Showing papers in "Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms in 2021"

On the use of SRIM for calculating vacancy production: Quick calculation and full-cascade options

Abstract: The vacancy production behavior for a broad range of incident ion-target combinations were examined by using both the full cascade (F-C) and quick calculation of damage (Q-C) options of Stopping and Range of Ions in Matter (SRIM-2013) code. Vacancy production for each option was evaluated using both the convenient vacancy text file in SRIM, and by manual manipulation of the energy transfer, ionization, and phonon text file data to calculate the depth-dependent damage energy for the Norgett-Robinson-Torrens (NRT) defect production model. The F-C vacancy text file method was observed to overpredict vacancy production by a factor of ~1.1 to 4 times when compared to values calculated using the F-C damage energy method or either of the SRIM Q-C methods. Based on our extensive data set obtained for 142 unique bombarding ion-target combinations, we show that the SRIM F-C vacancy text file method should not be used for vacancy production calculations. This error appears to be due to mischaracterization within the SRIM F-C option of some near-threshold replacement events as vacancies instead of replacements. Use of the latest SRIM stopping powers in the SRIM F-C approach provides a better calculation of electronic and nuclear stopping compared to the Lindhard stopping power analytical approximation used to calculate the damage energy of recoil atoms in the SRIM Q-C option, and therefore SRIM F-C approach is deemed to provide the best accuracy for vacancy production (within the binary collision approximation) as long as the damage energy method is used. Alternately, the SRIM Q-C option using either the vacancy.txt or damage energy method provides relatively fast calculation speeds with moderate quantitative differences from the F-C damage energy results (~0 to ~ 30% for the investigated ion-target cases).

Standard operation procedures and performance of the MICADAS radiocarbon laboratory at Alfred Wegener Institute (AWI), Germany

Abstract: The radiocarbon analysis laboratory at Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) is equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) The laboratory provides routine 14C analyses on bulk organic matter, plant fragments, dissolved and particulate organic matter, individual molecular lipids, and carbonate (micro-) fossils with the aim to foster international research efforts in vulnerable high latitudes The AWI MICADAS allows AMS 14C analysis on graphite targets as well as on CO2 samples via gas injection into the hybrid ion source The laboratory thus provides reliable datasets even if only small amounts of sample material are available, a problem often encountered in polar research Here we describe the standard operation procedures and sample preparation methods employed, and demonstrate the instrument performance and data quality based on repeat analysis of international reference materials

The first experimental results from the 04BM (PEEM/XAS) beamline at Solaris

Abstract: The spectroscopy using synchrotron radiation is the advanced tool for materials characterization. In the current work we are reporting recent activity in this research field implemented at the 04BM (PEEM/XAS) beamline of the National Synchrotron Radiation Centre SOLARIS in Krakow, Poland. The beamline is designed to cover wide energy range of soft X-rays, which is well suited for a broad range of applications, including surface physics, material science and magnetism. The comparison of the experimental parameters and selected examples of the results achieved on the PEEM and XAS end stations is demonstrated.

Geant4 physics processes for microdosimetry and secondary electron emission simulation: Extension of MicroElec to very low energies and 11 materials (C, Al, Si, Ti, Ni, Cu, Ge, Ag, W, Kapton and SiO2)

Abstract: Several improvements are added to the MicroElec extension of Geant4 in order to track very low energy electrons, protons and ions in different materials. The interaction processes for ions and protons are extended down to 1 keV/nucleon, and to a few eVs for electrons, corresponding to the electron affinity or work-function of the selected material. Surface interaction processes for electrons are added, along with electron–phonon interactions for SiO2. The models are validated for silicon and several new materials (C, Al, Ti, Ni, Cu, Ge, Ag, W, SiO2 and Kapton), which significantly broadens the capabilities of MicroElec. Developed for microdosimetry simulation, the module can now also be used for secondary electron emission applications.

