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Compositional analysis by RBS, XPS and EDX of ZnO:Al,Bi and ZnO:Ga,Bi thin films deposited by d.c. magnetron sputtering
摘要： Rutherford backscattering spectrometry, X-ray photoelectron and X-ray energy dispersive spectroscopies were employed to analyse Bi incorporation into ZnO:Al and ZnO:Ga transparent and electrically conductive thin films deposited by d.c. magnetron sputtering, with thickness in the range of 300–400 nm. Sputtering was performed in an argon atmosphere from two targets in confocal geometry being one composed of either ZnO:Al2O3 or ZnO:Ga2O3 composites and the other a Bi metal target. The content of bismuth dopant in the ZnO matrix was controlled by the respective target current density (JBi) in order to attain a high optical transparency (> 80%) in the visible region. For ZnO:Al,Bi films Bi content varied from 0.1 to a maximum of 1.5 at.% when varying JBi from 0.06 to 0.26 mA cm?2. However, for ZnO:Ga,Bi films, deposited in similar conditions, Bi reached a maximum overall layer content of 2.4 at.%, with a surface enrichment content that varied from 1.3 to 8.8 at.%. It was also observed that the Bi content in the topmost layers of the films is slightly depleted due to thermal evaporation upon thermal annealing in vacuum at 350 °C. It is envisaged applications for these films as transparent photoelectrodes and thermoelectric materials.
关键词： Ga,Bismuth,TCO,Doping,Thermoelectric,Al,XPS,RBS,PIXE,ZnO
更新于2025-09-23 15:23:52
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Kossel diffraction observed with X-ray color camera during PIXE of nano-scale periodic multilayer
摘要： By combining Kossel di?raction with particle induced X-ray emission, we have developed a new methodology to analyze nano-scale thin ?lms. We report the Kossel di?raction generated by irradiating Pd/Y based nano-scale periodic multilayers with 2 MeV protons. The intensity of characteristic Pd Lα X-ray emission is measured as a function of the detection angle (grazing exit). An oscillation of its intensity is observed when the detection angle varies around the Bragg angle, which corresponds to the energy of the emission and the period of the multilayer. Use of the X-ray color camera enables the whole setup to be ?xed so that no angular scan is required, greatly simplifying the experimental condition. From the features of the Kossel curves, we are able to deduce that nitrided Pd/Y multilayers exhibit much less layer intermixing than the non-nitrided multilayers. The experimental results show that it is possible to distinguish by the shape of Kossel curves of multilayers with B4C barrier layers located in di?erent interfaces. This demonstrates that Kossel di?raction is structural sensitive.
关键词： Kossel di?raction,Periodic multilayer,PIXE
更新于2025-09-23 15:21:01
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Elemental analysis of cultured pearls by PIXE
摘要： Cultured pearls are formed in pearl sacs comprising epithelial cells transplanted into mother-of-pearl. The formation mechanism is complicated and is still not fully understood. Previous studies have shown that the pearl formation is influenced by aquaculture environment and physiological activity of shellfish. The elemental compositions of seawater and freshwater pearls are significantly different. In this work, we used the particle-induced X-ray emission (PIXE) technique to perform elemental analysis of six types of pearls: ordinary and blue Akoya pearls, black-, gold-, and white-lipped oyster pearls, and freshwater Biwako pearl. We investigate the influence of trace elements in aquaculture environments on formation of mother-of-pearl or color. The Mn/Sr or Fe/Sr ratio for the freshwater pearl was found to be significantly higher than that for the seawater pearl. Comparing the sweater pearls, the gold-lipped oyster pearl has high value of Mn/Sr ratio. The Fe/Sr and Cu/Sr ratios for two Akoya pearls harvested from the Sea of Japan are relatively high compared with black-, gold-, and white-lipped oyster pearls from the South Sea.
关键词： cultured pearl,PIXE,trace element.
更新于2025-09-19 17:15:36
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Design and optimization of a laser-PIXE beamline for material science applications
摘要： Multi-MeV proton beams can be generated by irradiating thin solid foils with ultra-intense (>1018 W/cm2) short laser pulses. Several of their characteristics, such as high bunch charge and short pulse duration, make them a complementary alternative to conventional radio frequency-based accelerators. A potential material science application is the chemical analysis of cultural heritage (CH) artifacts. The complete chemistry of the bulk material (ceramics, metals) can be retrieved through sophisticated nuclear techniques such as particle-induced X-ray emission (PIXE). Recently, the use of laser-generated proton beams was introduced as diagnostics in material science (laser-PIXE or laser-driven PIXE): Coupling laser-generated proton sources to conventional beam steering devices successfully enhances the capture and transport of the laser-accelerated beam. This leads to a reduction of the high divergence and broad energy spread at the source. The design of our hybrid beamline is composed of an energy selector, followed by permanent quadrupole magnets aiming for better control and manipulation of the final proton beam parameters. This allows tailoring both, mean proton energy and spot sizes, yet keeping the system compact. We performed a theoretical study optimizing a beamline for laser-PIXE applications. Our design enables monochromatizing the beam and shaping its final spot size. We obtain spot sizes ranging between a fraction of mm up to cm scale at a fraction of nC proton charge per shot. These results pave the way for a versatile and tunable laser-PIXE at a multi-Hz repetition rate using modern commercially available laser systems.
关键词： hybrid beamline and beam manipulation,laser-PIXE,Cultural heritage,particle induced X-ray emission (PIXE),laser-driven proton acceleration,ion beam analysis
更新于2025-09-12 10:27:22
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Neural network prediction of K and L-shell X-ray production cross sections
摘要： The ionization and X-ray production cross section are fundamental parameters in elemental analysis by PIXE technique. Unfortunately no exact general analytical expression exists, from which the interest of this work. In this paper, we apply the neural network technique in the evaluation of the X-ray production cross sections. The calculations are based on Mukoyama’s PWBA data. Our results are compared with experimental data for protons and alpha particles for energies ranging from hundreds KeV to tens MeV.
关键词： PWBA,cross section,PIXE,neural network
更新于2025-09-04 15:30:14
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Standardization of Proton Induced X-Ray Emission for Analysis of Trace Elements in Thick Targets
摘要： This paper presents the standardization of Proton Induced X-rays Emission (PIXE) technique for the trace element analysis of thick standard samples. Three standard reference materials (SRMs) viz-à-vis titanium, copper and iron base alloys were used for the study due to their availability. The protons beam was accelerated up to 2.57 MeV energy by 5UDH-II tandem Pelletron accelerator and samples were irradiated at different geometry and durations. Spectrum was acquired using a multi-channel spectrum analyzer while spectrum analysis was done using a GUPIXWIN model for determination of elemental concentrations of trace elements. The obtained experimental data was compared with theoretical data and results were found in close agreement.
关键词： GUPIXWIN Software,PIXE Standardization,Trace Elements
更新于2025-09-04 15:30:14