The problems and potential of ion beam techniques in archaeology and art: nuclear reaction analysis

The main features of nuclear reaction analysis techniques are compared with other ion beam techniques in the context of their usefulness in archaeometry. A new approach to equipment layout is proposed for dedicated use in measurements on artefacts and art objects.     

Applications of ion beam analysis in archaeology and the arts

Ion beam techniques are widely used for the nondestructive analysis of objects of art and archaeology. With simple, fast, and direct procedures practically all chemical elements present in the object can be identified, and determined quantitatively with good sensitivity, accuracy and precision. The external beam technique gives the possibility of examining all articles of any size and shape without sampling. Thus, valuable information can be obtained for the composition of the objects, for the fabrication techniques, the origin of materials, etc. This information may be used for purposes of historical interest, for restoration procedures, for identification of forgeries, and many other aspects. Examples are described briefly for dating by fluorine determination, for studies on coins ceramic surfaces, old paintings, etc.     

Diffusion studies using ion beam analysis

The combination of ion implantation with nuclear methods such as Rutherford Backscattering Spectrometry (RBS), Nuclear Reaction Spectroscopy (NRS) or Elastic Recoil Detection Analysis (ERDA) has shown to be well adapted to the study of impurity migration in solids induced by either thermal annealing or irradiation. This paper gives some typical examples studied in more detail in our laboratory. Among them, the determination of thermodynamical data (diffusion coefficients, activation energies) from the analysis of the evolution of implanted species is rather classical. As an illustration the diffusion study of lanthanum implanted into apatite using RBS is presented. This work is of interest with regard to nuclear waste storage in geological sites where apatites are possible migration barriers to radioactivity and lanthanum is a representative fission product. The second study taken from the metallurgical field concerns the determination of the nitrogen diffusion coefficient into aluminium using NRS. Finally, a study concerning hydrogen diffusion in an a-SiC:H material (plasma facing materials) induced by deuterium bombardment will be presented. The hydrogen profiling is performed using ERDA.     

Review of accelerator gadgets for art and archaeology

For 30 years analytical methods based on ion beams have been progressively adapted to art and archaeological issues. By allowing the analysis of artefacts in a non-invasive and non-destructive way, the external beam represents the cornerstone of this evolution. In order to reach in air specifications usually obtained under vacuum, improvements in various directions have been necessary. A large panel of gadgets and experimental arrangements have been designed such as a multi-detector set-up operating in helium atmosphere to extend the range of measured elements, a nuclear microprobe at atmospheric pressure for the study of microscopic details or a reliable beam monitoring system. In addition, specific procedures have been developed to characterise multi-layered samples (easel paintings, alteration layers) by varying either the beam energy or the impinging angle. To improve the sensitivity to trace elements in high-Z materials like metals or for analysing targets too sensitive to stand direct exposure to charged particles, a specific X-ray fluorescence set-up (PIXE-XRF) based on the production of quasi-monochromatic X-rays has been developed. Eventually, the ion beam methods usually restricted for external beams to those based on photon detection (PIXE, PIGE) have been recently extended to methods based on charged particle detection (RBS, NRA and even ERDA), opening new perspectives for determination of light elements and depth profiling. This paper makes an historical review of the adaptation of IBA methods to the study of cultural heritage.     

Recent advances for ion beam therapy accelerators using synchrotrons

Ion beam therapy has evolved a lot during the last years. After more than a decade of successful clinical studies and first treatment in hospital environment, the carbon beam treatment, which always relies on a synchrotron as main accelerator, has clearly shown its own potential. The clinical success of carbon beam treatment is indicated by the growing number of new fully clinical based facilities. There is a lot of improvement potential for these facilities in order to increase their treatment quality, functionality and capacity as well as the cost effectiveness of the patient treatment. This article focuses on the currently ongoing investigations to fully explore this potential. It can be concluded that synchrotron based ion beam facilities are improving into many directions. This will further improve their impact on the cancer treatment and consequently their benefit to the whole society.     

