Download or read book Defect studies in metals using positron annihilation written by Thomas Maxwell Hall and published by . This book was released on 1974 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defect Studies in Metals Alloys and Oxides by Positron Annihilation Spectroscopy and Related Techniques written by Sahil Agarwal and published by . This book was released on 2021 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positrons administer a unique non-destructive approach to probe materials with atomic-scale sensitivity and provide reliable information about the nature and size of defects. This study reflects on the powerful capabilities of positron annihilation spectroscopy (PAS) to characterize point defects at atomic-scale, which can be crucial in the development of relevant material for a wide range of applications like nuclear reactors, medical sciences, optoelectronic devices, nanotechnology, polymers etc. The work presented in this dissertation aims to gain a fundamental understanding of the defect structures in three unique material systems: Fe metal, Fe-Cr alloy, and Ce:YAG oxide by applying the methodology and concepts of PAS. A wide range of other complementary characterization techniques has also been employed to enhance the understanding. The depth-resolved PAS was used to identify vacancy clusters in ion irradiated Fe and measure their density as a function of depth. PAS measurements uncovered the structure of vacancy clusters and the change in their size and density with irradiation dose. Combining with TEM measurements led to discovering a novel mechanism for the interaction of cascade damage with voids in ion-irradiated materials.The effect of Cr alloying on the formation and evolution of atomic size clusters induced by ion irradiation in Fe-Cr alloys was also investigated using depth-resolved PAS measurements. Combining with atomic probe tomography (APT), a possible explanation for the long-standing question about the well-known resistance to radiation in Fe-Cr alloys was addressed. It was attributed to the stabilization of vacancy clusters around Cr atoms that act as indirect sinks for radiation-induced defects.The final part of this work focuses on studying the role of defects on the luminescence properties of an important photonic material, Ce:YAG. The work reports an interesting mechanism that modifies and completely reverses the photoluminescence (PL) temperature-dependent kinetics. Further, it is shown that PL temperature-dependent kinetics can be controlled by modifying microstructure and engineering defects.

Download or read book POSITRON ANNIHILATION AND ITS APPLICATION TO DEFECT STUDIES IN METALS written by and published by . This book was released on 1972 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Positron Annihilation and Its Application to Defect Studies in Metals written by and published by . This book was released on 1971 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defects in Metals Positron Annihilation Spectroscopy written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The application of positron annihilation spectroscopy (PAS) to the study of defects in metals has led to increased knowledge on lattice-defect properties during the past decade in two areas: the determination of atomic defect properties, particularly those of monovacancies, and the monitoring and characterization of vacancy-like microstructure development during post-irradiation and post-quench annealing. The study of defects in metals by PAS is reviewed within the context of the other available techniques for defect studies. The strengths and weaknesses of PAS as a method for the characterization of defect microstructures are considered. The additional possibilities for using the positron as a localized probe of the atomic and electronic structures of atomic defects are discussed, based upon theoretical calculations of the annihilation characteristics of defect-trapped positrons and experimental observations. Finally, the present status and future potential of PAS as a tool for the study of defects in metals is considered. 71 references, 9 figures.

Download or read book Resolvability of Defect Ensembles with Positron Annihilation Studies written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent advances in the use of positron annihilation to study defect ensembles in and on the surfaces of metals, are pointing the way towards studies where particular positron-electron annihilation modes may be identified and studied in the presence of one another. Although a great deal is understood about the annihilation of positrons in ostensibly defect-free metals, much less is understood when the positron annihilates in complex defect systems such as liquid metals, amorphous solids, or at or near the vacuum-solid interface. In this paper the results of three experiments, all of which demonstrate means by which we can resolve various poistron annihilation channels from one another, are discussed.

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 Positron annihilation Spectroscopy of Defects in Metals written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Positron annihilation spectroscopy (PAS) has made significant contributions to our knowledge regarding lattice defects in metals in two areas: (i) the determination of atomic defect properties, particularly those of monovacancies, and (ii) the monitoring and characterization of vacancy-like microstructure development during post-irradiation of post-quench annealing. The application of PAS to the study of defects in metals is selectively reviewed and critically assessed within the context of other available techniques for such investigations. Possibilities for using the positron as a localized probe of the structure of atomic defects are discussed. Finally, the present status and future potential of PAS as a tool for the study of defects in metals are considered relative to other available techniques. 92 references, 20 figures.

