PIGE analysis and profiling of aluminium

In this work we present an alternative method for PIGE analysis of aluminium in thick samples. This method is based on the ERYA - emitted radiation yield analysis - code, which integrates the nuclear reaction excitation function along the depth of the sample. For this purpose, the excitations functions of the ²⁷Al(p,p′γ_1,2)²⁷Al reaction (with gamma-ray energies of 844 and 1014 keV) were employed. Calculated gamma-ray yields were compared, at several proton energy values, with experimental yields for thick samples made of inorganic compounds containing aluminium. The agreement is better than 5%.The 1684 keV resonance of the same reaction, with a natural width of 100 eV, was used to profile samples of Ti implanted with several doses of Al. We show that this resonance, stronger than the 992 keV resonance of the ²⁷Al(p,γ)²⁸Si usually employed for aluminium profiling, leads to similar depth resolution in shorter collection time.     

Golden glazes analysis by PIGE and PIXE techniques

We present the analysis performed on the chemical composition of two golden glazes available in the market using the PIGE and PIXE techniques at the ITN ion beam laboratory. The analysis of the light elements was performed using the Emitted Radiation Yield Analysis (ERYA) code, a standard-free method for PIGE analysis on thick samples. The results were compared to those obtained on an old glaze. Consistently high concentrations of lead and sodium were found in all analyzed golden glazes. The analysis of the samples pointed to Mo and Co as the specific elements responsible of the gold colour at the desired temperature, and allowed Portuguese ceramists to produce a golden glaze at 997 °C. Optical reflection spectra of the glazes are given, showing that the produced glaze has a spectrum similar to the old glaze. Also, in order to help the ceramists, the unknown compositions of four different types of frits (one of the components of glazes) were analysed.     

Prompt gamma emission excitation functions for PIGE analysis

A proton energy scan from 2.2 to 3.8 MeV (Δ E = 20 keV) was performed to measure differential cross sections of prompt gamma reactions on Li, B, F, Mg, Al, Si and P at θ_lab = 90°. The purpose of the present work is to provide the basic data necessary to set up the PIGE (proton induced gamma ray emission) technique for the analysis of thin and intermediate samples.     

PIXE and PIGE techniques for the analysis of Antarctic ice dust and continental sediments

An analytical procedure has been implemented in this work for an accurate geochemical characterization and quantitative analysis of the fine dust (particles diameter < 5 μm) trapped in Antarctic ice cores and the fine fraction of potential source areas (PSA) sediments by size selection, filtering and PIXE-PIGE combined measurements. The underestimation of concentrations of the lighter elements, like Na, Mg, Al and Si, due to X-ray self-absorption inside each individual aerosol particle, was also evaluated and the analytical overall accuracy tested by means of measurements performed on size selected certified mineral standards.     

The sensitivity of the PIGE analytical technique

The aim of this work is to provide a basis for the estimation of fluorine and lithium contributions to the background of gamma-ray spectra and of their influence on PIGE (Proton-Induced Gamma-Ray Emission) detection limits of lithium, boron, fluorine and sodium. Results for yields and background contributions of lithium and fluorine were obtained from measurements using samples of known composition. Detection limits were determined by extrapolation of those measurements and by calculations based on the inferred background values. Yields were converted in concentrations using the ERYA (Emitted Radiation Yield Analysis) code. This code divides the sample in sublayers parallel to its surface for the integration of the partial gamma-ray yields along the depth of the target.     

Combined PIXE/PIGE and IBIL with external beam applied to the analysis of Merovingian glass beads

New improvements on our archaeometry line at the cyclotron of the Institute of Nuclear and Atomic Physics and of Spectrometry of the University of Liège have allowed the use of PIXE/PIGE and IBIL in-air for the analysis of cultural heritage objects. The extraction is performed through a 100 nm thick Si₃N₄ window. The detection set-up consists now of two X-ray and one γ-ray detectors, together with a fiber optic UV–visible spectrometer. This set-up has already been tested for the analysis of modern corundum [1] and is now adapted to the analysis of archaeological artefacts. In this work, we have used it to analyse 216 out of the 5000 Merovingian glass beads that come from the necropolis of Bossut-Gottechain (Belgium), one of the most important ever found in Belgium.The IBA analyses confirmed the typological division of different beads groups through chemical composition that gives us new insights on fabrication techniques of glass matrices and colorants.     

Can aluminium or magnesium be a surrogate for beryllium: A critical investigation of their chemistry

The use of beryllium is still an existing question according to the studies concerning the plasma–wall interactions which are expected to occur in ITER. Prediction of erosion and co-deposition processes for ITER is necessary for the design and the material choice of the first wall. In the current configuration, it is expected that co-deposited layers containing Be, tungsten and possibly carbon will be formed. However, the toxicity of Be limits its use in many experimental facilities around the world. Using aluminium or magnesium as Be replacements in laboratory experiments would solve this problem of toxicity and handling of Be mixed materials. A critical question which automatically arises is the relevance to use Al or Mg regarding the physical and chemical properties of both elements in comparison to the co-deposited layers expected in ITER. This work provides a review of the chemical and physical properties of Al and Mg, in the respect of comparing these properties to those of Be. Thanks to the similarity of its electronegativity to Be, Al can successfully resemble Be in terms of formation of compounds, especially the oxides and possibly the hydrides. However, due to the difference in the nature of the bonding, Mg cannot be a replacement for a possible hydride deposit formation.     