Heavy ion beam driven inertial confinement fusion target studies and reactor chamber neutronic analysis

A review of heavy ion beam driven target studies and reactor chamber neutronic analysis at the Institute for Neutron Physics and Reactor Technology of the Nuclear Research Center Karlsruhe is presented. Based on a single shell, multi-layered 4 mg deuterium-tritium (DT) target design, key issues of the inertial confinement fusion target behavior are discussed. These issues are: ion beam energy deposition within the target; equations of state for the different target materials under the extreme conditions encountered; numerical simulation of target compression, ignition and burn including possible instabilities; transport processes of photons, neutrons, gammas, and alphas; and reactor chamber neutronics including target spectra, blanket and first wall analysis. For most of these issues the present physics understanding is briefly reviewed, the available calculational tools are mentioned, and key problems, which need further research and development efforts, are identified. One important feature of this paper is a consistent treatment of the 4 mg DT target behavior and of the corresponding reactor chamber neutronic analysis.     

离子束分析在艺术和考古学中的应用

本文通过与运用其它分析技术的同类工作进行比较来述评离子束分析法在艺术和考古学研究中的应用。为了说明离子束分析法的利弊,精选了一些实例来阐述该方法在艺术和考古学领域中的发展趋势和重要成就。     

离子注入、分析联用靶室

近年来,离子注入和离子束分析技术,应用相当广泛,已扩展到许多新的领域,形成了一种多学科性的边缘学科。 离子注入已作为一种成熟的技术广泛地应用在半导体工业上,在半导体制造工艺方面,它比传统的热扩散法显示出多方面的优越性。同时在材料改性方面也引起人们的极大兴趣,许多金属部件在实际使用时起作用的是金属表面的性质,而离子注入正好是能够改变金属表面性质(如硬度、磨损、腐蚀等)的有效途径。此外,离子注入技术用来改变光学表面指定区域的反射率、折射率,这在“集成光学”中是一项有效技术,也有人利用离子注入技术研制记忆元件(如磁泡)以及提高超导材料的超导性能等。     

Materials analysis using ion beam techniques

Basic concepts of ion beam analysis techniques for the study of the composition and structure of surfaces, interfaces and thin layers are reviewed. For surface characterization the use of low-energy (1–20 keV) ions is compared with the use of medium-energy (50–200 keV) and high-energy (200 keV-several MeV) ions. Thin-layer analysis with Rutherford backscattering (RBS) and nuclear reaction analysis in combination with channeling is described in detail. Requirements, including the necessary precision demands, for the instrumentation are discussed. The analysis via computer simulations of channeling data, in particular of data for the determination of lattice sites of solute atoms in single crystals, will be treated. As an illustration of the potential of ion beam techniques for structure analysis, a number of examples of lattice site locations is presented.     

北师大串列加速器在气溶胶离子束分析上的新进展

气溶胶样品中Z＞12元素含量的质子X射线荧光分析是北师大GIC4117串列加速器的主要应用领域之一.为弥补该方法不能分析H、C、N和O等轻元素之不足,我们通过在PIXE靶室40°和160°散射角安装金硅面垒探测器,用质子前角弹性散射分析和非卢瑟福背散射方法对核孔膜采集的气溶胶样品中H、C、N和O等轻元素的含量进行了测量.     

