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In this work, elemental composition of 18 metallic objects belonging to the Bronze Age found at the Kalate Shoori site in Neyshabur, northeastern Iran, is investigated using micro-PIXE technique. The aim of the analysis is to identify the type of alloys employed in the fabrication of the investigated objects based on their elemental composition and to measure their contents of trace elements. The results of the micro-PIXE analyses indicate that the investigated objects could be categorized in two main groups: The objects of the 1st group (11 objects) are made of copper–silver alloys in which copper content varies within 30–60 wt% while silver content varies within 25–40 wt%. The objects of the 2nd group (7 objects) are made of nearly pure copper with copper content varying within 85–97 wt%. Though all the investigated metallic objects are found in the Bronze Age layers of the Kalate Shoori site, amazingly, no traces of tin were observed in their elemental composition. The measured impurities in the investigated objects could be either due to the raw materials and minerals used in the extraction of copper and silver or due to the soil surrounding the buried objects. Examination of trace elements contents in the investigated objects reveal that objects with the base of copper–silver alloys (i.e., objects of the 1st group) were all fabricated from the same raw materials, while objects with the base of nearly pure copper (i.e., objects of the 2nd group) were fabricated from different mineral materials with either no arsenic content or with varying arsenic contents of more than 1.5 wt%. Comparison of the results of this work with the published data in the literature indicates that similar samples with the base of copper–silver alloys belonging to Bronze Age have already been found in Altin Tepe, Turkmenistan. It could then be concluded that similar techniques might have been employed in the two regions. Moreover, archeological findings at the Kalate Shoori site reveal that there should be cultural and commercial exchanges between this region and the Central Asia. [ABSTRACT FROM AUTHOR]

• The calculations of the structural, electronic, and magnetic properties of new full Heusler alloys Co 2 ZrZ (Z = Pb, Bi, As) were performed. • The most stable structure of these compounds is Cu 2 MnAl with the L2 1 structure. • The majority and minority of DOS show that the Co 2 ZrPb compound has half-metallic nature with a band gap of 0.33 eV. • The band structure and DOS of Co 2 ZrBi and Co 2 ZrAs compounds exhibit ferromagnetic metallic nature of alloys. In this paper, the calculations of the structural, electronic, and magnetic properties of new full Heusler Co 2 ZrZ (Z = Pb, Bi, As) alloys were investigated within the framework of the density functional theory (DFT). Calculations were performed using the Quantum-Espresso package and ultrasoft pseudopotential, based on generalized-gradient approximation (GGA) as the exchange–correlation potential. Using ab initio calculations, properties such as equilibrium lattice constants (a 0), bulk modulus (B), electronic band structures, majority and minority of density of states (DOS), as well as the total and atomic magnetic moments of these new compounds were calculated. The results show that the most stable structure of these compounds is the Cu 2 MnAl phase with a L2 1 crystal structure. The calculation of the electronic band structure and the majority and minority of DOS show that the Co 2 ZrPb compound has half-metallic nature with a band gap of 0.33eV. However, based on the band structure and total and partial DOS, the Co 2 ZrBi and Co 2 ZrAs compounds exhibit ferromagnetic metallic nature. In addition, the calculation of the magnetic properties indicates that the Co 2 ZrPb has a total magnetic moment of 2µ B , which follows the Slater-Pauling (SP) rule. [ABSTRACT FROM AUTHOR]

Abstract: Segregation of implanted As during steam oxidation of Si wafers is shown to result in a highly enriched, thin layer of As at the interface between the oxide and the underlying Si. Also, the oxidation rate was found to increase by as much as a factor of ∼2 depending on the depth distribution and fluence of the implanted As impurity. The thin As layer collected at the interface can be used in the design of very shallow junctions. This mechanism enables the formation of a narrow, degenerately doped layer of Si, which can be tailored to have a thickness of only few monolayers depending on the fluence of the implantation used. [Copyright &y& Elsevier]

Thirteen historical Iranian manuscripts belonging to the Qajar dynasty (18th–19th Century BC) were investigated by micro-PIXE technique using Van de Graaff accelerator in the Nuclear Science & Technology Research Institute in Iran. The aim of the present work has mainly been to determine the elemental composition of different inks and papers. In addition, the effects due to the variation of thickness and texture of the paper were simultaneously measured with the off-axis STIM technique. Elemental maps by micro-PIXE were compared to photographs taken in visible light. [ABSTRACT FROM AUTHOR]

