Download or read book Luminescence of Phosphors Under Excitation by Ionizing Radiation and Their Use as Soft X ray Detectors written by Joseph Dresner and published by . This book was released on 1958 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phosphors for Radiation Detectors written by Takayuki Yanagida and published by John Wiley & Sons. This book was released on 2022-02-02 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phosphors for Radiation Detector Phosphors for Radiation Detectors Discover a comprehensive overview of luminescence phosphors for radiation detection In Phosphors for Radiation Detection, accomplished researchers Takayuki Yanagida and Masanori Koshimizu deliver a state-of-the-art exploration of the use of phosphors in radiation detection. The internationally recognized contributors discuss the fundamental physics and detector functions associated with the technology with a focus on real-world applications. The book discusses all forms of luminescence phosphors for radiation detection used in a variety of fields, including medicine, security, resource exploration, environmental monitoring, and high energy physics. Readers will discover discussions of dosimeter materials, including thermally stimulated luminescent materials, optically stimulated luminescent materials, and radiophotoluminescence materials. The book also covers transparent ceramics and glasses and a broad range of devices used in this area. Phosphors for Radiation Detection also includes: Thorough introductions to ionizing radiation induced luminescence, organic scintillators, and inorganic oxide scintillators Comprehensive explorations of luminescent materials, including discussions of materials synthesis and their use in gamma-ray, neutron, and charged particle detection Practical discussions of semiconductor scintillators, including treatments of organic-inorganic layered perovskite materials for scintillation detectors In-depth examinations of thermally stimulated luminescent materials, including discussions of the dosimetric properties for photons, charged particles, and neutrons Relevant for research physicists, materials scientists, and electrical engineers, Phosphors for Radiation Detection is an also an indispensable resource for postgraduate and senior undergraduate students working in detection physics.