Effect of pulsed electron beam treatment on microstructure and functional properties of Al-5.4Si-1.3Cu alloy

Abstract: The effect of pulsed electron beam treatment (density of energy 10, 30, and 50 J/cm2 and pulse times 50 and 200 µs) on the microstructure and functional properties of the Al-5.4Si-1.3Cu alloy is traced via exploring its microhardness, wear resistance and microstructure. The research pointed out the wear resistance of the alloy irradiated with pulsed electron beam to be 197% higher than the same characteristic of the untreated material. A maximal microhardness increase was recorded for following electron beam treatment parameters: 30 J/cm2, 200 µs and 50 J/cm2, 50 µs; the values of microhardness were as high as 860 MPa and 950 MPa, respectively. Key factors responsible for better wear resistance and higher microhardness in the samples treated with a pulsed electron beam were suggested to be silicon and intermetallic compounds, dissolving in the molten surface, a cellular nano-dimensional structure, resulting from rapid solidification, and nano-dimensional particles of silicon and multi-element compounds.

Combining X-ray Nano Tomography with focused ion beam serial section imaging — Application of correlative tomography to integrated circuits

Abstract: In this research we show the combination of two sub-micrometer imaging techniques, namely focused ion beam (FIB) and scanning electron microscope (SEM)-based X-ray nano tomography, on the exact same sample, a fragment of a central processing unit (CPU). Based on its three-dimensional structure, we compare the volumetric measurement results in terms of scanned volume, spatial resolution, visible details, and artifacts. For comparability reasons we limit the acquisition time to 24 h for both imaging modalities. By this comparison we evaluate the capability of our self-developed laboratory nano-computed tomography system (XRM-II nano-CT) as its performance and usability was increased by the recent upgrades. The nano-computed tomography (nano-CT) offers a 12 times larger scanned sample volume than the FIB tomography on the one hand, but a lower volumetric resolution combined with a factor of 5 lower sampling on the other. The main artifacts of the nano-CT are blurred structures caused by incomplete alignment during the reconstruction process, while in the FIB tomography curtain artifacts lead to distorted structures in the reconstructed volume. We give an outlook to combine the benefits of the two methods, where the nano-CT is used as a navigational scan for the FIB tomography to achieve the best resolution on a given part of a sample.

Photonuclear production of the medical isotope 67Cu

Abstract: We studied the production of 67Cu medical radioisotope by irradiating Zn targets of natural isotopic composition by bremsstrahlung photons with endpoint energies of 30 and 40 MeV. Cross-sections per equivalent quantum of 67Cu, 64Cu, 62Zn, 63Zn, 65Zn, and 69mZn activation products were measured. The specific activities of 67Cu were found to be 2.04 and 4.78 µCi/(µA∙h∙g) at the end of the bombardment for 30 and 40 MeV bremsstrahlung maximum energies, respectively.

Effect of electron beam energy densities on the surface morphology and tensile property of additively manufactured Al-Mg alloy

Abstract: Al-Mg alloys samples, after wire arc additive manufacturing based on cold metal transfer, have uneven microstructure, heterogeneous distribution of precipitate and elements, and even nonuniformity mechanical properties. Electron beam surface treatment (EBST) can effectively improve this phenomenon to some degree. In this study, the equipment of SOLO automatic with the electron beam is firstly adopted to develop surface treatment on wire-arc-additive- manufacturing Al-Mg specimens. Three electron beam energy densities (5, 10, 15 J/cm2) were set to investigate the effect of electron beam densities on surface microstructure, phase composition, elements distribution and tensile property of Al-Mg samples. As the irritation energy density increasing, the clarity of grain boundaries was heightened, the element Mg was evaporated furtherly and the thickness of the modification layer increased. Whereas, the surface microstructure morphology is relatively even and extending in the depth of intergranular cracks was prevented when the EBED is 10 J/cm2. Different EBST processes did not affect the phase composition of WAAM-CMT fabricated Al-Mg samples. However, the crystallization and tensile strength of Al-Mg alloy are optimum at the condition EBED = 10 J/cm2.

Estimation of Ag coating thickness by different methods using a handheld XRF instrument

Abstract: Precious objects are often made from a thin layer of metal (gold or silver) superimposed on another metal or alloy. Non-invasive XRF analysis is widely used on these objects to determine the composition and thickness of the surface layer. Here, silver surface thickness of two-layered metal samples using an ED-XRF handheld spectrometer is estimated by different methods whose results are compared. These methods involved the relationships between the intensities of the characteristic lines of Kα, Kβ, Lα and Lβ of Ag and of elements present in the substrate (Cu, Fe, Pb) and some of their combinations, as well as the PLS regression. Reference layers were used to derive the calibration curves of each methodology. PLS method was the most accurate, but the other methods were also found suitable for the purpose. Applications have been successfully made on an ancient Roman coin and a modern silver-plated object.