B-Ni、B-Fe系离子束混合实验研究

近年来,常用离子束混合法来研究二元金属系统的合金化问题。但是,在用离子束混合法研究类金属-金属二元系统结构变化方面,除掉Si与Pt、Pd等金属的单层膜反冲混合外,迄今还未见有研究资料发表。然而,类金属元素在金属的离子束表面改性中,以及在用其它方法形成非晶态等的研究中,是常用的元素。因此,研究类金属-金属在离子束作用下的结构变化具有现实意义。     

Instrumentation and application of the ion beam analysis line of the in situ ion beam system

An ion beam analysis system was established on a 1.7 MV tandem accelerator, enabling Rutherford backscattering(RBS), elastic recoil detection(ERD), nuclear reaction analysis(NRA) and channeling measurements. The system was tested by performing qualitative and quantitative analysis of Si, Ni/Si, Bi Fe O3:La/Si,Mo C/Mo/Si and Ti BN/Si samples. RBS of a Bi Fe O3:La film was used as system calibration. Tested by ion beam channeling, a Si(100) is of good crystallinity(χmin= 3.01%). For thin film samples, the measured thickness agrees well with simulation results by SIMNRA. In particular, composition of a Mo C/Mo/Si and Ti BN film samples were analyzed by RBS and non-Rutherford elastic backscattering.     

Infrared analysis of ion beam irradiated polymers

Irradiation with heavy ions can produce several modifications in the chain structure of polymers. These modifications can be related to scissioning and cross-linking of chemical bonds, which depend on the ion fluence and the density of energy deposited in the material. Stacked thin film Makrofol-KG^® samples were irradiated with 350 MeV Au²⁶⁺ ions and FTIR absorption spectroscopy was used to determine the bond changes in the samples. Data on the absorption bands as a function of the fluence indicated a higher probability for simple-bonds scissioning than for double-bonds scissioning and no dependence on the number of double bonds breaking with ion fluence. Since sample irradiation was done in a non-track-overlapping regime, a novel process for double bonds formation is suggested: the excitation of a site in the material by only one incident ion followed by a double bond formation during the de-excitation process.     

A new ion beam analysis data format

Computational ion beam analysis (IBA) codes such as RUMP, SIMNRA, NDF, and others implement various formats to store the spectral data and to describe the experimental conditions and simulation or fit parameters. Additionally, many laboratories have developed their own internal data formats. These various data formats are isolated applications and generally incompatible. The need for a universal IBA data format (IDF) has been recognised for many years to allow easy transfer of data and simulation parameters between codes, as well as between experimentalists and data analysts. To be effective, the IDF must be transparent (easily read by an IBA practitioner), universal (catering to varying needs), and must include the most common features desired by both experimentalists who collect and archive data and by users who analyse the data. The IDF must also be readily extensible in order to include features specific to individual codes and laboratories, as well as being able to incorporate new features and options in the future. We have developed such a data format. It is currently being implemented in the most popular general purpose IBA data analysis codes. We present here its main features.     

Comparison between PIXE and XRF for applications in art and archaeology

The properties of X-ray fluorescence and particle-induced X-ray emission have been compared with special reference to applications within art and archaeology. The two techniques have each been found to have several specific merits useful in the analysis of various objects in these fields. Together they offer the museum scientist and archaeologist excellent complementary analytical tools for nondestructive multielemental analysis.     

一个PIXE-RBS离子束分析系统的刻度

四川大学原子核科学技术研究所依托2.5 MeV范德格拉夫静电加速器搭建了质子诱发X射线荧光分析(Proton Induced X-ray Emission,PIXE)与卢瑟福背散射分析(Rutherford Backscattering Spectrometry,RBS)相结合的离子束分析系统,描述了该分析系统和刻度过程。通过10个金属单质的PIXE-RBS测量,刻度得到的仪器常数H值是一条随能量变化的曲线,然后采用最小二乘法拟合确定了X射线探测器前的Mylar膜有效厚度、选择性滤膜的有效厚度和中心小孔大小,从而得到H值。为了对刻度H值进行检验,在相同实验条件下测量了标准粘土样品元素成分,测量数据与证书数据符合得较好。刻度结果将用于以后的PIXE-RBS分析。     

