fast" or "slow" injection modes. At present, a Laser Ion Source (LIS) provides most of the ion species of solid materials using the "fast" injection mode into the EBIS trap and a Hollow Cathode Ion Source (HCIS) provides most of the ion species of gaseous elements using the "slow" injection mode into the EBIS trap. Gas injection into the EBIS trap is also possible and has been used but imposes some restrictions for the simultaneous generation of highly charged ions such as Au32+ ions for RHIC and ions of gaseous species for NSRL. Because light ions have relatively high velocity inside the EBIS trap, efficient injection of hydrogen and helium ions and filling of the EBIS trap to high capacity is difficult from either LIS or HCIS. To overcome this restriction and enhance EBIS operational capability, we suggest injecting beams of hydrogen and helium cluster ions into the EBIS trap. Required parameters of cluster ion beam injection into the EBIS trap are estimated, and advantages of such an injection are highlighted. A cluster ion source with required high intensity is visible and will be designed, built, optimized, and tested.

Tailoring sidewall profiles of magnetic tunnel junctions fabricated with various etching conditions

Structural and compositional characteristics of MgO-based magnetic tunnel junctions were characterized using advanced transmission electron and focused-ion beam microscopies. These junctions were fabricated from two ferromagnetic layers separated by a dielectric one and have a switchable resistance that depends upon the relative magnetizations of those two ferromagnetic layers. Certain etching conditions were used to complete the fabrication process aiming to achieve sharp-edge profiles on either side of the pillars. Controlling the edge profiles of those fabricated pillars enables to avoid shortcuts that induce magnetoresistance effect. Not only structural properties of each layer in the MgO junction are characterized, but its compositional characteristics are also explored with electron energy loss spectroscopy, this aims to elucidate the role of elements existing in the given MgO structure. Results of this work are of technological interest since they provide a better understanding in the microstructural properties of the MgO-based magnetic tunnel junctions.

Pollution from uncontrolled coal fires: Continuous gaseous emissions and nanoparticles from coal mines

In this investigation, the coal fires in different Colombian coal mines were studied using advanced electron beam and X-ray diffraction techniques. The results were compared with information from high-resolution transmission electron microscopy (HR-TEM) equipped with a dispersive X-ray detector (EDS). Amorphous phases, salammoniac, anatase, muscovite, goethite, jarosite, calcite, gypsum, kaolinite, illite, and quartz are the dominant mineral matter constituents in almost all of the coal fires, with minute quantities of native sulfur, magnetite, siderite, pyrite, pickeringite, epsomite, hexahydrite, halotrichite being present in around half of the investigated coal fire samples. Other minerals that are present in some particular samples are chlorite, ankerite, and dolomite. Fe-sulfides were also detected particularly in the pyrite-bearing coal fires, possibly indicating oxidation of the Fe-sulfides occurring with coal fires. Exhaust discharge data indicate an overall trend of reducing carbon dioxide (CO2) and carbon monoxide (CO) releases (between 1.5 and 34%) from the coal fires. This is the first report on Colombian coal fires, which would be important for different perspectives of the research in the area.

River dynamics and nanopaticles formation: A comprehensive study on the nanoparticle geochemistry of suspended sediments in the Magdalena River, Caribbean Industrial Area

The coastal zones on continental shelves are the main channels for the distribution of fluvial-sourced suspended sediments (SSs). In the current research, the monthly average amount of SS draining into the Caribbean Sea from the Magdalena River in northern Colombia was analyzed to detect nanoparticle (NPs) containing potential hazardous elements (PHEs). The ecological authorities of Colombia claimed that the climate change is the key reason behind land erosion and floods occurred in the last years; therefore, an elaborate understanding of NP dynamics between the Magdalena River body and streambed is an essential issue in SS research. In this work, the NP geochemistry of SS in the Magdalena River estuary was studied from the perspective of water quality controls on SS sorting. The morphologies and the structures of NPs (<100 nm) were examined by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and selected area electron diffraction (SAED)/micro-beam diffraction (MBD)/energy dispersive X-ray spectroscopy (EDS) techniques. The average size of NPs was found to be greater than 2 nm and Al, Ti, Fe oxides, and other hazardous elements were also detected in the SS. The obtained data confirmed that these typical categories of NPs caused the occurrence-dependent intensification of a conjugative transmission rate associated with the regulators. The advanced electron beam technique provided a clear insight into SS transportation; therefore, it could be used as an essential instrument for river supervision/dynamics.