The features of the structural state and phase composition of the surface layer of aluminum alloy Al-Mg-Cu-Zn-Zr irradiated by the high current electron beam

Abstract: The structural and phase changes in the surface layer of the 1933 aluminum alloy caused by the irradiation of a high-current relativistic electron beam are studied. The impact of the electron beam leads to the formation of a remelted surface layer with surface relief and microcracks. The structural phase state of this layer is determined by the complex impact of the electron beam and the kinetics of melt crystallization under ultrafast cooling. Via X-ray diffraction studies and the results of energy dispersive X-ray microanalysis it became possible to make a conclusion that submicron sizes of magnesium oxide are present in the remelted layer. MgO inclusions are distributed homogeneously in the remelted layer. The presence of MgO inclusions leads to hardening of the surface layer of the alloy. The nature of formation of MgO during the impact of a pulsed electron beam are discussed

Electron transport in DNA bases: An extension of the Geant4-DNA Monte Carlo toolkit

Abstract: The purpose of this work is to extend the Geant4-DNA Monte Carlo toolkit to include electron interactions with the four DNA bases using a set of cross sections recently implemented in Geant-DNA CPA100 models and available for liquid water. Electron interaction cross sections for elastic scattering, ionisation, and electronic excitation were calculated in the four DNA bases adenine, thymine, guanine and cytosine. The electron energy range is extended to include relativistic electrons. Elastic scattering cross sections were calculated using the independent atom model with amplitude derived from ELSEPA code. Relativistic Binary Encounter Bethe Vriens model was used to calculate ionisation cross sections. The electronic excitation cross sections calculations were based on the water cross sections following the same strategy used in CPA100 code. These were implemented within the Geant4-DNA option6 physics constructor to extend its capability of tracking electrons in DNA material in addition to liquid water. Since DNA nucleobases have different molecular structure than water it is important to perform more accurate simulations especially because DNA is considered the most radiosensitive structure in cells. Differential and integrated cross sections calculations were in good agreement with data from the literature for all DNA bases. Stopping power, range and inelastic mean free path calculations in the four DNA bases using this new extension of Geant4-DNA option6 are in good agreement with calculations done by other studies, especially for high energy electrons. Some deviations are shown at the low electron energy range, which could be attributed to the different interaction models. Comparison with water simulations shows obvious difference which emphasizes the need to include DNA bases cross sections in track structure codes for better estimation of radiation effects on biological material.

Thickness determination of the gilding on brass materials by XRF technique

Abstract: The gold coating layer of the gold-plated brass objects was estimated using calibration curves obtained with a handheld X-ray fluorescence spectrometer (XRF). Calibration curves were obtained using reference materials (Au and brass) and intensity ratios of the X-ray fluorescence peaks generated in both the gold coating and the brass substrate. In addition, a calibration was also performed with the PLS (Partial Least Squares) multivariate analysis method. Good agreement was obtained by comparing the results of the different methods. The calibrations were successfully applied to gold-plated brass jewels and samples.

Measurement of the 7Li(p,p'γ)7Li reaction cross-section and 478 keV photon yield from a thick lithium target at proton energies from 0.65 MeV to 2.225 MeV

Abstract: Reliable data on 7Li(p,p'γ)7Li reaction cross section and photon yield from a thick lithium target are important for many applications including boron neutron capture therapy of malignant tumors. Experimental data on cross section differ greatly from one author to another; experimental data on photon yield are extremely scarce. Measurements of the reaction cross section and photon yield were carried out at the accelerator-based neutron source at the Budker Institute of Nuclear Physics (Novosibirsk, Russia) using a NaI and HPGe γ-ray spectrometers. The 7Li(p,p'γ)7Li reaction cross section and 478 keV photon yield from a thick lithium target at proton energies from 0.65 MeV to 2.225 MeV have been measured with high accuracy. The data obtained are presented in the form of tables.