Suitable test structures for submicron ion beam analysis

For the precise determination of the sizes of submicron beam spots test structures with an excellent edge definition are required. For this purpose a semiconductor heterostructure consisting of an 1.62 μm GaInP epi-layer grown on (0 0 1) GaAs has been made, which provides atomically sharp edges for beam spot size measurements. Since the sample has been thinned down by standard transmission electron microscope (TEM) preparation techniques, it can be used for both PIXE and STIM. The sample has been investigated with a TEM and the ion nanoprobe LIPSION. A one-dimensional beam profile in the low current mode was determined by a STIM measurement using 2 MeV protons and yielded a FWHM of (41±4) nm, which is the smallest value reported so far for high energy nuclear micro- and nanoprobes. Furthermore we present nickel nanowhiskers produced at the GSI Darmstadt by electrochemical preparation of etched ion track membranes that have been used to obtain two-dimensional images of the shapes of submicron beam spots. For these measurements a scan over a single nickel nanowhisker having a diameter of 220 nm and a height of about 6 μm was performed.     

Computer simulation of ion beam analysis: Possibilities and limitations

Quantitative application of ion beam analysis methods, such as Rutherford backscattering, elastic recoil detection analysis, and nuclear reaction analysis, requires the use of computer simulation codes. The different types of available codes are presented, and their advantages and weaknesses with respect to underlying physics and computing time requirements are discussed. Differences between different codes of the same type are smaller by about one order of magnitude than the uncertainty of basic input data, especially stopping power and cross section data. Even very complex sample structures with elemental concentration variations with depth or laterally varying structures can be simulated quantitatively. Laterally inhomogeneous samples generally result in an ambiguity with depth profiles. The optimization of ion beam analysis measurements is discussed, and available tools are presented.     

Spin-resolved magnetic studies of focused ion beam etched nano-sized magnetic structures

Scanning ion microscopy with polarization analysis (SIMPA) is used to study the spin-resolved surface magnetic structure of nano-sized magnetic systems. SIMPA is utilized for in situ topographic and spin-resolved magnetic domain imaging as well as for focused ion beam (FIB) etching of desired structures in magnetic or non-magnetic systems. Ultra-thin Co films are deposited on surfaces of Si(1 0 0) substrates, and ultra-thin, tri-layered, bct Fe(1 0 0)/Mn/bct Fe(1 0 0) wedged magnetic structures are deposited on fcc Pd(1 0 0) substrates. SIMPA experiments clearly show that ion-induced electrons emitted from magnetic surfaces exhibit non-zero electron spin polarization (ESP), whereas electrons emitted from non-magnetic surfaces such as Si and Pd exhibit zero ESP, which can be used to calibrate sputtering rates in situ. We report on new, spin-resolved magnetic microstructures, such as magnetic “C” states and magnetic vortices, found at surfaces of FIB patterned magnetic elements. It is found that FIB milling has a negligible effect on surface magnetic domain and domain wall structures. It is demonstrated that SIMPA can evolve into an important and efficient tool to study magnetic domain, domain wall and other structures as well as to perform magnetic depth profiling of magnetic nano-systems to be used in ultra-high density magnetic recording and in magnetic sensors.     

Characterization of natural and modified zeolites using ion beam analysis techniques

Zeolites are very important materials in catalytic and industrial processes. Natural, modified and synthetic zeolites have a wide range of uses because of their good adsorption, ion exchange capacity and catalytic properties. Mexico is an import source of natural zeolites, however their utilization in the natural form is limited due to the presence of trace metallic impurities. For example, metals such as vanadium and chromium inhibit the elimination of sulfur in hydrocarbons. Therefore, it is important to know the precise composition of the zeolite material. In this work, we report the elemental characterization of zeolites using various IBA techniques. ³He⁺ and ²H⁺ beams were used to measure the major element concentrations (Si, Al, O, C) by RBS and NRA. PIXE and SEM-EDS were used to measure the total trace element content (V, Cr, Fe, Ni, Cu, Zn, Rb, Sr, Zr, Pb, etc). Additionally, XRD was used to study the zeolite crystal structure.