Advanced detector signal acquisition and electron beam scanning for high resolution SEM imaging

The advancement of materials science at the mesoscale requires improvements in both sampling volumes/areas and spatial resolution in order to make statistically significant measurements of microstructures that influence higher-order material properties, such as fatigue and fracture. Therefore, SEM-based techniques have become desirable due to improvements in imaging resolution, large sample handling capability, and flexibility for in-situ instrumentation. By using fast sampling of SEM electron detector signals, intrinsic beam scanning defects have been identified that are related to the response time of the SEM electron beam deflectors and electron detectors. Mitigation of these beam scanning defects using detector sampling approaches and an adaptive model for settling time is shown to produce higher resolution SEM images, at faster image acquisition times, with a means to quantify the different response functions for various beam deflectors and detectors including those for electrons and ions.

Summary of WG7—High brightness power sources: From laser technology to beam drivers

In this paper we summarize the contributions presented during the Working Group 7 (WG7) sessions, dedicated to high brightness power sources. In this context we have tackled several topics of high relevance to novel accelerators, including laser technology for laser driven accelerators, the state of the art of high peak and average power lasers, the laser beam quality, contrast and stability. A number of novel results were presented especially in the area of laser beam characterization and control, advanced laser concepts, target control and electron beam diagnostics currently under development at a range of labs engaged in the development of advanced accelerator concepts.

Advanced Electron Beam Ion Sources (EBIS) for 2-nd generation carbon radiotherapy facilities

In this work we analyze how advanced Electron Beam Ion Sources (EBIS) can facilitate the progress of carbon therapy facilities. We will demonstrate that advanced ion sources enable operation of 2-nd generation ion beam therapy (IBT) accelerators. These new accelerator concepts with designs dedicated to IBT provide beams better suited for therapy and, are more cost efficient than contemporary IBT facilities. We will give a sort overview of the existing new IBT concepts and focus on those where ion source technology is the limiting factor. We will analyse whether this limitation can be overcome in the near future thanks to ongoing EBIS development.

Parametric study of a high current–density EBIS Charge Breeder regarding Two Stream plasma Instability (TSI)

In this paper we report on our results from the design study of an advanced Electron Beam Ion Source (EBIS) based Charge Breeder (ECB). The ECB should fulfill the requirements of the HIE-ISOLDE upgrade, and if possible be adapted for ion injection into TSR@ISOLDE, as well as serve as an early prototype of a future EURISOL ECB. Fulfilling the HIE-ISOLDE/TSR@ISOLDE specifications requires simultaneous increase in electron beam energy, current and current density in order to provide the requested beams with proper charge state, high intensity and with a specified pulse repetition rate.We have carried out a study on the technical requirements of the ECB. The obtained parameters were optimized to comply with technical limitations arising from the electron beam technology and plasma physics in an ECB.

6″ crystalline silicon solar cell with electron-beam melting-based metallurgical route

This paper presents a metallurgical route that consumes much less energy than the gasification route such as Siemens process-based photovoltaic (PV) value chain including metallurgical-grade silicon (MG-Si), solar-grade silicon (SoG-Si) purified by the metallurgical route, Czochralski (Cz) ingot growth, 6″ wafer fabrication, solar cell fabrication, and PV performance evaluation. Mono-like crystalline silicon ingot for achieving high purity was continuously cast with MG-Si for the fabrication of feedstock for Cz ingot growth through the advanced electron beam melting (EBM) system. The system was developed with the combination of vacuum refining part and directional solidification (DS) part for the purification of large amounts of MG-Si, where the two parts are connected by an overflow of Si melts to undergo continuous refining and casting processes in a chamber. To grow the mono-like crystalline Si ingot in our EBM system, a single crystalline seed was placed on the graphite dummy cylinder with DS zone. The mono-like crystalline Si ingot with high purity of >99.999% (above 5N) was blended 50–50 with undoped SoG-Si chunk for the compensation of boron dopant concentration in a crucible of Cz grower. The 156×156mm2 wafers were cut from Cz ingot grown with purity of >99.99999% (above 7N) by slurry-based multi-wire sawing and were fabricated by the conventional solar cell process. The measured photovoltaic performance recorded cell efficiency of 17.1%; hence its higher potential for application to the PV industry.

