G.K. Merdinian

Bio: G.K. Merdinian is an academic researcher from Varian Associates. The author has contributed to research in topics: Linear particle accelerator & Klystron. The author has an hindex of 2, co-authored 3 publications receiving 10 citations. Previous affiliations of G.K. Merdinian include Stanford University.

Klystrons for the Stanford linear accelerator center

Abstract: A 2-mile-long linear accelerator has been built at Stanford University that uses 245 klystrons to produce an electron beam with an energy up to 20 GeV. Although most of the tubes used are being procured from industry, a major portion of the development work has been and is still being done at Stanford. We will review the important results of this work. In general, the klystrons are designed to produce a minimum of 21 MW peak power with extremely stringent phase and amplitude stability performance requirements. They are focused by permanent magnets and operate up to 250 kV beam voltage with a microperveance of 2. During the past few years, gradual improvements in performance have been achieved by optimizing the bunching parameter and the output cavity coupling, and we have measured efficiencies approaching 45 percent in a permanent magnet. Permanent magnet structure limitations, field shaping, and changes in the klystron design to reduce the magnetic field requirements will be discussed. The output window life has been improved by coating techniques developed to decrease single surface multipactor and reduce window operating temperature. Questions of coating stability will also be discussed. Finally, the paper will touch on the initial results of statistical analysis of tube life as a function of operating experience.

High power permanent magnet focused S-band klystron for linear accelerator use

Abstract: The klystrons needed to power the SLAC two-mile accelerator have nominal power output specifications of 24 Mw peak, 22 kw average. The minimum gain is 50 db and extremely stringent specifications have been imposed on noise and phase stability. The reasons for the selection of permanent-magnet focusing, including both advantages and disadvantages, will be reviewed. The availability of permanent magnet materials and the resultant limitations in maximum field and length resulted in the necessity for some compromises in the tube electrical design. Of particular importance are the field shaping in the gun region, the transverse fields in the gun and interaction region, and the magnetic field in the collector region. The high gain and high power requirements of this klystron resulted in some unexpected oscillations, the solution of which will be discussed. As of now, several klystrons have been tested which achieve between 18 and 21 Mw in permanent magnet at efficiencies of approximately 35%. The comparison of their performance with the performance of the same tube in electromagnets will be discussed.

Klystrons for the Stanford linear accelerator center

Abstract: A two-mile long linear accelerator has been built at Stanford University which uses 245 klystrons to produce an electron beam with an energy up to 20 GeV. Although most of the tubes used are being procured from industry, a major portion of the development work has been, and is still being, done at Stanford. We will review the important results of this work.

High-power linear-beam tubes

Abstract: High-power klystrons, coupled-cavity traveling-wave tubes (TWT's), and hybrid tubes, all of which utilize the microwave cavity as the basic circuit element, are described. These amplifiers are used in communications, radars, electronic countermeasures, and other applications at power levels from a few hundred watts to megawatts, at frequencies from ultrahigh frequency on up, and are particularly suited for high average powers. High gain, 30 to 60 dB, is normally achieved, and bandwidth usually lies in the 1-30-percent range. Elementary theory of operation is described, together with design considerations and systems interface information. Typical tube designs and data are presented. Recent developments are discussed, including high-efficiency techniques (to 75 percent), improvements in bandwidth, periodic focusing, and beam control electrodes. Most of the basic design techniques are well developed, and emphasis is being shifted to improvements in the detailed performance characteristics such as gain and phase resolution ripples, noise, and the sensitivities to operating voltages and currents.

High Power Klystrons

Abstract: This paper will review the evolution of high power klystrons and their applications in supplying rf energy for linear accelerators. Other types of possible rf sources were considered for SLAC, and the reasons for the selection of klystrons will be given. A brief review of klystron types in use for various accelerators will also be given, but the emphasis will be on the work done by Stanford and its subcontractors in developing klystrons capable of achieving peak powers in excess of 20 MW and average powers of 20 kW for use with the two-mile Stanford linear accelerator.

The Intense Neutron Generator and Future Factory Type Ion Accelerators

Abstract: A neutron factory is likely to sell its product in the form of isotopes. Today neutron factories are nuclear reactors. Ion accelerators may also produce isotopes by direct interaction and, at high enough energies, mesons and hyperons. The challenge of the electrical production of neutrons goes far beyond the isotope market. It challenges the two popular concepts for long term large scale energy, the fast breeder reactor and controlled thermonuclear fusion. For this use about 4% of nuclear generated power would be applied in a feedback loop generating extra neutrons. Competition rests on operating and processing costs. The Intense Neutron Generator proposal now cancelled would have been full scaloe for such a use, but much further advance in accelerator engineering is required and anticipated. Perhaps most promising is the application of the ion drag principle in which rings of fast electrons are accelerated along their axis dragging ions with them by electrostatic attraction. Due to the much larger mass of the ions they can acquire much higher energy than the electrons and the process could be efficient. Such accelerators have not yet been made but experimental and theoretical studies are promising.

High-power klystron development at the Stanford linear accelerator center

Abstract: Continuing development of peramanent-magnet-focused high-power klystrons has resulted in achievement of efficiencies in excess of 50% with microperveances greater than 2 at a frequency of 2856 MHz. This paper will discuss the latest advances made in the study of klystrons operating with highly relativistic beams.

Klystrons for the Stanford linear accelerator center

Abstract: A 2-mile-long linear accelerator has been built at Stanford University that uses 245 klystrons to produce an electron beam with an energy up to 20 GeV. Although most of the tubes used are being procured from industry, a major portion of the development work has been and is still being done at Stanford. We will review the important results of this work. In general, the klystrons are designed to produce a minimum of 21 MW peak power with extremely stringent phase and amplitude stability performance requirements. They are focused by permanent magnets and operate up to 250 kV beam voltage with a microperveance of 2. During the past few years, gradual improvements in performance have been achieved by optimizing the bunching parameter and the output cavity coupling, and we have measured efficiencies approaching 45 percent in a permanent magnet. Permanent magnet structure limitations, field shaping, and changes in the klystron design to reduce the magnetic field requirements will be discussed. The output window life has been improved by coating techniques developed to decrease single surface multipactor and reduce window operating temperature. Questions of coating stability will also be discussed. Finally, the paper will touch on the initial results of statistical analysis of tube life as a function of operating experience.