Do you design and build vacuum electron devices, or work with the systems that use them? Quickly develop a solid understanding of how these devices work with this authoritative guide, written by an author with over fifty years of experience in the field. Rigorous in its approach, it focuses on the theory and design of commercially significant types of gridded, linear-beam, crossed-field and fast-wave tubes. Essential components such as waveguides, resonators, slow-wave structures, electron guns, beams, magnets and collectors are also covered, as well as the integration and reliable operation of devices in microwave and RF systems. Complex mathematical analysis is kept to a minimum, and Mathcad worksheets supporting the book online aid understanding of key concepts and connect the theory with practice. Including coverage of primary sources and current research trends, this is essential reading for researchers, practitioners and graduate students working on vacuum electron devices.

Microwave and RF Vacuum Electronic Power Sources

In the CERN SPS proton synchrotron the four accelerating cavities are of the travelling wave structure type. At the 10 GeV/c injection energy the cavities present to the beam an impedance very similar to that of a detuned RLC cavity with the result that strong dipole and quadrupole instabilities occur. The SPS accelerated beam current was limited by the combined action of these two effects to 2.5 X 10/sup 13/ protons which resulted in capture losses increasing with the injected beam intensity. Among the solutions possible for this problem, the RF feedback, which would alleviate both transient beam loading and instability effects, looked to the authors to be the most promising. In such a system the total voltage seen by the beam is reinjected into the feedback cavity via its power amplifier. Without any delay in the system the cavity impedance seen by the beam could be greatly reduced. Unfortunately the long delay in the system severely limits the bandwidth and the RF feedback could hardly correct more than the n = O beam loading component. The authors circumvented this problem by observing that they needed a large gain only in the vicinities of the RF frequencies. Outside these bandsmore » the phase rotation due to the long delay is unimportant if the gain is made low enough. If, in addition, the total delay of the system is made exactly equal to one machine turn, the open loop phase of the feedback system is always zero for each RF frequency. The two ingredients needed to make the RF feedback work for n not too small are therefore a transfer function with comb filter shape and a total delay of one machine turn. In this paper these ingredients are derived.« less

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Reduction of the Apparent Impedance of Wide Band Accelerating Cavities by RF Feedback

Particle accelerators have many important uses in scientific experiments, in industry and in medicine. This paper reviews the variety of technologies which are used to accelerate charged particles to high energies. It aims to show how the capabilities and limitations of these technologies are related to underlying physical principles. The paper emphasises the way in which different technologies are used together to convey energy from the electrical supply to the accelerated particles.

Acceleration technologies for charged particles: an introduction

This paper reviews the main types of r.f. power amplifiers which are, or may be, used for particle accelerators. It covers solid-state devices, tetrodes, inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz. Factors affecting the satisfactory operation of amplifiers include cooling, matching and protection circuits are discussed. The paper concludes with a summary of the state of the art for the different technologies.

RF power generation

The design of a primary electron beam facility at CERN is described. It re-enables the SPS as an electron accelerator, and leverages the development invested in CLIC technology for its injector and as accelerator R&D infrastructure. The facility would be relevant for several of the key priorities in the 2020 update of the European Strategy for Particle Physics, such as an e+e- Higgs factory, accelerator R&D, dark sector physics, and neutrino physics. In addition, it could serve experiments in nuclear physics. The electron beam delivered by this facility would provide access to light dark matter production significantly beyond the targets predicted by a thermal dark matter origin, and for natures of dark matter particles that are not accessible by direct detection experiments. It would also enable electro-nuclear measurements crucial for precise modelling the energy dependence of neutrino-nucleus interactions, which is needed to precisely measure neutrino oscillations as a function of energy. The implementation of the facility is the natural next step in the development of X-band high-gradient acceleration technology, a key technology for compact and cost-effective electron/positron linacs. It would also become the only facility with multi-GeV drive bunches and truly independent electron witness bunches for plasma wakefield acceleration. The facility would be used for the development and studies of a large number of components and phenomena for a future e+e- Higgs and electroweak factory as the first stage of a next circular collider at CERN, and its cavities in the SPS would be the same type as foreseen for such a future collider. The operation of the SPS with electrons would train a new generation of CERN staff on circular electron accelerators. The facility could be made operational in about five years and would operate in parallel and without interference with Run 4 at the LHC.

Conceptual Design Report -- eSPS

This paper describes briefly the main components of a RF power system with the exception of the accelerating cavity. A diagram of a 200 MHz accelerating system is shown. The power for the accelerating cavities is provided by a 500 kW amplifier utilizing 2, 4, 8 and 16 tetrodes or one 500 kW klystron. The terminating load is a 6 m long 6 1/8'' stainless steel coaxial line. High power transmission lines with coaxial and waveguide components are discussed.

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The RF Power Plant of the SPS

To permit electron-positron acceleration in the SPS, a new 200 MHz RF system will be installed. The system consists of 32 single-cell, high Q accelerating cavities, providing a total peak accelerating voltage of 30 MV. Each cavity will be equipped with an RF power amplifier, capable of delivering 60 kW CW or 110 kW pulsed power (pulse length up to 1 second, duty cycle up to 20 %). The power amplifier will be mounted directly on top of the cavity. Since the space in the existing SPS tunnel is very limited, a compact amplifier is needed, requiring special RF circuitry design. Also the choice of material is restricted due to the presence of ionizing radiation in the tunnel. This paper describes the design of the amplifier and presents the test results, obtained on a prototype version.

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W. Herdrich

Papers

The RF Power Plant of the SPS

RF Power Amplifier for the CERN SPS Operating as LEP Injector