Thermionic Electron Sources

A survey of the emission characteristics of modern thermionic electron sources is presented. In addition to a discussion of recent advances among the more commonly used emitters such as oxide cathodes, thoriated cathodes, and metal c thodes, a tabulation of the thermionic properties of over one hundred various new matrix and refractory-coated cathodes is given. (Author).

Electrostatic Accelerators have been at the forefront of modern technology since the development by Sir John Cockroft and Ernest Walton in 1932 of the first accelerator, which was the first to achieve nuclear transmutation and earned them the Nobel Prize in Physics in 1951. The applications of Cockroft and Walton's development have been far reaching, even into our kitchens where it is employed to generate the high voltage needed for the magnetron in microwave ovens. Other electrostatic accelerator related Nobel prize winning developments that have had a major socio-economic impact are; the electron microscope where the beams of electrons are produced by an electrostatic accelerator, X-rays and computer tomography (CT) scanners where the X-rays are produced using an electron accelerator and microelectronic technology where ion implantation is used to dope the semiconductor chips which form the basis of our computers, mobile phones and entertainment systems. Although the Electrostatic Accelerator field is over 90 years old, and only a handful of accelerators are used for their original purpose in nuclear physics, the field and the number of accelerators is growing more rapidly than ever. The objective of this book is to collect together the basic science and technology that underlies the Electrostatic Accelerator field so it can serve as a handbook, reference guide and textbook for accelerator engineers as well as students and researchers who work with Electrostatic Accelerators.

This book gives an overview of modern cathodes and electron emitters for vacuum tubes and vacuum electron devices in general. It covers the latest developments in field emission theory as well as new methods towards improving thermionic and cold cathodes. It addresses thermionic cathodes, such as oxide cathodes, impregnated and scandate cathodes, as well as photocathodes and field emitters – the latter comprising carbon nanotubes, graphene and Spindt-type emitter arrays. Despite the rise and fall of the once dominant types of vacuum tubes, such as radio valves and cathode ray tubes, cathodes are continually being improved upon as new applications with increased demands arise, for example in electron beam lithography, high-power and high-frequency microwave tubes, terahertz imaging and electron sources for accelerators. Written by 17 experts in the field, the book presents the latest developments in cathodes needed for these applications, discussing the state of the art and addressing future trends.

Electron microscopy has revolutionized our understanding the extraordinary intellectual demands required of the mi of materials by completing the processing-structure-prop croscopist in order to do the job properly: crystallography, erties links down to atomistic levels. It now is even possible diffraction, image contrast, inelastic scattering events, and to tailor the microstructure (and meso structure ) of materials spectroscopy. Remember, these used to be fields in them to achieve specific sets of properties; the extraordinary abili selves. Today, one has to understand the fundamentals ties of modem transmission electron microscopy-TEM of all of these areas before one can hope to tackle signifi instruments to provide almost all of the structural, phase, cant problems in materials science. TEM is a technique of and crystallographic data allow us to accomplish this feat. characterizing materials down to the atomic limits. It must Therefore, it is obvious that any curriculum in modem mate be used with care and attention, in many cases involving rials education must include suitable courses in electron mi teams of experts from different venues. The fundamentals croscopy. It is also essential that suitable texts be available are, of course, based in physics, so aspiring materials sci for the preparation of the students and researchers who must entists would be well advised to have prior exposure to, for carry out electron microscopy properly and quantitatively.

This groundbreaking text has been established as the market leader throughout the world. Profusely illustrated, the book provides the necessary instructions for successful hands-on application of this versatile materials characterization technique.

Coherent Electron Microscopy: Designing Faster and Brighter Electron Sources, Volume 227 in the Advances in Imaging and Electron Physics series, merges two long-running serials, Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. Chapters in this new release cover Characterization of nanomaterials properties using FE-TEM, Cold field-emission electron sources: From higher brightness to ultrafast beams, Every electron counts: Towards the development of aberration optimized and aberration corrected electron sources, and more. The series features articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science, digital image processing, electromagnetic wave propagation, electron microscopy and the computing methods used in all these domains. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Advances in Imaging and Electron Physics series