Bunching and chopping for tandem accelerators. Part II: Chopping

Abstract: A chopping system of a tandem accelerator based on two pairs of parallel plates is investigated. The first chopper operating at 37.5 MHz cuts off the tails of the bunched beam and the second, at a lower frequency of 4.6875 MHz, eliminates the satellite low intensity pulses. The experimental procedures for measurement of the performance of a chopping system including a Beam Profile Monitor (BPM) technique and a pulsed beam diagnostic monitor are described. The results of simulations and experimental observations are presented. An analytical technique to reconstruct the real profile of deflected beams from the profile measured with a BPM is discussed in detail. Theoretical and experimental data on the chopper scanning window are presented. An analyses of the factors limiting the chopping system performance is conducted and technical solutions to overcome it are discussed.

Synergetic effects of 1 MeV electron irradiation on the surface erosion in polyimide by atomic oxygen

Abstract: Erosion studies of polyimide, exposed to high energy electrons and atomic oxygen, is necessary in view of its application in space vehicles Here we present the erosion studies and degradation characteristics of polyimide after its sequential exposure to 1 MeV pulsed electron beam from Microtron accelerator and ~12 eV oxygen ions from a plasma reactor in the laboratory The fluence of electrons was varied from 5 × 1014 to 20 × 1015 electrons/cm2 and that of oxygen ions from ~5 × 1016 to 2 × 1017 ions cm−2 The post irradiated and virgin polyimide samples were characterized by gravimetric analysis and contact-angle measurements The morphological and spectroscopic information were obtained with Scanning Electron Microscopy, Fourier Transform Infra-Red spectroscopy, and photo-absorption spectroscopy The erosion yield, surface wettability and the surface roughness were seen to be much higher when exposed to both the radiations as compared to either of them, reflecting the synergetic effects

An accelerator facility for intermediate energy proton irradiation and testing of nuclear materials

Abstract: The bulk irradiation of materials with 10–30 MeV protons promises to advance the study of radiation damage for fission and fusion power plants. Intermediate energy proton beams can now be dedicated to materials irradiation within university-scale laboratories. This paper describes the first such facility, with an Ionetix ION-12SC cyclotron producing 12 MeV proton beams. Samples are mm-scale tensile specimens with thicknesses up to 300 μ m, mounted to a cooled beam target with control over temperature. A specialized tensile tester for radioactive specimens at high temperature ( 500 + °C) and/or vacuum represents the conditions in fission and fusion systems, while a digital image correlation system remotely measures strain. Overall, the facility provides university-scale irradiation and testing capability with intermediate energy protons to complement traditional in-core fission reactor and micro-scale ion irradiation. This facility demonstrates that bulk proton irradiation is a scalable and effective approach for nuclear materials research, down-selection, and qualification.

Thermoluminescence glow curve analysis and evaluation of trapping parameters of dysprosium doped lanthanum calcium borate La2CaB10O19

Abstract: The present work elucidates thermoluminescence study of Dy activated lanthanum calcium borate (La2CaB10O19) phosphors and determination of trapping parameters. Two glow curves located at 132 and 295 °C were observed and showed a linear TL response. The kinetic parameters of the glow peaks were evaluated using variable heating rate, repeated initial rise method and Computerized Glow Curve Deconvolution. Analysis of the main dosimetric peaks reveals that the values of the activation energy and pre-exponential factor are found to be 0.78–1.145 eV and 8.59 × 109–8.44 × 1011 s−1, respectively. The sample doped with 1% Dy3+ exhibits a good stability for the reusability. Besides, the found results indicate that the temperature maximum shifts to the higher temperature side as the heating rate increases. Contrary to previously expressed theoretical expectations, anomalous heating rate dependence was observed in Dy3+ doped La2CaB10O19 sample and a semi-localized transition model explaining the anomalous heating rate effect was employed.

Ion-optical developments tailored for experiments with the Super-FRS at FAIR

Abstract: The future Super-FRS separator-spectrometer at FAIR will provide rare-isotope beams for key experiments in nuclear structure, astrophysics and nuclear reactions. The Super-FRS will use large-aperture magnets, which is important for the acceptance of nuclear reaction products with a large transverse and longitudinal emittance. In the standard ion-optical separator mode, magnetic rigidity analysis in combination with atomic energy-loss will be performed for clean isotopic spatial separation, once in the Pre-Separator and second in the Main-Separator. New ion-optical developments, prepared for different categories of experiments, are presented in this article. The operating modes described in the early publications of the project are updated in the first part of the paper. In the second part, special ion-optical modes mainly for the experiments of the Super-FRS Experiment Collaboration are discussed. This collaboration is the succession of the FRS Collaboration which has concentrated on separator-spectrometer experiments with the present facility at GSI since 1990.

