Development of HPGE Detector for the Longitudinal Emittance Measurement PDF Download

Author: Reiko Taki
Publisher:
ISBN:
Category : Beam dynamics
Languages : en
Pages : 170

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Author: Quinn Looker
Publisher:
ISBN:
Category :
Languages : en
Pages : 177

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High-purity germanium (HPGe) radiation detectors are well established as a valuable tool in nuclear science, astrophysics, and nuclear security applications. HPGe detectors excel in gamma-ray spectroscopy, offering excellent energy resolution with large detector sizes for high radiation detection efficiency. Although a robust fabrication process has been developed, improvement is needed, especially in developing electrical contact and surface passivation technology for position-sensitive detectors. A systematic study is needed to understand how the detector fabrication process impacts detector performance and reliability. In order to provide position sensitivity, the electrical contacts are segmented to form multiple electrodes. This segmentation creates new challenges in the fabrication process and warrants consideration of additional detector effects related to the segmentation. A key area of development is the creation of the electrical contacts in a way that enables reliable operation, provides low electronic noise, and allows fine segmentation of electrodes, giving position sensitivity for radiation interactions in the detector. Amorphous semiconductor contacts have great potential to facilitate new HPGe detector designs by providing a thin, high-resistivity surface coating that is the basis for electrical contacts that block both electrons and holes and can easily be finely segmented. Additionally, amorphous semiconductor coatings form a suitable passivation layer to protect the HPGe crystal surface from contamination. This versatility allows a simple fabrication process for fully passivated, finely segmented detectors. However, the fabrication process for detectors with amorphous semiconductors is not as highly developed as for conventional technologies. The amorphous semiconductor layer properties can vary widely based on how they are created and these can translate into varying performance of HPGe detectors with these contacts. Some key challenges include minimizing charge injection leakage current, increasing the long-term stability of the contacts, and achieving good charge collection properties in segmented detectors. A systematic study of contact characteristics is presented where amorphous germanium (a-Ge) and amorphous silicon (a-Si) contacts are sputtered with varying sputter gas hydrogen content, sputter gas pressure, and amorphous film thickness. A set of about 45 detectors fabricated from 11 different crystal samples were analyzed for electron barrier height and effective Richardson constant. Most of these detectors were subjected to as many as 10 temperature cycles over a period of up to several months in order to assess their long-term stability. Additionally, 6 double-sided strip detectors were fabricated with a-Ge and a-Si contacts in order to study their inter-electrode charge collection properties. An attempt is made to relate fabrication process parameters such as hydrogen content, sputter pressure, and film thickness to changes observed in detector performance and assess the level of reproducibility using the current methods. Several important results and conclusions were found that enable more reliable and highly performing detectors with amorphous semiconductor contacts. Utilizing the new information should enable consistent production of finely segmented detectors with excellent energy resolution that can be operated reliably for a long period of time. The passivation process could impact planar detectors as well as other designs, such as the p-type point contact detector. It is demonstrated that the long-term stability of amorphous semiconductor contacts is primarily dependent on the time the detector is at room temperature rather than the number of temperature cycles. For a-Ge contacts, higher sputter pressure yields a more stable process that changes little with time, giving a reliable hole-blocking contact. The a-Si contacts form a good electron-blocking contact with decreasing leakage current over time. Both materials, when 7% hydrogen is included in the argon sputter gas, show acceptable levels of inter-electrode charge collection to be useful for strip electrode detectors.

Author:
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Category :
Languages : en
Pages :

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Author:
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ISBN:
Category :
Languages : en
Pages : 42

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The properties of charged particle beams associated with the distribution of the particles in energy and in time can be grouped together under the category of longitudinal emittance. This article is intended to provide an intuitive introduction to the concepts longitudinal emittance; to provide an incomplete survey of methods used to measure this emittance and the related properties of bunch length and momentum spread; and to describe the detailed design of a 6 Ghz bandwidth resistive wall current monitor useful for measuring bunch shapes of moderate to high intensity beams. Overall, the article is intended to be broad in scope, in most cases deferring details to cited original papers. 37 refs., 21 figs.

Author:
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ISBN:
Category : Power resources
Languages : en
Pages : 792

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Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.

Author: Argonne National Laboratory. Physics Division
Publisher:
ISBN:
Category : Nuclear physics
Languages : en
Pages : 312

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Author: Yican Wu
Publisher: Springer
ISBN: 981105469X
Category : Science
Languages : en
Pages : 402

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This book provides a systematic and comprehensive introduction to fusion neutronics, covering all key topics from the fundamental theories and methodologies, as well as a wide range of fusion system designs and experiments. It is the first-ever book focusing on the subject of fusion neutronics research. Compared with other nuclear devices such as fission reactors and accelerators, fusion systems are normally characterized by their complex geometry and nuclear physics, which entail new challenges for neutronics such as complicated modeling, deep penetration, low simulation efficiency, multi-physics coupling, etc. The book focuses on the neutronic characteristics of fusion systems and introduces a series of theories and methodologies that were developed to address the challenges of fusion neutronics. Further, it introduces readers to the unique principles and procedures of neutronics design, experimental methodologies and methodologies for fusion systems. The book not only highlights the latest advances and trends in the field, but also draws on the experiences and skills collected in the author’s more than 40 years of research. To make it more accessible and enhance its practical value, various representative examples are included to illustrate the application and efficiency of the methods, designs and experimental techniques discussed.

Author:
Publisher:
ISBN:
Category : Physics
Languages : en
Pages : 1162

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Author: C. Barry Carter
Publisher: Springer
ISBN: 3319266519
Category : Technology & Engineering
Languages : en
Pages : 543

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This text is a companion volume to Transmission Electron Microscopy: A Textbook for Materials Science by Williams and Carter. The aim is to extend the discussion of certain topics that are either rapidly changing at this time or that would benefit from more detailed discussion than space allowed in the primary text. World-renowned researchers have contributed chapters in their area of expertise, and the editors have carefully prepared these chapters to provide a uniform tone and treatment for this exciting material. The book features an unparalleled collection of color figures showcasing the quality and variety of chemical data that can be obtained from today’s instruments, as well as key pitfalls to avoid. As with the previous TEM text, each chapter contains two sets of questions, one for self assessment and a second more suitable for homework assignments. Throughout the book, the style follows that of Williams & Carter even when the subject matter becomes challenging—the aim is always to make the topic understandable by first-year graduate students and others who are working in the field of Materials Science Topics covered include sources, in-situ experiments, electron diffraction, Digital Micrograph, waves and holography, focal-series reconstruction and direct methods, STEM and tomography, energy-filtered TEM (EFTEM) imaging, and spectrum imaging. The range and depth of material makes this companion volume essential reading for the budding microscopist and a key reference for practicing researchers using these and related techniques.

Author: Keith F. Eckerman
Publisher: Snmmi
ISBN: 9780932004802
Category : Decay schemes (Radioactivity)
Languages : en
Pages : 684

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