Download or read book Radioluminescence written by Jan Lindström and published by Linköping University Electronic Press. This book was released on 2021-03-24 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: A phosphor or scintillator is a material that will emit visible light when struck by ionising radiation. In the early days of diagnostic radiology, it was discovered that the radiation dose needed to get an image on a film, could be greatly reduced by inserting a fluorescent layer of a phosphor in direct contact with the film. Thus, introducing the step of converting the ionising radiation to light in a first step. Going forward in time, film has been replaced with photodetectors and there is now a variety of imaging x-ray systems, still based on phosphors and scintillators. There is continuous research going on to optimise between the radiation dose needed and a sufficient image quality. These factors tend to be in opposition to each other. It is a complicated task to optimise these imaging system and new phosphor materials emerges regularly. One of the key factors is the efficiency of the conversion from xrays to light. In this work this is denoted “extrinsic efficiency”. It is important since it largely determines the final dose to the patient needed for the imaging task. Most imaging x-ray detectors are based on phosphor or scintillator types where their imaging performance has been improved through tweaking of various parameters (light guide structure, higher density, light emission spectrum matching to photodetectors, delayed fluorescence quenching etc) One key factor that largely determines the extrinsic efficiency of a specific phosphor is the particle size. Larger particles result in a higher luminance of the phosphor for the same radiation dose as does as a thicker phosphor layer (to a limit). There exists already a battery of models describing various phosphor qualities. However, particle size and thickness have not been treated as a fully independent variables in previous model works. Indirectly, the influence of these parameters is accounted for, but the existing models were either considered too general, containing several complex parameters and factors to cover all kind of cases or too highly specialised to be easily applicable to fluorescent detectors in diagnostic radiology. The aim of this thesis is therefore to describe and assess a simple model denoted the “LAC-model” (after the original authors Lindström and Alm Carlsson), developed for a fluorescent layer using individual sub-layers defined by the particle size diameter. The model is thought to be a tool for quickly evaluating various particle size and fluorescent layer thickness combinations for a chosen phosphor and design. It may also serve as a more intuitive description of the underlying parameters influencing the final extrinsic efficiency. Further tests affirmed the validity of the model through measurements. The LACmodel produced results deviating a maximum of +5 % from luminescence measurements. During the development of the model various assumptions and simplifications were made. One assumption was the absence of a so called “dead layer”. This is a layer supposedly surrounding each particle decreasing the efficiency of converting x-rays to light. It is not completely “dead” as in inactive but is thought to have a reduced efficiency. This phenomenon was struggled with, when historically designing electron beam stimulated phosphors for various applications (i.e. displays, TV tubes etc). There are also articles reporting dead layer influence for x-ray detectors (usually spectrometers i.e. not for imaging). By introducing a dead layer in the LAC-model the effect of the layer was investigated and was found to result in a change of less than 8% for the extrinsic efficiency. It was also noted that sometimes a dead layer effect may emerge at surfaces of a scintillator slab but not necessarily connected to the phosphor particles themselves. Due to differences between phosphor material and the surroundings, an interface effect arose to compete with the process of inherent dead layers of the individual particles. It was found to be mostly negligible for x-rays in the studied energy and material range. However, an effect was shown for electrons as incident ionising radiation which could shed some light on the strangely neglected apparent dead layer created this way. Finally, applications, one involving developing a prototype for checking the light field radiation field coincidence, were evaluated for overall performance and the optimisation level of the applied fluorescent layer. Interesting findings were made during the development process: for the first time to the knowledge of the author, focus shift wandering was quantified in the corresponding movement of the x-ray field edge and a non-trivial discussion on the concept of an apparent light field edge resulted in a modified definition of the same. En fosfor eller scintillator är ett material som avger synligt ljus när det träffas av joniserande strålning. Inom diagnostisk radiologi upptäckte man i ett tidigt skede att stråldosen som behövdes för att få en bild på en röntgenfilm, reducerades kraftigt om man placerade ett fluorescerande skikt, en fosfor, i direkt kontakt med filmen. I nutid har film ersatts med fotodetektorer och det finns nu en mängd olika röntgenbildsystem men som fortfarande är baserade på fosforer och scintillatorer. Det pågår en kontinuerlig forskning för att optimera mellan erforderlig stråldos och en tillräcklig god diagnostisk bildkvalitet. Dessa faktorer tenderar att motverka varandra. Det är en komplicerad uppgift att optimera röntgenbildsystemen och nya fosformaterial dyker ständigt upp. En av de viktiga egenskaperna är fosforns omvandlingseffektivitet från röntgen till ljus. I detta arbete används benämningen ”extrinsisk (yttre) effektivitet". Denna egenskap är viktig eftersom den i stor utsträckning bestämmer den slutliga dosen till patienten som krävs för bilddiagnostiken. De flesta röntgendetektorer är baserade på fosfor- eller scintillatortyper där bildprestanda har förbättrats genom att utveckla olika parametrar (ljusledarstruktur, högre densitet, ljusemissionsspektrum som matchar fotodetektorer, minskad efterlysning etc.). En viktig faktor som i stor utsträckning bestämmer omvandlingseffektiviteten hos en specifik fosfor är partikelstorleken. Större partiklar resulterar i en högre luminescens (mer ljus) från fosforen för samma stråldos. Vilket också gäller för ett tjockare fosforlager (till en viss gräns!). Det finns redan fysikaliska modeller som beskriver olika fosforparametrar men partikelstorlek och fosfortjocklek har dock inte hanterats som fristående variabler i dessa modellarbeten. Istället har deras inverkan modellerats indirekt men det har gjort att de befintliga modellerna kan anses komplexa. De är antingen för generella som medför flera komplexa parametrar och faktorer för att täcka alla tänkbara varianter eller för specialiserade för att kunna tillämpas enkelt på fluorescerande detektorer i diagnostisk radiologi. Syftet med denna avhandling är därför att beskriva och analysera en praktisk modell betecknad ”LAC-modellen” (efter de ursprungliga författarna Lindström och Alm Carlsson). Den är utvecklad för ett fluorescerande block som består av flera underliggande skikt vars tjocklek bestäms av partiklarnas diameter. Avsikten med modellen är att den ska vara ett verktyg för att snabbt utvärdera olika varianter av partikelstorlek och tjockleks-kombinationer för en vald fosfor med i grunden samma design. Experiment har bekräftat modellens giltighet och mätresultat visar att modellresultaten avvek maximalt +5% från luminiscensmätningar. Utvecklingen av modellen krävde olika antaganden och förenklingar. Ett antagande var frånvaron av ett så kallat ”dött lager”. Det är ett skikt som antas omge varje partikel och som därför minskar omvandlingseffektiviteten från röntgen till ljus. Det är dock inte helt "dött" i meningen helt inaktivt men har en mindre förmåga att omvandla röntgen till ljus jämfört med fosforns huvudmaterial. Historisk sett har man försökt åtgärda detta fenomen under lång tid och speciellt för applikationer där man använt sig av elektronstrålar (dvs olika typer av displayer, TV-rör etc.). Just för elektroner har man sett att döda skiktet tenderar att växa med tiden. Det finns också artiklar som rapporterar en påverkan av röntgendetektorers funktion (vanligtvis dock för spektrometrar, dvs inte för avbildning). Genom att införa ett dött skikt i LAC-modellen undersöktes skiktets effekt och visade sig resultera i en förändring på mindre än 8% för effektiviteten. Det noterades också att ibland kan en dödskiktsliknande effekt uppstå vid ytor av ett scintillatorblock men inte nödvändigtvis pga. av själva fosforpartiklarnas ljusomvandlingsegenskaper. Då det uppstår skillnader mellan fosformaterialet och omgivningen får man en s.k. gränsskiktseffekt som s.a.s. konkurrerar med kemiskt döda skiktet på de enskilda partiklarna. De döda skiktens inverkan visade sig i princip försumbara för röntgenbild-detektorer - åtminstone inom det studerade energi- och materialområdet. En tydlig effekt kunde dock noteras för joniserande strålning i form av elektroner. Simuleringarna kunde ge en bättre bild av egenskaperna hos det döda skiktet som skapats på detta sätt. Slutligen utvärderades två applikationer med hjälp av LAC-modellen: en prototyp för kontroll av ljusfältets och strålfältets överenstämmelse i läge och position. Samt en etablerad produkt med samma användningsområde. I båda fallen undersöktes det fluorescerande skiktets optimeringsgrad. Intressanta resultat noterades under utvecklingsprocessen av prototypen: för första gången, så vitt författaren vet, kunde man kvantifiera röntgenrörs s.k. fokusvandring.