Relativistic Abrasion–Ablation De-excitation Fragmentation (RAADFRG) model

Abstract: Astronauts are exposed to ionizing radiation that may pose significant health risks from missions to low Earth orbit (LEO) and beyond. The National Aeronautics and Space Administration (NASA) uses the deterministic radiation transport code, High charge (Z) and Energy TRaNsport (HZETRN), to estimate particle fluxes inside shielded vehicles to evaluate risk of radiation exposure to crew members. Highly efficient radiation transport algorithms and cross section models are needed to perform calculations in realistic vehicles with complex geometrical configurations. The HZETRN code uses the NUClear FRaGmentation (NUCFRG) model to evaluate fragmentation cross section products from nucleus–nucleus collisions. Although highly efficient, the NUCFRG model has some limitations that are based on its unique implementation of the abrasion–ablation formalism. NUCFRG performs well in predicting fragmentation cross sections on the average when compared to experimental data; however, even–odd nuclear structure effects observed in laboratory measurements are absent. The aim of the present work is to formulate a self-consistent theory that produces accurate nuclear fragmentation cross sections while maintaining numerical efficiency. To that end, the Relativistic Abrasion–Ablation FRaGmentation (RAADFRG) model has been developed. The theoretical framework for nuclear interaction is multiple scattering theory (MST), where relativistic kinematics may be included in the momentum–space representation of the Lippmann–Schwinger equation. The nuclear abrasion model employs the Eikonal (Eik) approximation and is used to predict prefragment cross sections. A novel approach is utilized for the excitation energy of prefragment, where in addition to differences of binding energies between two nuclei, energy is transferred to the prefragment from subsequent multiple scattering of abraded nucleons with the spectator nucleon constituents of the prefragment. Next, the excited prefragment liberates particles through the nuclear ablation process, and a nuclear coalescence model that forms aggregate particles for each prefragment channel is included in the yield. The ElectroMagnetic Dissociation FRaGmentation (EMDFRG) model is also included for peripheral interactions that stimulates particle emission via nuclear-photon field interactions. When compared to NUCFRG3, uncertainty quantification analysis shows that RAADFRG is better able to predict experimental nuclear fragmentation cross sections. RAADFRG is also shown to produce the even–odd nuclear structure effects, which is achieved by modification of isospin pairing correction in the prefragment excitation energy model.

Characterization of microstructures and mechanical property of Fe-ion-irradiated China A508-3 steel

Abstract: Irradiation hardening of Chinese reactor pressure vessel steel A508-3 was evaluated by transmission electron microscopy and nanoindentation technique. The specimens were irradiated with 3.5 MeV 56Fe13+ ions to 1.0, 5.0, 15.0 and 20.0 dpa with a damage rate of 1.2 × 10-4 dpa/s at room temperature. The irradiation microsturcture observed by TEM revealed that the mean size and number density of the dislocation loops were both increased with the damage dose. Hardening phenomenon was observable after irradiation and a power law relationship of the bulk equivalent hardness with the damage level was proposed. The dispersed barrier hardening model was used to numerically calculate the correlation between the irradiation microstructure and hardening. The results show that the calculated hardness values are basically consistent with the experimental data at 5 dpa, but there is a certain deviation was found above 15 dpa, which may be caused by the formation of solute clusters.

Luminescence of Ce3+ and Li+ co-doped MgO synthesized using solid-state reaction method

Abstract: MgO:Ce3+,Li+ was synthesized by the solid-state reaction (SSR) method and its luminescence properties were investigated. The X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were used for the structure analysis. The luminescence properties were studied using thermoluminescence (TL), photoluminescence (PL), and radioluminescence (RL) techniques. The step annealing experiment was conducted to find the preheating temperature. The dose–response features as a function of β-ray exposure extended from 0.2 Gy to 2 kGy were investigated. The kinetic parameters such as the activation energy (Ea), frequency factors, and order of kinetics of MgO:Ce3+,Li+ were found using the computerized glow curve deconvolution (CGCD), variable heating rate (VHR) methods, and Tm-Tstop method in combination with the Initial Rise (IR) method. The experimental results of the TL, PL, and RL analyses can serve for a better understanding of the luminescent mechanism in Ce3+ and Li+ activated MgO for the potential use of designing phosphor as a dosimeter and optical ceramic material.

