Download or read book Materials Analysis Using Positron Beam Lifetime Spectroscopy written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We are using a defect analysis capabilities based on two positron beam lifetime spectrometers: the first is based on a 3 MeV electrostatic accelerator and the second on our high current linac beam. The high energy beam lifetime spectrometer is routinely used to perform positron lifetime analysis with a 3 MeV positron beam on thick sample specimens. It is being used for bulk sample analysis and analysis of samples encapsulated in controlled environments for in situ measurements. A second, low energy, microscopically focused, pulsed positron beam for defect analysis by positron lifetime spectroscopy is under development at the LLNL high current positron source. This beam will enable defect-specific, 3-dimensional maps of defect concentration with sub-micron location resolution. When coupled with first principles calculations of defect specific positron lifetimes it will enable new levels of defect concentration mapping and defect identification.

Download or read book Bulk Materials Analysis Using High Energy Positron Beams written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This article reviews some recent materials analysis results using high-energy positron beams at Lawrence Livermore National Laboratory. We are combining positron lifetime and orbital electron momentum spectroscopic methods to provide electron number densities and electron momentum distributions around positron annihilation sites. Topics covered include: correlation of positron annihilation characteristics with structural and mechanical properties of bulk metallic glasses, compositional studies of embrittling features in nuclear reactor pressure vessel steel, pore characterization in Zeolites, and positron annihilation characteristics in alkali halides.

Download or read book Positron Profilometry written by Jerzy Dryzek and published by Springer Nature. This book was released on 2023-09-08 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of positron profilometry, specifically focusing on the analysis of defect depth distribution in materials. Positron profilometry plays a crucial role in understanding and characterizing defects in a wide range of materials, including metals, semiconductors, polymers, and ceramics. By analyzing the depth distribution of defects, researchers can gain insights into various material properties, such as crystal structure, defect density, and diffusion behavior. The author's extensive research spanning a period of two decades has primarily centered on subsurface zones. These regions, located beneath the surface and subjected to various surface processes, play a crucial role in generating defect distributions. Three experimental techniques and their data analysis are described in detail: a variable-energy positron beam (VEP) called sometimes a slow positron beam, a technique called implantation profile depth scanning (DSIP), and a sequential etching (SET) technique. The usability of these techniques is illustrated by many examples of measurements by the author and others.

Download or read book Bulk Defect Analysis with a High energy Positron Beam written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A program using a positron beam to probe defects in bulk materials has been developed at Lawrence Livermore National Laboratory. Positron annihilation lifetime spectroscopy (PALS) provides non-destructive analysis of average defect size and concentration. A 3 MeV positron beam is supplied by Sodium-22 at the terminal of a Pelletron accelerator. The high-energy beam allows large (greater than or equal to 1 cm2) engineering samples to be measured in air or even sealed in an independent environment. A description of the beam-PALS system will be presented along with a summary of recent measuremen.

Download or read book Positron Spectroscopy of Solids written by Alfredo Dupasquier and published by IOS Press. This book was released on 1995 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lifetime of a positron inside a solid is normally less than a fraction of nanosecond. This is a very short time on a human scale, but is long enough to enable the positron to visit an extended region of the material, and to sense the atomic and electronic structure of the environment. Thus, we can inject a positron in a sample to draw from it some signal giving us information on the microscopic properties of the material. This idea has been successfully developed in a number of positron-based techniques of physical analysis, with resolution in energy, momentum, or position. The complex of these techniques is what we call now positron spectroscopy of solids. The field of application of the positron spectroscopy extends from advanced problems of solid-state physics to industrial applications in the area of characterization of high-tech materials. This volume focuses the attention on the physics that can be learned from positron-based methods, but also frames those methods in a wider context including other experimental approaches. It can be considered as a textbook on positron spectroscopy of solids, the sort of book that the newcomer takes for his approach to this field, but also as a useful research tool for the expert.

Download or read book Positron Annihilation in Semiconductors written by Reinhard Krause-Rehberg and published by Springer. This book was released on 1999-01-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive book reports on recent investigations of lattice imperfections in semiconductors by means of positron annihilation. It reviews positron techniques, and describes the application of these techniques to various kinds of defects, such as vacancies, impurity vacancy complexes and dislocations.