Изготовление наноустройств на установках электронно-лучевой литографии высокого разрешения

Изготовление наноустройств на установках электронно-лучевой литографии высокого разрешения

Investigation of the clinical potential of scattering foil free electron beams

Electron beam therapy has been an important radiation therapy modality for many decades. Studies have been conducted recently for more efficient and advanced delivery of electron beam radiation therapy. X-ray contamination is a common problem that exists with all of the advanced electron beam therapy techniques such as Bolus Electron conformal therapy, segmented electron conformal therapy, and modulated electron arc therapy. X-ray contamination could add some limitations to the advancement and clinical utility of those electron modalities. It was previously shown in the literature that the scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. Thus, in this work we investigate the dosimetric characteristics of scattering foil free (SFF) electron beams and the feasibility of using those beams for breast cancer boosts. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation utilizing our in-house Monte Carlo-based treatment planning system. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all patients. A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12 MeV. Flatness was greatly affected but the difference in flatness between conventional and SFF beams was much reduced for small cone sizes, which were often used clinically for breast boosts. It was found that the SFF electron beams could deliver high-quality dose distributions as conventional electron beams for boost treatments of the breast with an added advantage of a further reduced dose to the lung and the heart.

Directional Solidification Behaviors of Polycrystalline Silicon by Electron-Beam Melting

The advanced electron beam melting (EBM) system with the combination of vacuum refining and directional solidification (DS) performed the purification of large amounts of metallurgical grade silicon (MG-Si). In order to increase grain size or to align columnar grains being parallel to DS pulling direction in Si ingots, non-irradiated inner diameters in an EB pattern in the DS process were varied at a range of 5–35 mm. Average grain size increased with increasing non-irradiated inner diameter due to a smaller temperature gradient during the solidification of Si melts. However, the slope of the grain boundary inclined towards the ingot axis, which led to the formation of a triple junction in the ingot center in the case of large non-irradiated inner diameter. This happened despite there being a large temperature gradient due to the turbulent flow in the pool. This work reported that a purity of 99.8% for MG-Si was improved to above 99.999% with an ingot yield of 90% for 1 h.

Feasibility of replacing patient specific cutouts with a computer-controlled electron multileaf collimator

A motorized electron multileaf collimator (eMLC) was developed as an add-on device to the Varian linac for delivery of advanced electron beam therapy. It has previously been shown that electron beams collimated by an eMLC have very similar penumbra to those collimated by applicators and cutouts. Thus, manufacturing patient specific cutouts would no longer be necessary, resulting in the reduction of time taken in the cutout fabrication process. Moreover, cutout construction involves handling of toxic materials and exposure to toxic fumes that are usually generated during the process, while the eMLC will be a pollution-free device. However, undulation of the isodose lines is expected due to the finite size of the eMLC. Hence, the provided planned target volume (PTV) shape will not exactly follow the beam's-eye-view of the PTV, but instead will make a stepped approximation to the PTV shape. This may be a problem when the field edge is close to a critical structure. Therefore, in this study the capability of the eMLC to achieve the same clinical outcome as an applicator/cutout combination was investigated based on real patient computed tomographies (CTs). An in-house Monte Carlo based treatment planning system was used for dose calculation using ten patient CTs. For each patient, two plans were generated; one with electron beams collimated using the applicator/cutout combination; and the other plan with beams collimated by the eMLC. Treatment plan quality was compared for each patient based on dose distribution and dose–volume histogram. In order to determine the optimal position of the leaves, the impact of the different leaf positioning strategies was investigated. All plans with both eMLC and cutouts were generated such that 100% of the target volume receives at least 90% of the prescribed dose. Then the percentage difference in dose between both delivery techniques was calculated for all the cases. The difference in the dose received by 10% of the volume of the target was showing a mean percentage difference of 1.57%±1.65, while the difference in the dose received by 99% of the volume was showing a mean percentage difference of 1.08%±0.78. The mean percentage volume of Lung receiving a percentage dose equal to or greater than 20% of the prescribed dose was found to be 8.55%±7.3 and 8.67%±7 for the eMLC and applicator/cutout combination delivery methods respectively. Results have shown that target coverage and critical structure sparing can be effectively achieved by electron beams collimated with the eMLC. Positioning the eMLC leaves in such a way to avoids shielding any part of the projected treatment volume is most conservative and would be the recommended method to define the actual leaf position for the eMLC defined field. More optimal leaf positions can be achieved in shaping the same treatment field through the interplay of different leaf positioning strategies. We concluded that the eMLC represents an effective time saving and pollution-free device that can completely replace patient specific cutouts.