Recent developments in the AMS system at the Nuclear Science Laboratory: Impacts on radionuclide sensitivities and current capabilities

Abstract: In recent years, the AMS system at the Nuclear Science Laboratory of the University of Notre Dame has introduced a series of upgrades which have dramatically increased the capabilities for the measurement of trace radionuclides. These upgrades have solved issues with isotopic selectivity in the injection system, allowed for the measurement of heavier radionuclides, and improved the quality of both ion beams and the data obtained with them. The specifics of the installed equipment, as well as preliminary results on isotopic sensitivities for previously measured and newly-developed radionuclides, are discussed. Finally, the impacts on the development of planned radionuclide measurements in the future, including measurements of the actinides, will be mentioned.

The research on optical radiation in the collisions of low energy, highly charged Xeq+ ions with MgOAl2O3 surfaces

Abstract: In this work, the optical spectra emitted from the magnesia-alumina spinel (MgOAl2O3) surfaces induced by low energy, highly charged Xeq+ (6 ≤ q ≤ 20) ions were measured. In the collisions, the excitation process of sputtered atoms is discussed. In the analysis, a special attention was given to spectral composition of the optical radiation, dependences of lines intensity on projectile charge state (projectile potential energy), relative intensities of different lines, in which mainly present three features: (a) the results do not appear the spectral line of O particle. (b) there were no apparent increases in the photon yields of atomic Mg and Al lines with the increase of projectile charge state. (c) the ratios of spectral lines Al I 309.27 nm to Al I 396.41 nm of excited Al atoms ejected from the surface of insulator MgOAl2O3 increased with the increasing projectile potential energy, and both of the ratios of spectral lines Mg II 280.40 nm to Mg I 285.42 nm and Mg II 279.73 nm to Mg I 383.37, 383.98 nm increased with projectile potential energy increase.

Effect of thermal annealing on SHI irradiated indium implanted glassy carbon

Abstract: The effects of swift heavy ion irradiation on implanted glassy carbon, the modification and migration of indium after vacuum annealing have been investigated. Radiation damage was introduced to the glassy carbon substrates after room temperature implantation by 360 keV indium ions to a fluence of 2.0 × 1016 ions/cm 2. The implanted samples were subsequently irradiated at room temperature by swift heavy ions (167 MeV Xe 26+ ions). Isochronal annealing of both sets of samples from 200 to 600 °C for 1 h was performed in vacuum. The SHI irradiation, induced some restructuring in the damaged glassy carbon substrates. Vacuum annealing of the SHI irradiated samples gave rise to recovery and the diffusion of implanted In which was different from that of the as-implanted sample. Higher retention was observed at each temperature for SHI irradiated samples compared to as-implanted samples. The diffusion coefficients of the SHI irradiated samples were lower than for un-irradiated sample.

Assessment of metallic nanoparticles as radioenhancers in gastric cancer therapy by Geant4 simulation and local effect model

Abstract: Gastric cancer ranks as one of the most common and poor prognosis human malignancies. We investigated the radioenhancer effects of gold, silver, platinum, bismuth, iron oxide, titanium oxide and germanium nanoparticles on simulated gastric adenocarcinoma cells, irradiated with 6 MV X-rays in presence of 0.05 µM, 0.25 µM and 0.5 µM homogeneous distributed metal nanoparticles throughout the cell, including the nucleus, cytoplasm and extracellular matrix using Geant4 Monte Carlo simulation along with LEM radiobiological model. The survival reduction coefficient was obtained 0.5 for light nanoparticles including 0.5 μM titanium oxide, iron oxide and germanium and also 0.3–0.1 for heavy nanoparticles including 0.5 μM gold, silver, bismuth and platinum. Nanoparticle-mediated Enhancement Ratio for 0.5 μM internuclear Gold, Silver, Bismuth, Germanium, Platinum, Iron oxide and Titanium oxide nanoparticles was calculated to 0.10, 0.27, 0.26, 0.47, 0.09, 0.50, and 0.58, respectively. Radiosensitization by NPs may enhance therapeutic efficacy of gastric adenocarcinoma.

