Simulations of Currents in X-Band Accelerator Structures Using 2D and 3D Particle-in-Cell Code

Simulations of Currents in X-Band Accelerator Structures Using 2D and 3D Particle-in-Cell Code PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5

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Book Description
Accelerating gradient is one of the crucial parameters affecting design, construction and cost of next-generation linear accelerators. For a specified final energy, the gradient sets the accelerator length, and for a given accelerating structure and pulse repetition rate it determines power consumption. Accelerating gradients on the order of 100 MV/m have been reached in short ((almost equal to) 20cm) standing wave and traveling wave X-band accelerating structures [1, 2, 3]. But recent experiments have shown damage to traveling wave accelerating structures at gradients as low as 50 MV/m after 1000 hours of operation [4]. RF breakdown is a probable cause of this damage. An extensive experimental and theoretical program to determine a safe operating gradient for the Next Linear Collider (NLC) is under way in SLAC. The present work is a part of that program.

Simulations of Currents in X-Band Accelerator Structures Using 2D and 3D Particle-in-Cell Code

Simulations of Currents in X-Band Accelerator Structures Using 2D and 3D Particle-in-Cell Code PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5

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Book Description
Accelerating gradient is one of the crucial parameters affecting design, construction and cost of next-generation linear accelerators. For a specified final energy, the gradient sets the accelerator length, and for a given accelerating structure and pulse repetition rate it determines power consumption. Accelerating gradients on the order of 100 MV/m have been reached in short ((almost equal to) 20cm) standing wave and traveling wave X-band accelerating structures [1, 2, 3]. But recent experiments have shown damage to traveling wave accelerating structures at gradients as low as 50 MV/m after 1000 hours of operation [4]. RF breakdown is a probable cause of this damage. An extensive experimental and theoretical program to determine a safe operating gradient for the Next Linear Collider (NLC) is under way in SLAC. The present work is a part of that program.

Investigations on rf breakdown phenomenon in high gradient accelerating structures

Investigations on rf breakdown phenomenon in high gradient accelerating structures PDF Author: Jiahang Shao
Publisher: Springer
ISBN: 9811079269
Category : Science
Languages : en
Pages : 142

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Book Description
This book mainly focuses on the experimental research of rf breakdown and field emission with novel methods, including triggering rf breakdown with high intensity laser and pin-shaped cathodes as well as locating field emitters with a high resolution in-situ imaging system. With these methods, this book has analyzed the power flow between cells during rf breakdown, observed the evolution of field emission during rf conditioning and the dependence of field emission on stored energy, and studied the field emitter distribution and origination. The research findings greatly expand the understanding of rf breakdown and field emission, which will in turn benefit future study into electron sources, particle accelerators, and high gradient rf devices in general.

Advanced Accelerator Concepts

Advanced Accelerator Concepts PDF Author: Christopher E. Clayton
Publisher: American Institute of Physics
ISBN:
Category : Medical
Languages : en
Pages : 952

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Book Description
The 10th Workshop on Advanced Accelerator Concepts reviews the current progress in the rapidly growing field of advanced accelerators. This series of DOE-sponsored workshops attracts researchers who invent and explore the physics and technologies needed to generate, accelerate, and manipulate particles with plasmas, laser and particle beams, as well as RF and mm-waves. Applications include advanced radiation sources and high energy physics.

High Energy Density and High Power RF

High Energy Density and High Power RF PDF Author: Steven H. Gold
Publisher: American Institute of Physics
ISBN:
Category : Science
Languages : en
Pages : 460

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Book Description
This is the sixth in a series of international workshops on high-power and high-energy density microwave devices for accelerator, plasma physics, and defense applications. Past workshops were held in Dubna, Montauk, Hayama, Pajaro Dunes, and Snowbird. The theme is research and development of techniques to increase microwave energy density and peak power in active and passive microwave devices and components ranging from L-band to W-band. The scope of this workshop has now been broadened to include radar and high power microwave (HPM) systems, space exploration, neutron sources, and even plasma heating and current drive in controlled thermonuclear fusion research.

