Surface analysis particle induced x-ray emission

See also Activation Anaiysis Neutron Activation Charged-Particle Activation Photon Activation. Atomic Emission Spectrometry Inductively Coupled Plasma. Atomic Mass Spectrometry Inductively Coupled Plasma. Mass Spectrometry Overview. Surface Analysis Particle-Induced X-Ray Emission Auger Electron Spectroscopy Ion Scattering Nuclear Reaction Analysis and Elastic Recoil Detection. X-Ray Fluorescence and Emission Wavelength Dispersive X-Ray Fluorescence Energy Dispersive X-Ray Fluorescence. 

Until now, little attention has been given to the analysis of ancient copper alloys with LA-ICP-MS. This type of material is usually analyzed with fast or instrumental neutron activation analysis (FNAA or INAA), particle induced X-ray emission (PIXE), X-ray fluorescence (XRF), inductively coupled plasma-atomic emission spectrometry or inductively coupled plasma-atomic absorption spectrometry (ICP-AES or ICP-AAS). Some of these techniques are destructive and involve extensive sample preparation, some measure only surface compositions, and some require access to a cyclotron or a reactor. LA-ICP-MS is riot affected by any of these inconveniences. We propose here an analytical protocol for copper alloys using LA-ICP-MS and present its application to the study of Matisse bronze sculptures. 

Spectrometry Overview. Mercury. Microscopy Techniques Scanning Electron Microscopy X-Ray Microscopy. Particle Size Analysis. Polychlorinated Biphenyls. Polycyclic Aromatic Hydrocarbons Environmental Aj li-cations. Radiochemical Methods Overview. Sample Handling Sample Preservation. Sampling Theory. Surface Analysis Auger Electron Spectroscopy. Tin. X-Ray Absorption and Diffraction Overview. X-Ray Fluorescence and Emission Energy Dispersive X-Ray Ruores-cence Particle-Induced X-Ray Emission. 

See also Surface Analysis X-Ray Photoelectron Spectroscopy Particle-Induced X-Ray Emission Auger Electron Spectroscopy Appearance Potential Spectroscopy Desorption Techniques Ion Scattering Low-Energy Electron Diffraction. 

Figure 5 Components (not to scale) of a typical nuclear microprobe system (A) electrostatic particle accelerator (B) primary object aperture (C) secondary collimator (D) focusing system (E) scanning system (F) video camera and microscope (G) surface barrier detector for scattered particles (H) X-ray detector (I) specimen (J) surface barrier detector for transmitted particles (STIM) (K) front-end CAMAC with data bus (L) main computer and display with elemental map. (Reprinted with permission from Maenhaut W and Malmqvist KG (2001) Particle-induced X-ray emission analysis. In Van Grieken RE and Markowicz AA (eds.) Handbook of X-Ray Spectrometry, 2nd edn. Ch. 12, pp. 719-809. New York Dekker Marcel Dekker Inc.)...

Particle Induced X-Ray Emission (PKE) is similar to EDS analysis except that it uses high-energy particles instead of electrons to create the vacancies that lead to X-ray emission. It offers orders of magnitude better detection limits for trace elements than does EDS. Transmission Electron Microscopy (TEM) and Scanning Transmission Electron Microscopy (STEM) require extensive sample preparation. When coupled with another technique (EDS for example), they can be useful in determining the nature of surface films or in illuminating the microstructural causes of corrosion. Environmental Scanning Electron Microscopes (ESEM) that are equipped with EDS spectrometers allow SEM-EDS type data to be obtained from samples in the hydrated state. 

RBS can provide absolute quantitative analysis of elemental composition with an accuracy of about 5%. It can provide depth-profile information from surface layers and thin films to a thickness of about 1 pm. In some cases, however, the high-energy beam can damage the surface. This is particularly a problem with insulating materials, such as polymers, alkali halides, and oxides. The Mars Pathfinder mission in 1997 contained an alpha proton X-ray spectrometer (APXS). In its RBS mode, the spectrometer bombarded samples with alpha particles and determined elemental composition via energy analysis of the backscattered particles. In addition to RBS, the APXS instrument was designed to carry out proton emission and particle-induced X-ray emission (PIXE) experiments. Soil and rock compositions were measured and compared to those from the earlier Viking mission. 

Particle-induced X-ray emission (PIXE) is another widely applied technique in which the surface of the specimen is scanned and thus provides information on the surface distribution of elemental species. PIXE could be applied for tissue and single-cell analysis by focusing ion beams down to a few pm cross-section. 

Megaelectron volt (MeV) ion beam techniques offer a number of non-destructive analysis methods that allow to measure depth profiles of elemental concentrations in material surfaces. Elements are identified by elastic scattering, by specific nuclear reaction products or by emission of characteristic X-rays. With nuclear microprobes raster images of the material composition at the surface can be obtained. Particle-induced gamma-ray emission (PIGE) is especially suited for fluorine detection down to the ppm concentration level. 

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