X-ray emission particle induced

PIXE is a method using X-ray emission for elemental analysis. A high energetic proton beam excites emission of characteristic X-rays from the sample atoms due to inner-shell ionisation. PIXE is not a true nuclear technique, since the ionisation of the atoms by the ion beam and the subsequent emission of characteristic X-rays are purely atomic electromagnetic (rather than nuclear) processes. Methods and data for using K and L lines of X-rays, produced by ion beams (mostly proton beams) are well established and thick or thin samples can be analysed with an absolute precision of 10 % or better. 

The main advantages of PIXE are its good sensitivity, multi-element capabihty 

in particular protons from a particle accelerator, in the energy range 1 —4 MeV, are used with beam spots 1 pm—10 mm in diameter. a-Particles from some radioactive sources ( Am) can also be used for excitation. The energy of emitted photons is measured by a wavelength dispersive Bragg spectrometer or by an energy-dispersive spectrometer with semiconductor Si(Li) or Ge(Li) detectors. 

PIXE is able to investigate solid samples with sizes of the order of a cm and thicknesses on the scale of micrometers. However, PIXE can also be used for unusual samples like liquids and gases. Due to low absorption of X-rays in the sample it is better to investigate thin samples, the composition of which can be determined with better accuracy. 

A typical PIXE spectrum of a sample from environmental research is shown in Fig. 13.4. 

Particle-induced X-ray emission (PIXE) is an analytical technique based upon observing fluorescent X-rays. As such, it really is not a nuclear technique since it involves an atomic process, X-ray emission. But the atomic electron shell vacancies that are filled when the X-ray is emitted are created using particle-accelerator beams and one uses typical semiconductor radiation detectors, Si (Li) detectors, to detect the X-rays. 

One of the most successful applications of PIXE has been in the analysis of air pollution particulate matter. Atmospheric particulate matter is typically collected by impaction on a filter paper, which provides an ideal thin sample for PIXE analysis. Another aspect of PIXE that is very important for the analysis of aerosol samples is the ability to analyze a large number of samples in a short time. PIXE analyses typically take less than a minute, and the entire irradiation, counting, sample changing, and analysis procedure can be automated. 

An important variant on PIXE is micro-PIXE. By using a proton beam whose spatial dimension is 0.5 pm (rather than the usual 10 mm), one can determine the trace-element content of a small portion of the sample, giving one a trace-element microscope. This application is important in probing samples of medical interest. A related technique is used in the electron microprobe where the ionization is caused by electron impact. 

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. 

EP = exposed group (n = 3). OB = olfactory bulb OP = olfactory peduncle ON = olfactory nerve G1 = glomerular layer Epl = external plexi-form layer. Mi = mitral cell layer Ipl = internal plexiform layer GrO = granule cell layer of olfactory bulb Md = medullary layer GrA = granule cell layer of accessory olfactory bulb AOB = accessory olfactory bulb AOE = anterior olfactory nucleus external part AOL = anterior olfactory nucleus, lateral part lo = lateral tract. (Reprinted from Wang et alP 2007 Humana Press Inc.) 

The high-resolution requirement can be achieved using micro-PIXE (p-PIXE) analysis. The detection sensitivity of p-PIXE can reach 1-10 pgg The spatial resolution is typically in the micrometer range, but 0.2 pm is achievable for the latest high-resolution instruments.  

As a complement to SRXRF, micro-PIXE analysis could also be performed to obtain quantitative element concentration on groups of several hundred cells on the same samples to complete SRXRF imaging of single cells. In the above SRXRF study by Ortega et al.J cellular iron and zinc concentrations (mgg dry mass) could be obtained by PIXE quantitative micro-analysis by the mean 

Neutron activation analysis (NAA) is a powerful quantitative method for accurate determination of total amount of element with the detection limit from 

The spectra from the rock and target were collected for 1 h. Results showed that, compared to previous Martian rocks, the Jake rock is low in Fe and Mg, but high in Na, Al, Si, and K, which are often found in feldspar minerals. The results point to an igneous or volcanic origin for the rock. 

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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... 

X-radiation can also be induced by high energy (several Me proton beams from ion accelerators. Such particle-induced x-ray emission (PIXE) (284) is useful for thin samples and particulates, having detection Hmits of g. Intense synchrotron x-ray sources have found appHcations in... 

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. 

Particle Induced X-Ray Emission Hydrogen/Helium Induced X-ray Emission... 

Vol. 133. Particle-Induced X-Ray Emission Spectrometry. By Sven A. E. Johansson, John L. Campbell, and Klas G. Malmqvist... 

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. 

Particle-induced X-ray emission (PIXE) in which electrons are ionised, and elemental specific X-rays are generated by the incident ion beam. 

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... 

Johansson, S.A., Campbell, J.L. Malmqvist, K.G. (1995) Particle-Induced X-Ray Emission Spectrometry (PIXE), John Wiley Sons, New York, Chichester. 

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

There are now several different types of machines that are all capable of microanalysis. All have advantages and disadvantages, but the choice of which to use is often governed by expense and availability to a particular institution. Electron probe microanalysis is by far the most popular, but here particle-induced X-ray emission (PIXE), the laser microprobe mass analyzer (LAMMA), electron energy loss spectroscopy (EELS), and secondary ion mass spectrometry (SIMS) are also considered. 

Hult M, BengtssonB, LarssonNP-O, Yang C. Particle induced x-ray emission microanalysis of root samples from beech (Fagus sylvatica). Scanning Microsc 1992 6 581-590. 

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