Download or read book Positron Annihilation Lifetime Studies of Inorganic Materials Using a New Positron Beamline written by Jason Roberts and published by . This book was released on 2012 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, effects caused by the nanoscale structure of a material have become increasingly important for technological progress. With improvements in fabrication techniques, nanoscale structures can now be produced with growing control. As a result, techniques to characterise these properties have been developed and are also becoming increasingly important. One such collection of non-destructive techniques, which can provide unique information about a target sample, is Positron Annihilation Spectroscopy (PAS). The initial aim of the research presented here was the development and characterisation of a positron beamline for materials studies. This beamline, now operational, has been developed to measure the positron lifetime in a target material. This technique, referred to as Positron Annihilation Lifetime Spectroscopy (PALS), allows the size of open volume type defects (or voids) up to 10 nm to be determined. In addition, as the technique is implemented using a variable energy positron beam, thin film samples can be characterised and measurements can be performed in a depth sensitive manner. The beamline uses a Surko trap to isolate and cool positrons from a moderated radioactive source. Positrons are released from the trap using a timed potential ramp, though hardware restrictions limit the effectiveness of this technique. This arrangement results in a pulsed positron beam of up to two thousand pulses per second with a temporal Full Width at Half Maximum (FWHM) of 800 ps. Typical spectra, which contain 1 000 000 counts, can be recorded in two hours; although to resolve shorter lifetime components (

Download or read book Positron Annihilation Spectroscopy with Magnetically Analyzed Beams written by and published by . This book was released on 1982 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Positron Annihilation in Semiconductors written by Reinhard Krause-Rehberg and published by Springer Science & Business Media. This book was released on 1999 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive book reports on recent investigations of lattice imperfections in semiconductors by means of positron annihilation. It reviews positron techniques, and describes the application of these techniques to various kinds of defects, such as vacancies, impurity vacancy complexes and dislocations.

Download or read book Progress in Materials Analysis written by M. Grasserbauer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vol. 2 of "Progress in Materials Analysis" contains the lectures of the 12th Colloquium on Materials Analysis, Vienna, May 13-15, 1985. Due to the top level international participation from industry and research insti tutions the proceedings offer a survey of the present state and current trends in materials analysis of high actuality. The major topics covered are surface, micro and trace analysis of materials with a special emphasis on metals but also including other materials like ceramics, semiconductors, polymers. According to the strategy of the meeting attention is focussed on an interdisciplinary approach to materials science - combining analytical chemistry, solid state physics and technol ogy. Therefore progress reports on modern analytical technique like SIMS, SNMS, AES, XPS, Positron Annihilation Spectroscopy, EPMA, STEM, LAMMS, etc. are contained as well as presentations on the development of materials. The majority of the contributions centers on the treatment of important problems in materials science and technology by a (mostly sophisticated) combination of physical and chemical analytical techniques. Vienna, July 1985 M. Grasserbauer Contents Page Hercules, D. M. Surface Characterization of Thin Organic Films on Metals ............................................. .

Download or read book Construction and Testing of a Positron Annihilation Lifetime Spectrometer written by Brian M. Wieland and published by . This book was released on 2012 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation Lifetime Spectroscopy (PALS) is a nuclear technique that was developed in the 1970s as a method to assess defects in materials. This technique has tremendous potential as a powerful tool for non-destructive quantification of the types and densities of defects within solids. Following the injection of positrons into a solid material, the positrons pair-annihilate at a rate dependent upon the density of electrons near the injection site. If there are lattice vacancies or dislocation defects near the injection site, the positrons are attracted to these areas, which have lower electron densities and thus give rise to longer positron lifetimes. Typical positron lifetimes in defect-free conductor-type metals are -'-'1OO ps, while lifetimes within defect regions are 2OO ps. In order to discern between these minute lifetime differences, a spectrometer with very good timing resolution has been constructed and optimized. The capabilities of the spectrometer have been tested using a 22Na positron emitter by performing source-based measurements of positron lifetimes in high-purity samples of aluminum, nickel, copper, and lead. Test results are in excellent agreement with currently accepted literature values, thus validating the apparatus and data analysis technique. This study is an important first step towards the development of a modern positron annihilation lifetime spectrometer for use in accelerator-based, gamma-induced positron annihilation spectroscopy (AG-PAS).

Download or read book Positron Beams and Their Applications written by Paul G. Coleman and published by World Scientific. This book was released on 2000 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a coherent and comprehensive overview of the generation and application of mono-energetic positron beams. It has been written by acknowledged experts, at a level accessible to graduate students working, or planning to work, with positron beams, and to scientists in other areas who want to know something about the field.The book begins with a brief historical introduction and an overview of how positron beams are generated and transported. A description of the fate of slow positrons in gaseous and condensed matter, with reference to many of the fundamental measurements made possible by the advent of positron beams, is followed by a discussion on applications in the study of solid surfaces, defect profiling in subsurface regions, interfaces and thin films, and the probing of bulk properties in novel ways. The book ends with a look at the future, considering the prospects for intense positron beams and their potential for further research.