TU‐E‐108‐10: Investigation of the Clinical Potential of Scattering Foil Free Electron Beams

Purpose: The photon contamination is a common problem for all advanced modulated electron beam therapy techniques. The scattering foil is one of the major accelerator parts contributing to the generation of bremsstrahlung photons. This work aims to characterize the scattering foil free (SFF) beams from the Siemens Artiste accelerator and to study the feasibility of using those beams for breast cancer boost treatment utilizing our in‐house Monte Carlo based treatment planning system. Methods: Percentage depth doses and lateral profiles were measured for all available energies with the primary scattering foil removed. All beam characteristics were compared to those of the conventional electron beams. The SFF electron beams were modeled and simulated using the Monte Carlo method. CT scans of six previously treated breast patients were used for the treatment plan generation. Electron boost plans with conventional beams and the SFF beams were generated, respectively, for all the patients. Results: A significant reduction of the photon component was observed with the removal of the primary scattering foil for beam energies higher than 12MeV. Slight increase in beam energy was only noticed with the 18MeV and 21MeV beams. Ion chamber measurements showed higher dose per monitor unit especially at the higher energies. Flatness was greatly affected, however the difference in flatness between conventional and SFF beams was much reduced for small cone sizes and can be clinically insignificant for breast boosts. Removal of the secondary scattering foil could further reduce photon contamination but the beam flatness was also drastically deteriorated. Results from the electron boost plans showed similar target coverage with much reduced dose to the critical structures. Conclusion: The SFF electron beams can deliver high‐quality dose distributions as conventional electron beams for boost treatments with an added advantage of further reduced dose to the lung and heart. This work has been supported by a UICC American Cancer Society Beginning Investigators Fellowship funded by the American Cancer Society.

Characterization of the THz radiation source at the Frascati linear accelerator

The linac driven coherent THz radiation source at the SPARC-LAB test facility is able to deliver broadband THz pulses with femtosecond shaping. In addition, high peak power, narrow spectral bandwidth THz radiation can be also generated, taking advantage of advanced electron beam manipulation techniques, able to generate an adjustable train of electron bunches with a sub-picosecond length and with sub-picosecond spacing. The paper reports on the manipulation, characterization, and transport of the electron beam in the bending line transporting the beam down to the THz station, where different coherent transition radiation spectra have been measured and studied with the aim to optimize the THz radiation performances.

Bubble size and radial gas hold‐up distributions in a slurry bubble column using ultrafast electron beam X‐ray tomography

Gas hold‐up and bubble size distribution in a slurry bubble column (SBC) were measured using the advanced noninvasive ultrafast electron beam X‐ray tomography technique. Experiments have been performed in a cylindrical column (DT = 0.07 m) with air and water as the gas and liquid phase and spherical glass particles (dP = 100 μm) as solids. The effects of solid concentration (0 ≤ Cs ≤ 0.36) and superficial gas velocity (0.02 ≤ UG ≤ 0.05 m/s) on the flow structure, radial gas hold‐up profile and approximate bubble size distribution at different column heights in a SBC were studied. Bubble coalescence regime was observed with addition of solid particles; however, at higher solid concentrations, larger bubble slugs were found to break‐up. The approximate bubble size distribution and radial gas hold‐up was found to be dependent on UG and Cs. The average bubble diameter calculated from the approximate bubble size distribution was increasing with increase of UG. The average gas hold‐up was calculated as a function of UG and agrees satisfactorily with previously published findings. The average gas hold‐up was also predicted as a function of Cs and agrees well for low Cs and disagrees for high Cs with findings of previous literature. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1709–1722, 2013