High Gradient RF Breakdown Studies

High Gradient RF Breakdown Studies PDF Author: Lisa Leanne Laurent
Publisher:
ISBN:
Category :
Languages : en
Pages : 444

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Handbook of Accelerator Physics and Engineering

Handbook of Accelerator Physics and Engineering PDF Author: Alexander Wu Chao
Publisher: World Scientific
ISBN: 9814415855
Category : Science
Languages : en
Pages : 849

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Book Description
Edited by internationally recognized authorities in the field, this expanded and updated new edition of the bestselling Handbook, containing more than 100 new articles, is aimed at the design and operation of modern particle accelerators. It is intended as a vade mecum for professional engineers and physicists engaged in these subjects. With a collection of more than 2000 equations, 300 illustrations and 500 graphs and tables, here one will find, in addition to the common formulae of previous compilations, hard-to-find, specialized formulae, recipes and material data pooled from the lifetime experience of many of the world''s most able practitioners of the art and science of accelerators.The eight chapters include both theoretical and practical matters as well as an extensive glossary of accelerator types. Chapters on beam dynamics and electromagnetic and nuclear interactions deal with linear and nonlinear single particle and collective effects including spin motion, beam-environment, beam-beam, beam-electron, beam-ion and intrabeam interactions. The impedance concept and related calculations are dealt with at length as are the instabilities associated with the various interactions mentioned. A chapter on operational considerations includes discussions on the assessment and correction of orbit and optics errors, real-time feedbacks, generation of short photon pulses, bunch compression, tuning of normal and superconducting linacs, energy recovery linacs, free electron lasers, cooling, space-charge compensation, brightness of light sources, collider luminosity optimization and collision schemes. Chapters on mechanical and electrical considerations present material data and important aspects of component design including heat transfer and refrigeration. Hardware systems for particle sources, feedback systems, confinement and acceleration (both normal conducting and superconducting) receive detailed treatment in a subsystems chapter, beam measurement techniques and apparatus being treated therein as well. The closing chapter gives data and methods for radiation protection computations as well as much data on radiation damage to various materials and devices.A detailed name and subject index is provided together with reliable references to the literature where the most detailed information available on all subjects treated can be found.

Experimental Studies of Internal Dark Currents in High Gradient Accelerator Structures at 17 GHz

Experimental Studies of Internal Dark Currents in High Gradient Accelerator Structures at 17 GHz PDF Author: Haoran Xu (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 180

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Book Description
This thesis presents the measurement of the internal dark current in normal conducting single cell standing wave disk-loaded waveguide (DLWG) accelerator structures that operate at 17 GHz, and its comparison with theory. Dark current is the unwanted current of electrons generated by field emission, multipactor on the accelerator inner surfaces, or both. It is in distinction from the primary beam propagating along the accelerator axis. Dark current that propagates to the ends of the accelerator has been extensively studied, but this is the first detailed study of the internal dark current generated at the structure sidewalls by multipactor. Theoretical calculations indicate that the collision of electrons on the accelerator sidewall will lead to secondary electron emission and subsequent resonant multipactor discharges. Simulations of the multipactor modes were carried out with both our inhouse particle tracking code and with the commercial CST PIC code. Multipactor modes of different orders were predicted to appear at the sidewall with increasing acceleration gradient. The first tested cavities were fabricated from copper and had a sidewall that was either uncoated or coated with diamond-like carbon or titanium nitride. The dark current was measured by a downstream current monitor and by current monitors behind two thin slits opened on the cavity sidewall. With increasing gradient, the downstream dark current increased monotonically, as expected for field emission. The variation of the internal, side dark current was not monotonic but showed the onset of peaks at gradients near 45 and 65 MV/m, in good agreement with simulations using the CST code as well as the in-house code. These were identified as the N = 2 and N = 1 single surface one-point multipactor resonances. The total internal dark current was estimated at ~15 - 30 A. The coated sidewall cavities showed the same multipactor resonances as the uncoated structure. A second set of tests was conducted with a structure with an axisymmetric elliptical central cell sidewall, which was predicted to suppress the internal dark current. After conditioning with 2.2×105 pulses to 93 MV/m, the multipactor modes were completely suppressed and no multipactor resonances were observed. Studies of internal dark current may help to understand the rf conditioning and the ultimate breakdown performance of high gradient rf accelerator structures.

Electrical & Electronics Abstracts

Electrical & Electronics Abstracts PDF Author:
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 1860

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Science Abstracts

Science Abstracts PDF Author:
Publisher:
ISBN:
Category : Electrical engineering
Languages : en
Pages : 1360

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Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 438

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