Download or read book Principles and Applications of Positron Positronium Chemistry written by Y. C. Jean and published by World Scientific. This book was released on 2003 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive description of the principles and applications of positron and positronium chemistry. Pedagogical and tutorial in nature, it will be ideal for graduate students and researchers in the area of positron annihilation spectroscopy. The contributing authors are authoritative scientists prominent in the frontiers of research, actively pursuing positron annihilation research on chemical and applied systems. Contents: Introduction to Positron and Positronium Chemistry (Y C Jean et al.); Compounds of Positrons and Positronium (D M Schrader); Experimental Techniques in Positron Spectroscopy (P G Coleman); Organic and Inorganic Chemistry of the Positron and Positronium (G Duplotre & I Billard); Physical and Radiation Chemistry of the Positron and Positronium (S V Stepanov & V M Byakov); Positrons and Positronium in the Gas Phase (D M Schrader); Positron Porosimetry (M H Weber & K G Lynn); Positron Annihilation Studies on Superconducting Materials (C S Sundar); Positronium in Si and SiO 2 Thin Films (R Suzuki); Applications to Polymers (P E Mallon); Applications of Slow Positrons to Polymeric Surfaces and Coatings (Y C Jean et al.); Positron Annihilation Induced Auger Spectroscopy (S Amdani et al.); Characterization of Nanoparticle and Nanopore Materials (J Xu); AMOC in Positron and Positronium Chemistry (H Stoll et al.). Readership: Materials science researchers; physical chemists; polymer scientists and engineers; chemical and mechanical engineers; solid state physicists; graduate students in chemistry, physics, engineering and polymer science; coating industry researchers."

Download or read book Positron and Positronium Chemistry written by S.J. Wang and published by Trans Tech Publications Ltd. This book was released on 2008-11-06 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this special volume was to provide an international forum within which to present the recent progress made in positron and positronium chemistry, and to exchange new ideas in fields of research which use positrons and positronium. Volume is indexed by Thomson Reuters CPCI-S (WoS).

Download or read book The Analysis of Nuclear Materials and Their Environments written by Claude André Degueldre and published by Springer. This book was released on 2017-10-11 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of passive and interactive analytical techniques for nuclear materials. The book aims to update readers on new techniques available and provide an introduction for those who are new to the topic or are looking to move into actinides and nuclear materials science. The characterization of actinide species and radioactive materials is vital for understanding how these elements and radioactive isotopes are formed and behave and how these materials can be improved. The analysis of the actinides or radioactive materials goes beyond spent fuel science to the applicable complete fuel cycle and including analysis of reactor materials.

Download or read book Analysis of Positron Lifetime Spectra in Polymers written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new procedure for analyzing multicomponent positron lifetime spectra in polymers was developed. It requires initial estimates of the lifetimes and the intensities of various components, which are readily obtainable by a standard spectrum stripping process. These initial estimates, after convolution with the timing system resolution function, are then used as the inputs for a nonlinear least squares analysis to compute the estimates that conform to a global error minimization criterion. The convolution integral uses the full experimental resolution function, in contrast to the previous studies where analytical approximations of it were utilized. These concepts were incorporated into a generalized Computer Program for Analyzing Positron Lifetime Spectra (PAPLS) in polymers. Its validity was tested using several artificially generated data sets. These data sets were also analyzed using the widely used POSITRONFIT program. In almost all cases, the PAPLS program gives closer fit to the input values. The new procedure was applied to the analysis of several lifetime spectra measured in metal ion containing Epon-828 samples. The results are described. Singh, Jag J. and Mall, Gerald H. and Sprinkle, Danny R. Goddard Space Flight Center; Langley Research Center...

Download or read book Electron and Positron Spectroscopies in Materials Science and Engineering written by Otto Buck and published by Academic Press. This book was released on 2014-06-28 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electron and Positron Spectroscopies in Materials Science and Engineering presents the advances and limitations of instrumentations for surface and interface probing useful to metallurgical applications. It discusses the Auger electron spectroscopy and electron spectroscopy for chemical analysis. It addresses the means to determine the chemistry of the surface. Some of the topics covered in the book are the exo-electron emission; positron annihilation; extended x-ray absorption fine structure; high resolution electron microscopy; uniaxial monotonic deformation-induced dislocation substructure; and analytical electron microscopy. The mechanistic basis for exo-electron spectroscopy is covered. The correlation of fatigue and photoyield are discussed. The text describes the tribostimulated emission. A study of the quantitative measurement of fatigue damage is presented. A chapter is devoted to the fracture of oxide films on aluminium. Another section focuses on the positron annihilation experimental details and the creep-induced dislocation substructure. The book can provide useful information to scientists, engineers, students, and researchers.