Particle-Induced -Emission Analysis

In the analysis of light elements by PIGE, the reactions by Coulomb excitation (p, p y) are common. The resonance nuclear reactions (p, y), (p, ay) are used occasionally for the depth-profile. 

Measurements of y-ray emission induced by protons on fluorine and lithium have been carried out by Caciolli et al. (2006) who measured the y-ray yields of the reactions F(p, p y) F Ey = 0.110,0.197,1.24,1.35,1.36 MeV), F(p, ay) 0 ( y = 6.13,6.92,7.12 MeV), Li(p, ny) Be (Ey = 429keV) and Li(p, p y) Li Ey = 478keV) for proton energies from 3.0 to 5.7 MeV using a 50 o.gcm LiF target evaporated on a self-supporting thin C-film. The y-rays were detected by a 38% relative efficiency Ge detector placed at an angle of 135° with respect to the beam direction. Absolute y-ray differential cross-sections were obtained for all the listed reactions with an overall uncertainty of 15%. 

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By inserting a semiconductor x-ray detector into the analysis chamber, one can measure particle induced x-rays. The cross section for particle induced x-ray emission (PIXE) is much greater than that for Rutherford backscattering and PIXE is a fast and convenient method for measuring the identity of atomic species within... 

Three techniques involving the use of X-ray emission to obtain quantitative elemental analysis of materials are described in this chapter. They are X-Ray Fluorescence, XRF, Total Reflection X-Ray Fluorescence, TXRF, and Particle-Induced X-Ray Emission, PIXE. XRF and TXRF use laboratory X-ray tubes to excite the emission. PIXE uses high-energy ions from a particle accelerator. 

Although sophisticated methods may constitute the core methods for certification it is useful to include good, well executed routine methods. In order to further minimize systematic error, a conscious purposeful attempt should be made to get methods and procedures with wide-ranging and different sample preparation steps, including no decomposition as in instrumental neutron activation analysis and particle induced X-ray emission spectrometry. 

Neutron Activation Analysis X-Ray Fluorescence Particle-Induced X-Ray Emission Particle-Induced Nuclear Reaction Analysis Rutherford Backscattering Spectrometry Spark Source Mass Spectrometry Glow Discharge Mass Spectrometry Electron Microprobe Analysis Laser Microprobe Analysis Secondary Ion Mass Analysis Micro-PIXE... 

Principles and Characteristics Particle-induced X-ray emission spectrometry (PIXE) is a high-energy ion beam analysis technique, which is often considered as a complement to XRF. PIXE analysis is typically carried out with a proton beam (proton-induced X-ray emission) and requires nuclear physics facilities such as a Van der Graaff accelerator, or otherwise a small electrostatic particle accelerator. As the highest sensitivity is obtained at rather low proton energies (2-4 MeV), recently, small and relatively inexpensive tandem accelerators have been developed for PIXE applications, which are commercially available. Compact cyclotrons are also often used. 

A publication by Johansson et al. (1970) over thirty years ago marks the introduction of this technique of particle-induced X-ray emission analysis. They used protons and... 

Ion beam spectrochemical analysis Auger emission spectroscopy Scanning electron microscopy (SEM) Electron microprobe (EMPA) Particle-induced X-ray emission spectroscopy (PIXE)... 

Perezarantegui, J., Querre, G., and Castillo, J. R. (1994). Particle-induced X-ray-emission -thick-target analysis of inorganic materials in the determination of light-elements. Journal of Analytical Atomic Spectrometry 9 311-314. 

The fine particle airstream from the cyclone was sampled by two total filters in parallel. A Millipore Fluoropore 47 mm diameter Teflon filter with a 1 pm pore size was used for the first seven samples. Subsequent samples were obtained with a 0.4 pm pore size 47 mm Nuclepore polycarbonate filter because particle absorption measurements and elemental analysis by particle induced X-ray emission (PIXE) were easier and more accurate using the Nuclepore filters. In parallel with the Nuclepore filter, a TWOMASS tape sampler collected aerosol using a Pallflex Tissuequartz tape. The aerosol deposit area was 9.62 cm on the Nuclepore and Millipore filters and 0.317 cm on the Tissuequartz tape. The flow rate was 16-20 1pm through the Nuclepore and Millipore filters and 10 1pm through the Tissuequartz tape. Each Millipore or Nuclepore filter was placed in a labeled plastic container immediately after collected, sealed with Parafilm, enclosed in a ziplock bag, and placed in a refrigerator in the trailer. The tape in the TWOMASS sampler was advanced between samples. The tape sample was removed about once every 8-10 weeks and stored similarly to the Nuclepore filters. The TWOMASS was cleaned at that time. All samples were stored in an ice chest during the return trip to Caltech. Field blanks were handled identically to the samples. Of approximately 100 filter samples collected in 1979, 61 were selected for analysis. The 61 were chosen to span the variation in bjp and to obtain representative seasonal and diurnal samples. Sample times varied from 6 to 72 hours, with an average of 20.1 hours. 