Effect of high temperature annealing and SHI irradiation on the migration behaviour of Xe implanted into glassy carbon

Abstract: The effect of high temperature annealing and swift heavy ion irradiation (SHI) on the migration behaviour of xenon (Xe) implanted into glassy carbon (GC) have been investigated. GC substrates were implanted with 200 keV Xe ions to a fluence of 1 × 1016 cm−2 at room temperature. Some of the implanted samples were irradiated with 167 MeV Xe+26 ions to a fluence of 1 × 1014 cm−2 at room temperature. Both the as-implanted and implanted then irradiated were annealed in a vacuum at temperatures ranging from 1000 °C to 1500 °C in steps of 100 °C for 5 h. The RBS depth profiles showed that the implanted xenon migrates mostly into the bulk of the GC with the formation of a bimodal distribution. Microstructural changes in the glassy carbon substrate due to Xe bombardment and annealing were monitored using Raman spectroscopy. Raman results showed that swift heavy ion (SHI) irradiation caused some recrystallization in the amorphous region.

Study on surface modification of silicone rubber for composite insulator by electron beam irradiation

Abstract: In order to improve the outdoor service life of composite insulators, the effect of electron beam irradiation on SIR is studied. In this paper, the silicone rubber was treated by two different doses of electron beam irradiation, and the accelerated aging test of 1000 h high temperature, high humidity and strong sunlight was carried out in the multi factor aging test chamber. At the same time, the physical and chemical properties such as physical tensile properties, hydrophobicity, optical microscope, scanning electron microscope (SEM), Attenuated Total internal Reflection Fourier Transform Infrared Spectrometer(ATR-FTIR) and crosslinking density were analyzed. The results showed that after low electron beam irradiation dose (40 kGy) treatment, the crosslinking density of silicone rubber increased by 8.8 times, and after 1000 h aging treatment, the crosslinking density of low irradiated(40 kGy) silicone rubber is still 6 times higher than that of unirradiated silicone rubber. Based on the analysis of the test results, the surface modification mechanism of silicone rubber under electron beam irradiation and aging is proposed. The research observation results demonstrate the influence of electron beam irradiation and aging on silicone rubber. Related research provides a novel idea for improving the service life of insulators.

The SPES target production and characterization

Abstract: The target sits at the core of each facility for the production of radioactive ion beams for nuclear physics research. The materials which constitutes it must withstand extremes conditions of temperature and pressure, being bombarded by intense beams of light particles for several days. This is particularly important in high-power facilities such as SPES (Selective Production of Exotic Species) in which the targets are subjected to strong thermal gradients. Accurate choice and design of materials are therefore crucial. On recent years, several studies have been carried out in the framework of the SPES target research and development. An overview of recently exploited production techniques and a selection of synthesized materials are presented.

TEM analysis of radiation effects in ODS steels induced by swift heavy ions

Abstract: Oxide dispersion strengthened steels ODS Eurofer and ODS 13.5Cr-0.3Ti were irradiated with 945 MeV Au ions and 167 MeV Xe ions at room temperature. Beam-induced microstructural changes were analyzed by high-resolution transmission electron microscopy in the region of maximum electronic energy loss of 55 and 30 keV/nm, respectively. In both ODS steels, an increase in the fraction of small oxide inclusions (

PHELIX – A new soft X-ray spectroscopy beamline at SOLARIS synchrotron

Abstract: PHELIX is a new beamline at National Synchrotron Radiation Centre SOLARIS in Krakow using soft X-rays. The source of radiation is an Elliptically Polarizing Undulator APPLE II type with permanent magnets producing a variable polarization of light. The maximum size of the excited area on the sample will be smaller than 100 µm × 100 µm with the resolving power (RP) of at least 10 000 over the entire energy range (available range 50–1500 eV) and for all polarizations. The PHELIX end-station enables a wide range of spectroscopic methods including angle integrated and angle resolved photoemission, spin resolved photoemission and x-ray absorption studies under UHV conditions. The VLEED spin detector allows to determine all three components of photoelectron spin. The beamline is perfectly suited for investigations of new electronic materials, topological insulators, thin films and multilayers systems, surface of bulk compounds, surface magnetism, spin polarized surface states, biomaterials, etc.