Download or read book Positron Annihilation Reactions in Condensed Materials written by JOHN D. MCGERVEY and published by . This book was released on 1962 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements were made of the time distribution of positron annihilations in aluminum, tin, copper, titanium, and zinc. All of the metals measured to date have shown a long lived component. This component, which is still unexplained, contains from 5 to 10% of the total counts, with A MEAN LIFE OF ABOUT 4 X 10 TO THE -10TH POWER SEC IN ALL THE METALS MEASURED. The presence of the long lived component is deduc small number of counts. Nevertheless these counts are significantly above the background level the counting rate in the peak was about 5000 times the background. Short mean lives in these metals were determined by subtracting the counts in the extrapolated long lived component and measuring the slope of t e remaining distribution. Data are being obtained on the angular distribution of annihilation radiation from alloys. The angular correlation method gives a direct expd from an extremely small number of counts. Nevertheless these counts are significantly above the background level the counting rate in the peak was about 5000 times the background. Short mean lives in these metals were determined by subtracting the counts in the extrapolated long lived component and measuring the slope of t e remaining distribution. Data are being obtained on the angular distribution of annihilation radiation from alloys. The angular correlation method gives a direct experimental determination of the Fermi energy of the conduction electrons. The major difficulty with the method is that in many alloys of interest a large number of positrons annihilate with core electrons rather than conduction electrons, and it is necessary to subtract this component in order to obtain the curve for conduction electron annihilation. (Author).
Download or read book Positron Annihilation in Condensed Matter written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation written by A.T. Steward and published by Elsevier. This book was released on 2012-12-02 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation focuses on the process of positron annihilation in different environments. Partitioned into two parts with 42 chapters, the book contains the contributions of authors who have done research on the annihilation of positrons, which brought about valuable information on the properties of matter. The first part of the book deals with lengthy review articles, including a survey of the physics of positron annihilation; positron annihilation in metals and the theory involved in the process; and positron annihilation in alkali halides and ionic crystals. Positronium formation and interaction in gases, molecular substances, and ionic crystals are also given attention. Gaseous positronics and positron annihilation in condensed gases and liquids are also discussed. The second part of the book focuses on developments on positron annihilation and the direction of research on this field. The studies concentrate on positron annihilation in various crystals, metals, mercury, liquefied gases, helium, and metal oxides. Numerical representations and analyses are presented to support the processes involved. The book can best serve the interest of those who want to explore further the annihilation of positrons.
Download or read book Positron Annihilation in Chemistry written by Ole E. Mogensen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The only critical discussion available on the chemistry of the two "strange" light particles, the positron and positronium, with much space devoted to the excess electron. Positron annihilation allows the investigation of many unusual phenomena in the reaction kinetics of the positron, positronium, and excess electron, and in radiation chemistry and physics, while also providing important information on defects in solids.
Download or read book Positron Annihilation in Condensed Substances written by Mark Barrie Perkal and published by . This book was released on 1970 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Studies of Condensed Matter written by Roy Neil West and published by . This book was released on 1974 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation ICPA 11 written by Yan Ching Jean and published by Trans Tech Publications Ltd. This book was released on 1997-09-18 with total page 852 pages. Available in PDF, EPUB and Kindle. Book excerpt: For one and a half decades, the application of positron annihilation to condensed-matter physics concentrated on the study of the Fermi surfaces of metals and alloys. As other, often more powerful, techniques for performing this type of study were developed, it appeared that condensed-matter positron physics was going to be relegated to being a niche interest. However, the situation changed dramatically when it was found that measurements of positron annihilation in metals were sensitive to the structures of well-known defects. This discovery, and subsequent research made it a major tool in materials science. Volume is indexed by Thomson Reuters CPCI-S (WoS).