Abstract We report on formation of epi-layer of Si x Ge 1-x by taking standard procedure in CMOS technology. The competitive process of solid solubility of Ge dopant into Si and SiO 2 is the key to engineer atomically sharp, low defect very thin epitaxial layer at the interface of oxide-Si. Oxidation time process was used to control the distribution of the doped Ge ions at the interface of Si with oxide and in the oxide layer. Implanted samples (35 keV and 1 × 1016 Ge+/cm2) were oxidized at 1050 °C for 30–90 min. RBS-Channeling analysis shows two separate peaks of Ge corresponds to different depths after oxidation. Corroborate with high resolution microscopy and elemental analysis, we determined the first peak as enriched layer of Si x Ge 1-x at the interface of SiO 2 Si. Less than 10 nm epitaxially grown interfacial layer is very low in defects, and Ge ions are fully substituted into the host lattice. The second peak originated from diffusion of Ge into SiO 2 resulted in a segregated layer containing Ge in oxide film. Technological demand on forming Si x Ge 1-x layer for CMOS application through standard routes is what we address in this research. Highlights • Ge implantation and dry oxidation were used to form very thin mixed Si x Ge 1-x layer. • A rich Ge layer was formed after dry oxidation at 1050 °C. • Very thin Si x Ge 1-x layer is in epitaxial relation to the silicon substrate. • Some Ge ions are segregated in top oxide layer. [ABSTRACT FROM AUTHOR]

Abstract: Porous silicon (PS) is widely utilized in gas sensors. Palladium is a good choice to sensitize the surface of PS to hydrogen. Ideally for highest sensitivity of the sensor, all the pores of PS should be completely covered with palladium. Rutherford backscattering spectroscopy (RBS) technique is routinely used to determine depth profile of elements in thin layers. By using microbeam analysis as a complementary technique, we clearly observed the lateral image of penetrated Pd in depth. In this work, we used electrochemically anodized-silicon wafer doped with Pd by the electroless process. In our analysis, we intentionally characterized both the area of PS where Electric Field is applied during silicon etching (EF area) and the Field Free region (FF area) of the sample. Microbeam analysis show that EF area of the sample is covered with thicker palladium layer, but the pores are rarely filled in this area, while in the FF area of the sample, there is a thin palladium film on the silicon surface, but the pores are partially filled. We used a computational simulation method based on columnar pore structure and linear variation of Pd depth profile in pores and determined the lateral variation of Pd penetration in pores in both parts of the sample. These simulations showed that there are 180±80nm thick Pd layer with 300±200nm penetration in pores in EF region and 80±40nm thin Pd layer with 800±200nm penetrate in pores in FF region. [Copyright &y& Elsevier]

Abstract: A novel vacuum chamber for ion beam analysis of large-size industrial samples – whose analysis are not feasible in conventional ion beam analysis reaction chambers – has been designed, fabricated and successfully tested. Using the newly developed chamber, both PIXE and RBS analyses could be carried out at the same time and on the same point of the samples. Ion beam analysis using this novel chamber lacks the disadvantages of external beam analysis and benefits the advantages of in-vacuum analysis. This has been achieved by designing a tiny open port in the wall of the reaction chamber to be sealed with a small flat area of sample body where its analysis is of interest. As a case study, two samples of gas turbine blades, a corroded one at highly corrosive environment and a refurbished one after application of certain coatings are analysed using the novel chamber. Experimental results confirm the performance and capability of the reaction chamber. [Copyright &y& Elsevier]

Refurbishment of hot components of gas turbines damaged in the harsh working environments is necessary to increase their lifetime. Scanning proton microscopy was employed to evaluate the quality of refurbishment process of gas turbine blades. Distribution patterns of different elements were observed in the polished cross-sections of turbine blade samples by proton microbeam. In the cross-sections of refurbished and used samples, distinct regions were identified corresponding to the base superalloy, original protection layer and applied coating for refurbishment. The elemental composition of each of these regions was measured by Micro-PIXE analysis. Inhomogeneous and high content of Si as well as undesired light elements were observed in the cross-sections of refurbished samples, indicating imperfections in the refurbishment process. [ABSTRACT FROM AUTHOR]

High Vacuum thermal evaporation was used to grow germanium islands on the silicon substrate covered by silicon oxide. The Ge nano-islands were formed by thermal annealing at different temperatures from 500 °C to 700 °C. Formation of islands was studied by various analytical techniques. The thickness of Ge layer was determined by rutherford backscattering spectroscopy (RBS). Also, combined with channeling technique, the composition and probable contaminants during synthesis processes were investigated. To explore the islands size and shape, both atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) were used. Then the topographical images of surfaces were studied by AFM. The outcome of experimental evaluations of growth mechanism has indicated that with increasing the annealing temperature up to 700 °C, Ge islands were appeared from a uniform layer. Moreover, the statistical assessments of surfaces have shown that the nano-island's sizes can be varied from several hundred nanometers to 30 nm by growing the annealing temperature. The reduction of the size along with an increase of the number of nano-islands after each thermal treatment is a major factor to prohibit us from seeing their clear images in AFM. The possibility of running statistical estimation on islands, instead, is the powerful tool of extracting and probing the distribution and the shape of Ge island's peak in AFM images. [ABSTRACT FROM AUTHOR]