A High Efficiency Kinetic Ejection Negative Ion Source For Rib Generation PDF Download
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| Total Pages | : 11 |
| Release | : 1998 |
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Download A High Efficiency, Kinetic-Ejection Negative Ion Source for RIB Generation Book in PDF, ePub and Kindle
Chemically active radioactive species, diffused from RIB target materials, often arrive at the ionization chamber of the source in a variety of molecular forms. Because of the low probability for simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecules with conventional hot-cathode electron-impact ion sources, the species of interest are often distributed in several mass channels in the form of molecular side-band beams and consequently, their intensities are diluted. The sputter negative ion beam generation technique offers an efficient means for simultaneously dissociating and ionizing highly electronegative atomic species present in molecular carriers. We have incorporated these principles in the design and fabrication of a kinetic ejection negative ion source and evaluated its potential for generating {sup 17,18}F− beams for the Holifield Radioactive Ion Beam Facility astrophysics research program. The source utilizes Cs beams to bombard condensable fluorine compounds that emanate from a target material, such as Al2O3, and are transported to the cooled inner surface of a conical-geometry cathode where they are adsorbed. The energetic Cs beams efficiently dissociate these molecules and sputter their constituents. Since the work functions of cesiated surfaces are low, highly electronegative species such as fluorine are efficiently ionized in the sputter-injection process. Measured efficiencies for ionizing atomic fluorine, dissociated from condensable compounds that are formed by reactions of SF6 with fibrous Al2O3 material, exceed 6.5%. In this report, we describe the mechanical design features and principles of operation, and present emittance, F− yield and ionization efficiency data derived from off-line, experimental evaluation of the source.
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| Total Pages | : 5 |
| Release | : 2001 |
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Download High-Efficiency Target-Ion Sources for RIB Generation Book in PDF, ePub and Kindle
In this report, emphasis is placed on issues related to selection and design of high-temperature, ion sources that have demonstrated the high ionization efficiency, species versatility, and operational reliability required at ISOL based radioactive ion beam facilities. In designing sources for ISOL applications, careful attention must be given to the following: selecting the most appropriate materials of construction, coupling of the vapor transport system, ion optics, operational parameters, thermal transport properties, emittances, ionization efficiencies and engineering details for safe handling in the high-level radioactivity radiation fields incumbent at such facilities. Included in the article are descriptions and performance data for high temperature, positive (electron-impact and surface-ionization) and negative (kinetic-ejection and surface-ionization) ion sources, as well as, low temperature, batch-mode negative-ion sources, developed for processing long-lived isotopes, that have been principal contributors to recent successes held at the Holifield Radioactive Ion Beam Facility.
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| Release | : 2001 |
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Download Prototype Negative Ion Sources for RIB Generation Book in PDF, ePub and Kindle
Radioactive ion beams (RIBs) of[sup 17]F and[sup 18]F are of interest for investigation of astrophysical phenomena such as the hot CNO cycle and the rp stellar nuclear synthesis processes. In order to generate useful beam intensities of atomic F[sup[minus]], the species must be efficiently and expediently released from the target material, thermally dissociated from fluoride release products during transport to the ionization chamber of the ion source, and efficiently ionized in the source upon arrival. The authors have conceived and evaluated two prototype negative ion sources for potential use for RIB generation: (1) a direct extraction source and (2) a kinetic ejection source. Both sources utilize Cs vapor to enhance F[sup[minus]] formation. The mechanical design features, operational parameters, ionization efficiencies for forming atomic F[sup[minus]] and delay times for transport of F and fluoride compounds for the respective sources are presented. The efficiency[eta] for formation and extraction of F[sup[minus]] for the direct extraction negative ion source is found to be[eta][approximately] 1.0% while the characteristic delay time[tau] for transport of F and fluorides through the source is typically, [eta][approximately] 120s; the analogous efficiencies and delay times for the kinetic ejection negative ion source are, respectively:[eta]=[approximately]3.2% and[tau]=[approximately]70s.
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| Total Pages | : 14 |
| Release | : 1995 |
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Download A High-efficiency Positive (negative) Surface Ionization Source for RIB Generation Book in PDF, ePub and Kindle
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| Total Pages | : 16 |
| Release | : 1995 |
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Download A Positive (negative) Surface Ionization Source Concept for RIB Generation Book in PDF, ePub and Kindle
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| Total Pages | : 19 |
| Release | : 1996 |
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Download A Combination Thermal Dissociation/electron Impact Ionization Source for RIB Generation Book in PDF, ePub and Kindle
The flourishing interest in radioactive ion beams (RIBs) with intensities adequate for astrophysics and nuclear physics research place a premium on targets that will swiftly release trace amounts of short lived radio-nuclei in the presence of bulk quantities of target material and ion sources that have the capability of efficiently ionizing the release products. Because of the low probability of simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecules containing the element of interest with conventional, hot-cathode, electron-impact ion sources, the species of interest is often distributed in several mass channels in the form of molecular sideband beams and, consequently, the intensity is diluted. The authors have conceived an ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high efficiency characteristics of an electron impact ionization source to address these problems. If the concept proves to be a viable option, the source will be used as a complement to the electron beam plasma ion sources already in use at the HRIBF. The design features and principles of operation of the source are described in this article.