Download or read book Positron Spectroscopy of Solids written by Società italiana di fisica and published by IOS Press. This book was released on 1995 with total page 807 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 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 Annihilation Studies of Solids and Surfaces written by Paul Richard Guagliardo and published by . This book was released on 2011 with total page 255 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] This thesis describes the first positron annihilation studies undertaken in the Atomic, Molecular and Surface Physics group in the School of Physics at the University of Western Australia (UWA). We have studied a range of systems with differing positron annihilation characteristics with the aim of characterising their defect properties, and in the process have gained insight into the interactions of positrons and positronium with materials. The project started with establishing a positron annihilation laboratory. This entailed developing procedures to produce and safely handle sealed 22Na sources, and testing positron annihilation instrumentation and experimental methods. The project evolved through collaboration with physicists, engineers, chemists, materials scientists, metallurgists and medical scientists and through a number of interesting experimental explorations of the physical phenomena affecting positron annihilation. An overview of these investigations and a thesis synopsis is given below. Chapter 1 is an introduction to positron annihilation techniques, concentrating on the interactions of positrons (and positronium) with materials, and on the spectroscopies that exploit the annihilation processes for the purpose of studying condensed matter systems. Chapter 2 describes the testing and optimisation of the positron annihilation lifetime spectrometer and Doppler broadening spectrometer. In Chapter 3, positron annihilation has been applied to study cation vacancies in oxides that exhibit ionic bonding. Such vacancies have a relative negative charge and so attract positrons, and the relatively low electron density at these sites causes enhanced positron lifetimes. Oxides considered in this work are (a) rutile, (Ti,Nb)O2, sintered in air and Ar; (b) tin oxide, (Sn,Nb)O2 sintered in air; (c) monoclinic zirconia, (Zr,Nb)O2; (d) pollucite, Cs(1-x)Al(1-x)Si(2+x)O6 and (e) Ta- and Ti-doped Zn2TiO4. All systems except (c) showed enhanced lifetimes when doping or off-stoichiometry was increased. In Chapter 4, positron annihilation has been used to study the nanoporosity of cementitious materials. The mechanical properties of these materials are heavily influenced by porosity, with the volume and size distribution of pores controlling both the strength and durability of the material...
Download or read book AFOSR written by United States. Air Force. Office of Scientific Research and published by . This book was released on 1968 with total page 968 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation written by Wayne State University and published by . This book was released on 1967 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation ICPA 10 written by Yuan Jin He and published by Trans Tech Publications Ltd. This book was released on 1994-11-24 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Annihilation - ICPA-10 presents new results and ideas of researchers who seek more profound understanding of the nature of positron annihilation. All these scientific and technological thoughts are included in these two-volume proceedings, which contain 7 review talks, 203 contributed papers (among them, 20 are invited), and 3 summary talks. The volume is complete with keyword and author indices.
Download or read book Positron Studies in Condensed Matter Selected Papers for the INT Positron Workshop M D unchen August 1988 written by Ashraf Alam and published by CRC Press. This book was released on 1989-07 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron Studies of Condensed Matter highlights some of the outstanding recent achievements from the use of positron annihilation in solid state physics and outlines possible future trends. Current research is reviewed in authoritative articles by some of the leading practitioners in the field. Important new results in the study of electron momentum densities, Compton scattering and high-temperature superconductors are considered in detail, and the currently developing area of gas-defect interactions is also reviewed. The latest work on applications of poistron microbeams is also included. This volume contains the invited papers and selected contributed papers from the International Workshop on Positron Annihilation in Condensed Matter, held in Munich in August 1988. The emphasis of the meeting was on the most significant results of recent years in this constantly expanding field. Presenting the most important up-to-date data on the subject, Positron Studies of Condensed Matter is an important reference volume for all workers in positron physics, solid state physics, metallurgy and materials science, and will be useful to final-year undergraduates studying solid state physics.
Download or read book Positron Studies of Condensed Matter written by Roy Neil West and published by . This book was released on 1973 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation in Condensed Hydrocarbons written by Garry Alphonse De Blonde and published by . This book was released on 1972 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Positron Annihilation in Condensed Hydrocarbons written by De Blonde, Garry R. A and published by 1972.. This book was released on 1972 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