Download or read book Phosphor Handbook written by Shigeo Shionoya and published by CRC Press. This book was released on 2018-10-03 with total page 1078 pages. Available in PDF, EPUB and Kindle. Book excerpt: A benchmark publication, the first edition of the Phosphor Handbook set the standard for references in this field. Completely revised and updated, this second edition explores new and emerging fields such as nanophosphors, nanomaterials, UV phosphors, quantum cutters, plasma display phosphors, sol-gel and other wet phosphor preparation techniques, preparation through combustion, bioluminescence phosphors and devices, and new laser materials such as OLED. It also contains new chapters on the applications of phosphors in solid state lighting, photoionization of luminescent centers in insulating phosphors, and recent developments in halide-based scintillators. The handbook provides a comprehensive description of phosphors with an emphasis on practical phosphors and their uses in various kinds of technological applications. It covers the fundamentals, namely the basic principles of luminescence, the principle phosphor materials, and their optical properties. The authors describe phosphors used in lamps, cathode-ray tubes, x-ray, and ionizing radiation detection. They cover common measurement methodology used to characterize phosphor properties, discuss a number of related items, and conclude with the history of phosphor technology and industry.

Download or read book Fundamentals of Phosphors written by William M. Yen and published by CRC Press. This book was released on 2018-10-03 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drawing from the second edition of the best-selling Handbook of Phosphors, Fundamentals of Phosphors covers the principles and mechanisms of luminescence in detail and surveys the primary phosphor materials as well as their optical properties. The book addresses cutting-edge developments in phosphor science and technology including oxynitride phosphors and the impact of lanthanide level location on phosphor performance. Beginning with an explanation of the physics underlying luminescence mechanisms in solids, the book goes on to interpret various luminescence phenomena in inorganic and organic materials. This includes the interpretation of the luminescence of recently developed low-dimensional systems, such as quantum wells and dots. The book also discusses the excitation mechanisms by cathode-ray and ionizing radiation and by electric fields to produce electroluminescence. The book classifies phosphor materials according to the type of luminescence centers employed or the class of host materials used and interprets the optical properties of these materials, including their luminescence characteristics and mechanisms. Placing a strong emphasis on those materials that are important from a practical point of view, the coverage also includes those possessing no possibility for practical use but are important from a theoretical standpoint.

Download or read book Practical Applications of Phosphors written by William M. Yen and published by CRC Press. This book was released on 2018-10-08 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Drawn from the second edition of the best-selling Phosphor Handbook, Practical Applications of Phosphors outlines methods for the production of various phosphors and discusses a broad spectrum of applications. Beginning with methods for synthesis and related technologies, the book sets the stage by classifying and then explaining practical phosphors according to usage. It describes the operating principle and structure of phosphor devices and the phosphor characteristics required for a given device, then covers the manufacturing processes and characteristics of phosphors. The book discusses research and development currently under way on phosphors with potential for practical usage and touches briefly on phosphors that have played a historical role, but are no longer of practical use. It provides a comprehensive treatment of applications including lamps and cathode-ray tubes, x-ray and ionizing radiation, and for vacuum fluorescent and field emission displays and covers inorganic and organic electroluminescence materials. The book also covers phosphors for plasma displays, organic fluorescent pigments, and phosphors used in a variety of other practical applications. Emphasizing the practical and cutting-edge nature of the material included, the editors round out their coverage with a discussion of solid-state and organic laser materials.