| Author | : A. G. Wright |
| Publisher | : Oxford University Press |
| Total Pages | : 639 |
| Release | : 2017 |
| Genre | : Business & Economics |
| ISBN | : 0199565090 |
Download The Photomultiplier Handbook Book in PDF, ePub and Kindle
"Photomultipliers are extremely sensitive light detectors with the capability to detect single photons. In multiplying the charge produced by incident light by up to 100 million times, these devices are essential to a wide range of applications, from medical instrumentation to astronomical observations. This complete and authoritative guide will provide...a deeper understanding of the operating principles of these devices." -- Publisher's description, back cover.
| Author | : H. Ryssel |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 564 |
| Release | : 2012-12-06 |
| Genre | : Science |
| ISBN | : 3642691560 |
Download Ion Implantation: Equipment and Techniques Book in PDF, ePub and Kindle
The Fourth International Conference on Ion Implantation: Equipment and Tech niques was held at the Convention Center in Berchtesgaden, Bavaria, Germany, from September 13 to 17, 1982. It was attended by more than 200 participants from over 20 different countries. Severa1 series of conferences have dealt with the app1ication of ion implantation to semiconductors and other materials (Thousand Oaks, 1970; Garmisch-Partenkirchen, 1971; Osaka, 1974; Warwick, 1975; Bou1der, 1975; Budapest, 1978; and Albany, 1980). Another series of conferences has been devoted to implantation equipment and techniques (S- ford, 1977; Trento, 1978; and Kingston, 1980). This conference was the fourth in the 1atter series. Twe1ve invited papers and 55 contributed papers covered the areas of ion implantation equipment, measuring techniques, and app1ica tions of implantation to metals and semiconductors. A schoo1 on ion implantation was held in connection with the conference, and the 1ectures presented at this schoo1 were pub1ished as Vo1. 10 of the Springer Series in E1ectrophysics under the tit1e Ion Implantation Techniques (edited by H. Rysse1 and H. G1awischnig). During the conference, space was also provided for presentations and demonstrations by manufacturers of ion implantation equipment. Once again, this conference provided a forum for free discussion among implantation specia1ists in industry as we11 as research institutions. Espe cially effective in stimulating a free exchange of information was the daily get-together over free beer at the "Bier Adam". Many people contributed to the success of this conference.
| Author | : Bernhard Wolf |
| Publisher | : CRC Press |
| Total Pages | : 558 |
| Release | : 1995-08-31 |
| Genre | : Technology & Engineering |
| ISBN | : 9780849325021 |
Download Handbook of Ion Sources Book in PDF, ePub and Kindle
The Handbook of Ion Sources delivers the data needed for daily work with ion sources. It also gives information for the selection of a suitable ion source and ion production method for a specific application. The Handbook concentrates on practical aspects and introduces the principle function of ion sources. The basic plasma parameters are defined and discussed. The working principles of various ion sources are explained, and examples of each type of ion source are presented with their operational data. Tables of ion current for various elements and charge states summarize the performance of different ion sources. The problems related to the production of ions of non-gaseous elements are detailed, and data on useful materials for evaporation and ion source construction are summarized. Additional chapters are dedicated to extraction and beam formation, ion beam diagnosis, ion source electronics, and computer codes for extraction, acceleration, and beam transport. Emittance and brilliance are described and space charge effects and neutralization discussed. Various methods for the measurement of current, profile, emittance, and time structure are presented and compared. Intensity limits for these methods are provided for different ion energies. Typical problems related to the operation of ion source plasmas are discussed and practical examples of circuits are given. The influence of high voltage on ion source electronics and possibilities for circuit protection are covered. The generation of microwaves and various microwave equipment are described and special problems related to microwave operation are summarized. The Handbook of Ion Sources is a valuable reference on the subject, of benefit to practitioners and graduate students interested in accelerators, ion implantation, and ion beam techniques.
| Author | : George B. Rybicki |
| Publisher | : John Wiley & Sons |
| Total Pages | : 400 |
| Release | : 2008-09-26 |
| Genre | : Science |
| ISBN | : 352761818X |
Download Radiative Processes in Astrophysics Book in PDF, ePub and Kindle
Radiative Processes in Astrophysics: This clear, straightforward, and fundamental introduction is designed to present-from a physicist's point of view-radiation processes and their applications to astrophysical phenomena and space science. It covers such topics as radiative transfer theory, relativistic covariance and kinematics, bremsstrahlung radiation, synchrotron radiation, Compton scattering, some plasma effects, and radiative transitions in atoms. Discussion begins with first principles, physically motivating and deriving all results rather than merely presenting finished formulae. However, a reasonably good physics background (introductory quantum mechanics, intermediate electromagnetic theory, special relativity, and some statistical mechanics) is required. Much of this prerequisite material is provided by brief reviews, making the book a self-contained reference for workers in the field as well as the ideal text for senior or first-year graduate students of astronomy, astrophysics, and related physics courses. Radiative Processes in Astrophysics also contains about 75 problems, with solutions, illustrating applications of the material and methods for calculating results. This important and integral section emphasizes physical intuition by presenting important results that are used throughout the main text; it is here that most of the practical astrophysical applications become apparent.