Aging of beryllium

A survey of studies devoted to the possibility of increasing the plasticity of technical-purity beryllium within the temperature region 400–600°C is given. It is shown that the heat treatment of beryllium at 600–800°C leads to the deposition of the superfluous phases from the supersaturated solution. This is accompanied by a substantial change in the properties of the metal, in particular, the plastic and strength characteristics, hardness, creep, and electric resistance. The results of metallographic, electron microscopic, electron diffraction, x-ray diffraction, and other investigations of the microstructure of beryllium in various states are cited. The mechanism of the aging of beryllium is described on the basis of the available data, and practical conclusions are drawn on the possibilities of increasing the plasticity of beryllium at high temperatures.Translated from Atomnaya Énergiya, Vol. 19, No. 2, pp. 144–153, August, 1965     

The credit analysis of recycling beryllium and uranium in BeO-UO2 nuclear fuel

This study quantifies the credits of beryllium and uranium which are used as the raw materials for BeO-UO₂ nuclear fuel by analyzing the influence of their credits on the nuclear fuel cycle cost was analyzed, where the credit was defined as the value of raw materials recovered from spent fuel and the raw materials that were re-cycled. The credits of beryllium and uranium at 60 MWD/kg burn-up were –0.22 Mills/kWh and –0.14 Mills/kWh, respectively. These findings were based on the assumption that the optimal mixing proportion of beryllium in the BeO-UO₂ nuclear fuel is 4.8 wt%. In sum, the present study verified that the credits of beryllium and uranium in relation to BeO-UO₂ nuclear fuel are significant cost drivers in the cost of the nuclear fuel cycle and in estimating the nuclear fuel cycle of the reprocessing option for spent nuclear fuels.     

Characterisation of archaeological bronzes using PIXE,PIGE, RBS and AES spectrometries

A reliable knowledge of the composition of archaeological bronzes for major and trace elements is of primary interest for the archaeologist. The composition of the metal artefacts gives information on the ancient technological knowledge and may help to distinguish between prehistoric cultural traditions. Pieces of bronzes from two pre-roman sites in Spain with different cultural traits have been analysed by ion beam analytical techniques (PIXE, PIGE and RBS) and Auger electron spectroscopy (AES). Joint use of these techniques has been found to be useful as they give complementary information on elemental composition and chemical state. The possible disturbance of the patina as a mask for the determination of the original underlying bronze composition has also been studied.     

祖母绿宝石微量元素指纹的PIXE和PIGE研究

一、 引言 祖母绿宝石是普通矿物绿柱石或绿玉的一种。它的化学分子结构可以表示为:Be_3Al_2(SiO_3)_6=(BeO)_3+(Al_2O_3)+(SiO_2)_6。从分子结构计算三个主体组份的含量BeO约占14％,Al_2O_3约占19％,SiO_2约占67％。在祖母绿宝石结晶生长的过程中,这些主体元素组份可以部份地被一些微量元素所替代。替代元素的含量和元素间浓度的分布状况既给出祖母绿宝石的特征,又是形成此矿物所处地质化学和地质物理环境的指证。祖母绿宝石突出的特征是替代元素Cr使它呈现美丽的绿色。当受到质子束轰击时,样品的靶点上被激发出浓艳的红色荧光。祖母绿宝石微量元素组份的测定可提供此矿物来源地的地质环境的有价值资料。这些资料有可能指明宝石的产地,从而对于确定宝石本征价值以及人造宝石是否     

Mechanical properties and microstructure of helium-implanted beryllium

0.2 mm thick specimens of beryllium have been homogeneously implanted with helium. Implantation temperatures ranged from 100 to 600 °C, and final helium concentrations from 30 to 800 appm. Tensile tests at temperatures between 20 and 600 °C were carried out with testing temperature both equal to and lower than the implantation temperatures. For practicality all conditions of helium-implanted specimens, ductility decreased and yield and ultimate tensile strength increased as compared to the unimplanted specimens. The amount of embrittlement and strengthening, however, depended sensitively on implantation dose, implantation temperature, and tensile test temperature. The formation of helium bubbles, dislocation loops, and dislocation networks and the fracture modes were observed by transmission and scanning electron microscopy, respectively. Two ranges of embrittlement can be distinguished. They are attributed to different mechanisms: matrix strengthening is the dominant mechanism at low temperatures, and loss of grain boundary cohesion at high temperatures. It is concluded that in both temperature regimes the embrittlement is dominated by helium and not by the displacement defects introduced by its implantation.