Download or read book Positrons in Solids written by P. Hautojärvi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: In condensed matter initially fast positrons annihilate after having reached equi librium with the surroundings. The interaction of positrons with matter is governed by the laws of ordinary quantum mechanics. Field theory and antiparticle properties enter only in the annihilation process leading to the emergence of energetic photons. The monitoring of annihilation radiation by nuclear spectroscopic methods provides valuable information on the electron-positron system which can directly be related to the electronic structure of the medium. Since the positron is a positive electron its behavior in matter is especially interesting to solid-state and atomic physi cists. The small mass quarantees that the positron is really a quantum mechanical particle and completely different from any other particles and atoms. Positron physics started about 25 years ago but discoveries of new features in its interac tion with matter have maintained continuous interest and increasing activity in the field. Nowadays it is becoming part of the "stock-in-trade" of experimental physics.

Download or read book Metallurgical Studies with Positrons written by and published by . This book was released on 1980 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research performed under these Grants involved the development and application of the positorn annihilation technique to defect studies in metals. The experiments performed during the last three years divide into three categories: (a) the study of the applicability of the simple trapping model to positron annihilation in pure lead as a function of temperature; (b) the study of vacancy-impurity interactions in Pb(Cd) and Pb(Tl) alloys, in order to test the excitonic model of 'fast diffusion' of some impurities in Pb; and (c) the design and testing of multidetector angular correlation setup to perform momentum density measurements in metals with hydrogen, in order to study the role of hydrogen in the electronic structure of pure metals.

Download or read book Influence of Lattice Defects on Positron Annihilation in Metals written by Barry T. A. McKee and published by . This book was released on 1967 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Use of Positron Annihilation to Study Vacancies Defects and Dislocations in Metals written by C.F. Coleman and published by . This book was released on 1975 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Resolution of Lattice Defects in Metals by Positron Annihilation written by and published by . This book was released on 1981 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Defects and Diffusion in Metals 2003 written by David J. Fisher and published by Trans Tech Publications Ltd. This book was released on 2008-07-03 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: This tenth volume in the series covering the latest results in the field includes abstracts of papers which appeared between the publication of Annual Retrospective IX (Volume 265) and the end of May 2008 (journal availability permitting). As well as the 452 metals abstracts, the issue includes – in line with the new editorial policy of including original papers on all of the major material groups: “Defect Investigation of Plastically Deformed Al 5454 Wrought Alloy Using PADBS and Electrical Measurements” (Abdel-Rahman, Kamel, Lotfy, Badawi and Abdel-Rahman), “Activation Enthalpy of Dislocation Migration in Aircraft (Aerospace) (2024) Alloy by Positron Spectroscopy” (Abdel-Rahman, Abdallah, Hassan and Badawi), “Effect of Irradiation Dose on AlCu6.5 Alloy using Positron Annihilation Doppler Broadening Technique” (Abdel-Rahman, Lotfy, Abdel-Rahman and Badawi), “Dependence of Mono-Vacancy Formation Energy on the Parameter of Ashcroft's Potential” (Ghorai), “X-Ray Characterization of Ag Impurities in Na1-xAgxCl” (Hazeen, Syed Ali, Prema Rani and Saravanan), “Self-Organization Behavior of Sub-Micron CdO Grains Grown during Vapour-Solid Transition” (Zhang, Wang and Li), “Studies of the Local Structure and the Spin Hamiltonian Parameters for Co2+ in CaTiO3” (Lu, Wu, Zhang and Wei).

Download or read book Investigation of Defects in Deformed Metals by Positron Annihilation Technique written by B. Nielsen and published by . This book was released on 1978 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Report written by Bent Nielsen and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of defects in deformed metals by positron annihilation technique written by B. Nielsen and published by . This book was released on 1978 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: