High-Z Nanoparticle/Polymer Nanocomposites for Gamma-Ray Scintillation Detectors PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download High-Z Nanoparticle/Polymer Nanocomposites for Gamma-Ray Scintillation Detectors PDF full book. Access full book title High-Z Nanoparticle/Polymer Nanocomposites for Gamma-Ray Scintillation Detectors by Chao Liu. Download full books in PDF and EPUB format.
Author: Chao Liu Publisher: ISBN: Category : Languages : en Pages : 184
Book Description
An affordable and reliable solution for spectroscopic gamma-ray detection has long been sought after due to the needs from research, defense, and medical applications. Scintillators resolve gamma energy by proportionally converting a single high-energy photon into a number of photomultiplier-tube-detectable low-energy photons, which is considered a more affordable solution for general purposes compared to the delicate semiconductor detectors. An ideal scintillator should simultaneously exhibit the following characteristics: 1) high atomic number (Z) for high gamma stopping power and photoelectron production; 2) high light yield since the energy resolution is inversely proportional to the square root of light yield; 3) short emission decay lifetime; and 4) low cost and scalable production. However, commercial scintillators made from either inorganic single crystals or plastics fail to satisfy all requirements due to their intrinsic material properties and fabrication limitations. The concept of adding high-Z constituents into plastic scintillators to harness high Z, low cost, and fast emission in the resulting nanocomposite scintillators is not new in and of itself. Attempts have been made by adding organometallics, quantum dots, and scintillation nanocrystals into the plastic matrix. High-Z organometallics have long been used to improve the Z of plastic scintillators; however, their strong spin-orbit coupling effect entails careful triplet energy matching using expensive triplet emitters to avoid severe quenching of the light yield. On the other hand, reported quantum dot- and nanocrystal-polymer nanocomposites suffer from moderate Z and high optical loss due to aggregation and self-absorption at loadings higher than 10 wt%, limiting their potential for practical application. This dissertation strives to improve the performance of nanoparticle-based nanocomposite scintillators. One focus is to synthesize transparent nanocomposites with higher loadings of high-Z inorganic nanoparticles. A facile single-precursor method is first developed to synthesize HfO2 nanoparticles, the highest-Z simple oxide with band gap larger than polyvinyltoluene, with uniform size distribution around 5 nm. A nanoparticle-surface-modification protocol is then developed for the fabrication of transparent nanocomposite monoliths with high nanoparticle loadings (up to 40 wt%). Using this method, transparent HfO2-loaded blue-emitting nanocomposite scintillators (2 mm thick, transmittance at 550 nm >75%) have been fabricated capable of producing a full energy photopeak for 662 keV gamma rays, with the best deconvoluted photopeak energy resolution
Author: Chao Liu Publisher: ISBN: Category : Languages : en Pages : 184
Book Description
An affordable and reliable solution for spectroscopic gamma-ray detection has long been sought after due to the needs from research, defense, and medical applications. Scintillators resolve gamma energy by proportionally converting a single high-energy photon into a number of photomultiplier-tube-detectable low-energy photons, which is considered a more affordable solution for general purposes compared to the delicate semiconductor detectors. An ideal scintillator should simultaneously exhibit the following characteristics: 1) high atomic number (Z) for high gamma stopping power and photoelectron production; 2) high light yield since the energy resolution is inversely proportional to the square root of light yield; 3) short emission decay lifetime; and 4) low cost and scalable production. However, commercial scintillators made from either inorganic single crystals or plastics fail to satisfy all requirements due to their intrinsic material properties and fabrication limitations. The concept of adding high-Z constituents into plastic scintillators to harness high Z, low cost, and fast emission in the resulting nanocomposite scintillators is not new in and of itself. Attempts have been made by adding organometallics, quantum dots, and scintillation nanocrystals into the plastic matrix. High-Z organometallics have long been used to improve the Z of plastic scintillators; however, their strong spin-orbit coupling effect entails careful triplet energy matching using expensive triplet emitters to avoid severe quenching of the light yield. On the other hand, reported quantum dot- and nanocrystal-polymer nanocomposites suffer from moderate Z and high optical loss due to aggregation and self-absorption at loadings higher than 10 wt%, limiting their potential for practical application. This dissertation strives to improve the performance of nanoparticle-based nanocomposite scintillators. One focus is to synthesize transparent nanocomposites with higher loadings of high-Z inorganic nanoparticles. A facile single-precursor method is first developed to synthesize HfO2 nanoparticles, the highest-Z simple oxide with band gap larger than polyvinyltoluene, with uniform size distribution around 5 nm. A nanoparticle-surface-modification protocol is then developed for the fabrication of transparent nanocomposite monoliths with high nanoparticle loadings (up to 40 wt%). Using this method, transparent HfO2-loaded blue-emitting nanocomposite scintillators (2 mm thick, transmittance at 550 nm >75%) have been fabricated capable of producing a full energy photopeak for 662 keV gamma rays, with the best deconvoluted photopeak energy resolution
Author: Hongxiang Zhao Publisher: ISBN: Category : Languages : en Pages : 117
Book Description
Spectroscopic scintillation detectors for gamma rays are desirable for medical imaging and nuclear non-proliferation. Thanks to their high-Z nature, inorganic single crystals are commonly used, despite their high cost and limited size. Inexpensive, high performance spectroscopic scintillators are in demand and recently polymer-matrix nanocomposites have become one of the most promising candidates. Nanocomposite used here is mostly two-phase solid where one phase is inorganic nanoparticles with sizes below 20 nm and the other is polymer matrix. Nanocomposites loaded with high-Z, large band gap nanoparticles and luminescent quantum dots have been developed; however, transmittance at its emission wavelength decreased drastically as loading content and sample thickness increased. Monoliths loaded with large band gap high-Z nanoparticles suffered from light yield deterioration due to inefficient non-radiative energy transfer to the polymer matrix. Cadmium zinc sulfide quantum dots improved F rster resonance energy transfer (FRET) from generated excitons to organic species due to their luminescence properties. However the low-Z nature of these quantum dots barely provided noticeable photopeak signals on the pulse height spectrum. This dissertation strives to overcome the obstacles researchers encountered in the field of spectroscopic scintillation study. One focus is to find a new luminescent quantum dot with high Z to improve the photopeak signal of the detector. Inorganic lead halide perovskite nanocrystals have been shown to have high photoluminescence quantum yield (PLQY), fast emission decay, facile size control and most importantly, high Z (ZPb = 82 and ZCs = 55). Cesium lead bromide perovskite nanocrystals were synthesized at a mild temperature, with a square shape capped with oleic acid as the ligand. Ligand exchange of nanocrystals was performed to alleviate phase separation during the in-situ copolymerization with the monomers. Thermal curing was first conducted, yet only produced an opaque monolith. UV curing of the nanocomposites, on the other hand, led to a much more transparent monolith, suggesting instability of the nanocrystals at the elevated temperature. Different organic primary dyes were mixed with the nanocrystals and the monomers, and the resulting solutions were cured to form nanocomposite scintillators. However, all dyes got bleached in the presence of the nanocrystals under UV irradiation. Pulse height spectrum of nanocomposites loaded with perovskite nanocrystals was recorded. The light yield was rather low, and no full gamma photopeak was observed. Liquid matrix was then chosen to substitute polymer matrix in the nanocomposites and scintillation solution can be prepared without polymerization. Cesium lead bromide perovskite nanocrystals were synthesized and purified following the previous protocol, without treatment by polymerizable ligand. The primary dye concentration was adjusted in a broad range, from 0.01 to 1.5 wt%, to study non-radiative energy transfer from perovskite nanocrystals to the dye molecules. Highest light yield of around 10000 photons/MeV was achieved on the liquid scintillator loaded with 20 wt% of nanocrystals at optimized organic dye concentration. Nanocrystal loading was then increased to 60 wt%. In our best demonstration, light yield around 9000 photons/MeV and deconvoluted photopeak energy resolution of 10.6% were achieved with a much more prominent gamma photopeak signal, showing potential of the high-Z luminescent perovskite nanocrystals for spectroscopic scintillators. The obtained photopeak energy resolution was lower than that obtained from the CdZnS-quantum-dot-based nanocomposite scintillators. Many causes for the lower energy resolution were examined. One of the important reasons is that the scintillation emission spectrum from the perovskite liquid scintillators peaks in the green wavelength range where the photodetection efficiency of the photomultiplier tube (PMT) is low. The light yield produced from the PMT is low, and thus the gamma photoelectron energy resolution is low. Scintillation solution loaded with hafnium oxide nanoparticles emitting blue light was then prepared. At 50 wt% loading of the nanoparticles, the transmittance at the emission peak wavelength is still higher than 80%. At 40 wt% loading, the scintillation solution showed light yield of around 6300 photons/MeV with deconvoluted photopeak resolution of 5.3%. Solvent additives were added to the system for more efficient exciton energy transfer from the primary solvent to the primary dye and 25 wt% of naphthalene improved light yield by about 40%. Finally, a large liquid scintillator (20 mm diameter and 20 mm thickness) was prepared containing 40 wt% of nanocrystals as well as solvent additives. Light yield of 8500 photons/MeV and photopeak resolution of 11.6% were achieved. Although there is still room for energy resolution improvement, for the first time we observed a prominent gamma photopeak with an organic liquid scintillator loaded with high-Z nanoparticles.
Author: Hao Yu Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Fast scintillators with spectroscopic gamma response are essential in nuclear security and medical imaging. However, few individual scintillation materials exhibit both fast scintillation decay and excellent photopeak energy resolution. This dissertation strives to develop organic scintillators for fast spectroscopic gamma detection. The focus is to load high-Z nanoparticles (NPs) into plastics and liquids. A nanocomposite plastic scintillator comprising 40 wt% hafnium oxide nanoparticles uniformly dispersed in a luminescent plastic matrix is synthesized. The nanoparticles have an average diameter of 4.2 nm and are covalently attached to the polymer matrix to prevent agglomeration. A progressive curing protocol using a low-temperature and a high-temperature initiator is developed to synthesize centimeter-size nanocomposites. The addition of 5 vol% divinylbenzene is key to boosting bulk transmittance, resulting in a measured transmittance of around 80% across the emission range. Gamma pulse scintillation has a fast decay time constant of 2.5 ns and a modest light output of 8,000-9,000 photons/MeV. The gamma scintillation shows energy proportionality from 32 to 1275 keV. A 1.93 cm3 nanocomposite produces photopeaks at 32 and 662 keV for 137Csand at 511 and 1275 keV for 22Na. The photopeak energy resolution at 662 keV is 7.2%-9.1%. While the energy resolution is approaching that of single crystal scintillators, it is negatively impacted by the trade-off between high NP loading and diminishing light output. To address this issue, CsPbBr3 quantum dots (QDs) are loaded into liquid scintillators up to 40 wt%. Pyrromethene 580 (PM-580), a fluorescent dye, is co-dissolved in the solution as a fluorescence resonance energy transfer acceptor to overcome the self-absorption of the QDs. The rapid energy transfer from the QDs to PM-580 also accelerates the scintillation decay kinetics. The decay time constant is 24.3 ns, faster than most inorganic crystal scintillators. The light output is 7,300 photons/MeV at 40 wt% QD loading. Gamma pulse spectroscopy of the 40 wt% QD liquid produces a 662 keV gamma photopeak with a 27% energy resolution, demonstrating the potential of the CsPbBr3 QD loaded organic scintillators for spectroscopic gamma detection.
Author: Sunil Kumar Sahi Publisher: ISBN: Category : Nanocomposites (Materials) Languages : en Pages : 163
Book Description
Inorganic single crystal and organic (plastic and liquid) scintillators are commonly used for radiation detection. Inorganic single crystals are efficient and have better energy resolution compared to organic scintillators. However, inorganic single crystals are difficult to grow in large size and hence expensive. On the other hand, fast decay time and ease of fabrication makes organic scintillators attractive for many applications. However, poor energy resolution of organic scintillators limits its applications in gamma ray spectroscopy. The poor energy resolution is due to the low Z-Value and low density of organic scintillator. The Z-value of organic plastic scintillator can be increase by loading nanoparticles in plastic matrix. It is expected that the increase in Z-value would result in improve energy resolution of nanocomposite scintillator. However, the loss of optical transparency due to nanoparticles loading is one of the major concerns of nanocomposite scintillators. In this dissertation, we used different methods to synthesize LaxCe1-xF3 nanoparticles with high dispersion in polymer matrix. High nanoparticle dispersion is important to load high concentration of nanoparticles into polymer matrix without losing the transparency of the polymer matrix. The as synthesized nanoparticles are dispersed into monomers and polymerized using heat initiated bulk polymerization method. Nanoparticles are characterized using TEM, XRD, FTIR and TGA. The optical and scintillation properties of nanoparticles and nanocomposites are studied using spectroscopic techniques. The pulse height spectra obtained using nanocomposite fabricated by loading up to 30 wt% nanoparticles clearly show a photopeak for the 122 keV line of the Co-57 isotope. The generation of the photopeak is due to the enhanced photoelectric effect as a result of increased effective atomic number (Zeff) and density of nanocomposite scintillator. The pulse height spectra of Cs-137 gamma source show a full energy peak at around 622 keV, due to the escape of La and Ce K[alpha] X-rays. The fabrication process of transparent nanocomposite scintillator is discussed in details.
Author: Matthieu Hamel Publisher: Springer Nature ISBN: 3030734889 Category : Science Languages : en Pages : 647
Book Description
This book introduces the physics and chemistry of plastic scintillators (fluorescent polymers) that are able to emit light when exposed to ionizing radiation, discussing their chemical modification in the early 1950s and 1960s, as well as the renewed upsurge in interest in the 21st century. The book presents contributions from various researchers on broad aspects of plastic scintillators, from physics, chemistry, materials science and applications, covering topics such as the chemical nature of the polymer and/or the fluorophores, modification of the photophysical properties (decay time, emission wavelength) and loading of additives to make the material more sensitive to, e.g., fast neutrons, thermal neutrons or gamma rays. It also describes the benefits of recent technological advances for plastic scintillators, such as nanomaterials and quantum dots, which allow features that were previously not achievable with regular organic molecules or organometallics.