Download or read book New Generation of Europium and Terbium Activated Phosphors written by Mihail Nazarov and published by CRC Press. This book was released on 2011-09-02 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book concentrates on the luminescence and structural properties of the new generation of europium and terbium activated phosphors, associated phenomena, and related topics, from basic principles to the most recent discoveries. It summarizes the present state of the art in this rapidly growing field. The authors describe recent developments in the areas of rare earth doped phosphors and of some new materials or well-known materials with improved properties that open up new possibilities. The areas of focus include X-ray phosphors, phosphors for light-emitting devices, emissive displays, and fluorescent lamps. The book comprises theoretical and experimental analysis of various properties of phosphors, research methods and preparation techniques, and some promising applications.

Download or read book Luminescence and Display Phosphors written by Arunachalam Lakshmanan and published by Nova Publishers. This book was released on 2008 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new book highlights the link between the luminescence phenomena of phosphors used in different displays. Both fluorescence (used in display phosphors) and phosphorescence (used in after glow phosphors and storage phosphors) mechanisms and the efforts made in phosphor synthesis to reduce the interference of one on another are dealt with in detail.

Download or read book Radiation Dosimetry Phosphors written by Sanjay J. Dhoble and published by Woodhead Publishing. This book was released on 2022-05-26 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiation Dosimetry Phosphors provides an overview of the synthesis, properties and applications of materials used for radiation dosimetry and reviews the most appropriate phosphor materials for each radiation dosimetry technique. The book describes the available phosphors used commercially for their applications in the medical field for dose measurements. Although radiation dosimetry phosphors are commercially available, continuous efforts have been made by the worldwide research community to develop new materials or improve already existing materials used in different areas with low or high levels of radiation. Moreover, researchers are still working on developing dosimetric phosphors for OSL, ML, LL and RPL dosimetry. This book provides an overall view of the phosphors available, low cost synthesis methods, mechanisms involved, emerging trends and new challenges for the development of emerging materials for radiation dosimetry. It is suitable for those working in academia and R&D laboratories in the discipline of materials science and engineering, along with practitioners working in radiation and dosimetry. Provides the fundamental concepts, historical context and review of current phosphors available for radiation dosimetry Reviews low-cost material methods to synthesize and characterize rare earth doped inorganic phosphors for different kinds of radiation dosimetry techniques Discusses key barriers and potential solutions for enabling commercial realization phosphors for radiation dosimetry applications

Download or read book X Ray Microscopy written by Chris Jacobsen and published by Cambridge University Press. This book was released on 2019-12-19 with total page 594 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete introduction to x-ray microscopy, covering optics, 3D and chemical imaging, lensless imaging, radiation damage, and applications.

Download or read book Phosphors written by Sanjay J. Dhoble and published by CRC Press. This book was released on 2018-05-11 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rare earth–doped luminescent materials play an integral role in modern life because of their tremendous applications ranging from scintillators, color displays, fluorescent lamps, and intensifying screens to dosimetry of ionizing radiations. Written and edited by prominent luminescence researchers, this book details cutting-edge research on luminescence materials and is illustrated throughout with excellent figures and references. It will appeal to anyone involved in luminescence research and its applications, especially advanced undergraduate-, graduate-, and postgraduate-level students of spectroscopy, solid state physics, luminescence, material synthesis, and optical properties and researchers working on the synthesis of optical materials, the characterization of luminescence materials, solid state lighting, radiation dosimetry luminescence, and phosphor applications.

Download or read book Phosphate Phosphors for Solid State Lighting written by Kartik N. Shinde and published by Springer Science & Business Media. This book was released on 2012-12-15 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: The idea for this book arose out of the realization that, although excellent surveys and a phosphor handbook are available, there is no single source covering the area of phosphate based phosphors especially for lamp industry. Moreover, as this field gets only limited attention in most general books on luminescence, there is a clear need for a book in which attention is specifically directed toward this rapidly growing field of solid state lighting and its many applications. This book is aimed at providing a sound introduction to the synthesis and optical characterization of phosphate phosphor for undergraduate and graduate students as well as teachers and researchers. The book provides guidance through the multidisciplinary field of solid state lighting specially phosphate phosphors for beginners, scientists and engineers from universities, research organizations, and especially industry. In order to make it useful for a wide audience, both fundamentals and applications are discussed, together.

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts written by and published by . This book was released on 1959 with total page 1288 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Luminescence written by Ratnesh Tiwari and published by Walter de Gruyter GmbH & Co KG. This book was released on 2021-12-20 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phosphors are often consisting of transition-metal compounds or rare-earth compounds, with the most common application being displays and fluorescent light. This book will guide the reader through the latest developments in thermo-, electro-, mechano- and bioluminescence of rare earth phosphors and crystals. Also, the effect of doping will be discussed.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Papers on Phosphors Light Emitting Diodes and Scintillators written by Marvin J. Weber and published by SPIE-International Society for Optical Engineering. This book was released on 1998 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains a selection of papers focusing on phosphors, light emitting diodes, and scintillators.