Elemental mass concentration - One-third of each Nuclepore filter was sent to Crocker Nuclear Laboratory, University of California, Davis, for elemental analysis by particle induced X-ray emission (PIXE)(14). Masses of many elements from A1 to Pb were determined with this technique, including Si, S, K, Ca,... 

The aerosol samples collected by the SFU were analyzed both gravimetrlcally for total suspended particulate mass less than 15pm, and by particle induced x-ray emission (PIXE) for elemental content. The filters were weighed before and after sampling using a Cahn 25 electrobalance sensitive to Ipg. Typical precision of TSP determined by this analytical method is 0.5pg/m for samples collected under conditions of low aerosol concentrations ( ). After weighing, the filters were analyzed for elemental content (elements heavier than Na) using the UC Davis PIXE system. This analysis technique is described in Cahill al ( ). 

Traxel, K., and U. Watjen, Particle-Induced X-Ray Emission Analysis (PIXE) of Aerosols, in Physical and Chemical Characterization of Individual Airborne Particles (K. R. Spumy, Ed.), Chap. 16, pp. 298-330, Ellis Horwood, Chichester, 1986. 

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. 

Since the mid-1960s, a variety of analytical chemistry techniques have been used to characterize obsidian sources and artifacts for provenance research (4, 32-36). The most common of these methods include optical emission spectroscopy (OES), atomic absorption spectroscopy (AAS), particle-induced X-ray emission spectroscopy (PIXE), inductively coupled plasma-mass spectrometry (ICP-MS), laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectroscopy (XRF), and neutron activation analysis (NAA). When selecting a method of analysis for obsidian, one must consider accuracy, precision, cost, promptness of results, existence of comparative data, and availability. Most of the above-mentioned techniques are capable of determining a number of elements, but some of the methods are more labor-intensive, more destructive, and less precise than others. The two methods with the longest and most successful histoty of success for obsidian provenance research are XRF and NAA. 

The use of particles heavier than electrons, and especially proton-induced x-ray emission analysis, was developed under the supervison of Professor Sven Johansson at Lund University, Sweden, during the 1970s.9 Generally referred to as PIXE (particle- or proton-induced x-ray emission) analysis, it has proven to be a sensitive trace element technique. The initial response among medical researchers was a cautious one, most likely due to the fact that the problems of specimen preparation initially were... 

Forslind, B. etal., Elemental analysis on freeze dried sections of human skin studies by electron microprobe and particle induced x-ray emission analysis, Scanning Electron Microsc., 2, 755, 1984. 

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. 

In the following, those ion beam analysis techniques that allow for fluorine detection will be presented. By far, the most important technique in this respect is nuclear reaction analysis (NRA). Although it can be rather complex to perform, it is the most often applied technique for fluorine trace element studies, due to a number of convenient and prolific resonant nuclear reactions which make it very sensitive to fluorine in most host matrices. NRA is often combined with particle-induced X-ray emission (PIXE) which allows for simultaneous determination of the sample bulk composition and concentrations of heavier trace elements. By focusing and deflecting the ion beam in a microprobe, the mentioned techniques can be used for two- or even three-dimensional multi-elemental imaging. 

The same equipment as for X-ray spectrometry is used for X-ray fluorescence analysis (XFA). In this method, emission of characteristic X rays is induced by excitation with X-ray sources (X-ray tubes or X-ray emitting radionuclides) or with charged particles (PIXE, i.e. particle-induced X-ray emission). 

Total reflection X-ray fluorescence analysis Electron microprobe analysis Particle induced X-ray emission Synchrotron radiation induced X-ray emission... 

Particle-Induced X-ray Emission, PIXE Nuclear Reaction Analysis, NRA Hydrogen Mass Spectrometry, HMS Noble Gas Mass Spectrometry, NGMS... 

Extended Analysis of Satellite Structures in Particle Induced X-ray Emission Spectra Using Molecular Orbital Calculations... 

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