Author: Klaus D. Sattler Publisher: CRC Press ISBN: 1351260553 Category : Science Languages : en Pages : 4153
Book Description
This 21st Century Nanoscience Handbook will be the most comprehensive, up-to-date large reference work for the field of nanoscience. Handbook of Nanophysics, by the same editor, published in the fall of 2010, was embraced as the first comprehensive reference to consider both fundamental and applied aspects of nanophysics. This follow-up project has been conceived as a necessary expansion and full update that considers the significant advances made in the field since 2010. It goes well beyond the physics as warranted by recent developments in the field. Key Features: Provides the most comprehensive, up-to-date large reference work for the field. Chapters written by international experts in the field. Emphasises presentation and real results and applications. This handbook distinguishes itself from other works by its breadth of coverage, readability and timely topics. The intended readership is very broad, from students and instructors to engineers, physicists, chemists, biologists, biomedical researchers, industry professionals, governmental scientists, and others whose work is impacted by nanotechnology. It will be an indispensable resource in academic, government, and industry libraries worldwide. The fields impacted by nanoscience extend from materials science and engineering to biotechnology, biomedical engineering, medicine, electrical engineering, pharmaceutical science, computer technology, aerospace engineering, mechanical engineering, food science, and beyond.
Author: Takayuki Yanagida Publisher: John Wiley & Sons ISBN: 1119583381 Category : Technology & Engineering Languages : en Pages : 593
Book Description
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.
Author: Klaus D. Sattler Publisher: CRC Press ISBN: 1000702545 Category : Science Languages : en Pages : 401
Book Description
This 21st Century Nanoscience Handbook will be the most comprehensive, up-to-date large reference work for the field of nanoscience. Handbook of Nanophysics by the same editor published in the fall of 2010 and was embraced as the first comprehensive reference to consider both fundamental and applied aspects of nanophysics. This follow-up project has been conceived as a necessary expansion and full update that considers the significant advances made in the field since 2010. It goes well beyond the physics as warranted by recent developments in the field. This ninth volume in a ten-volume set covers industiral applications. Key Features: Provides the most comprehensive, up-to-date large reference work for the field. Chapters written by international experts in the field. Emphasises presentation and real results and applications. This handbook distinguishes itself from other works by its breadth of coverage, readability and timely topics. The intended readership is very broad, from students and instructors to engineers, physicists, chemists, biologists, biomedical researchers, industry professionals, governmental scientists, and others whose work is impacted by nanotechnology. It will be an indispensable resource in academic, government, and industry libraries worldwide. The fields impacted by nanophysics extend from materials science and engineering to biotechnology, biomedical engineering, medicine, electrical engineering, pharmaceutical science, computer technology, aerospace engineering, mechanical engineering, food science, and beyond.
Author: Vladimir A. Bershtein Publisher: Springer Nature ISBN: 3031329430 Category : Technology & Engineering Languages : en Pages : 186
Book Description
This book presents an overview of polymer nanocomposites for use in various high-temperature applications. Specifically, it focuses on the structure and physical properties of nanocomposites based on heterocyclic matrices derived from nitrile monomers such as cyanate esters or phthalonitriles. Due to increasing interest in new heat-resistant, lightweight materials for use in extreme conditions, such as in aeronautics, microelectronics, and various industrial machinery, the high thermal stability of heterocyclic polymer networks, in particular, has attracted much attention from materials researchers and engineers. Featuring a comprehensive review of the most recent advances in research on the structure and physical properties of these promising high-temperature polymer nanocomposites, this book will be of particular interest to materials scientists and engineers working throughout the fields of aeronautical and microelectronic engineering. In general, this book is intended for use by researchers of composite materials and specialists engaged in material selection for work in extreme conditions; for students specializing in materials science; for polymer physicists, and for university libraries.
Author: Takayuki Yanagida Publisher: Wiley ISBN: 9781119583325 Category : Technology & Engineering Languages : en Pages : 416
Book Description
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.
Author: Chao Liu
Author: Chao Liu
Author: Hongxiang Zhao
Author: Hao Yu
Author: Sunil Kumar Sahi
Author: Matthieu Hamel
Author: Klaus D. Sattler
Author: Takayuki Yanagida
Author: Klaus D. Sattler
Author: Vladimir A. Bershtein
Author: Takayuki Yanagida