A systems study of an RF power source for a 1 TeV next linear collider based upon the relativistic-klystron two-beam accelerator

Abstract

Abstract.A systems study, including physics, engineering and costing, has been conducted to assess the feasibility of a relativistic-klystron two-beam-accelemmr-(RK-TBA) system as a RF power source candidate for a 1 TeV linear collider. Several key issues associated with a realizable RK-TBA system have been addressed, and corresponding schemes have been developed and examined quantitatively. A point design example has been constructed to present a concrete conceptual design which has acceptable transverse and longitudinal beam stability properties. The overall efficiency of RF production for such a power source is estimated to be 36%, and the cost of the full system is estimated to be less than 1 billion dollars. OVERVIEW TBA IssuesAs a power source for linear colliders. The main advantage of .wo-beamaccelerator (1) is high efficiency for drive-beam to rf power conversion. Experimentally, very high peak powers have been achieved in free-electron-laser (2) and relativistic-klystron (3) devices. The basic concept of reacceleration was demonstrated in recent experiments at LLNL (4).These experimental successors not withstanding, several critical issues must be addressed if two-beam accelerators are to be viable as practical power sources for future linear colliders.The general concerns about relativistic-klystron two-beam accelerators (5) (RK-TBA) as a realizable power source evolve around 3 issues: * Work supported in part

Beam dynamics experiments to study the suppression of transverse instabilities

“…This asymmetry in growth has been noted by the authors in simulations for a wide variety of accelerator parameters including full scale RK's [3].…”

“…The asymmetric growth of power about 360 phase advance is a characteristic feature of the betatron node scheme observed in simulations for several different configurations [3].…”

“…The concept was again rediscovered in simulations during a design study of an RK-TBA where the cavities were fortuitously spaced at =2 [3,7]. The main power extraction section of an RK uses strong focusing to transport the beam through small aperture rf output cavities and the beam energy is cyclic with respect to the cavities.…”

“…The RK's strong focusing used to contain the beam in the small aperture resonant structures, repetitive geometry, and reacceleration allows the resonant output structures to be spaced at a betatron phase advance of 360 . Significant theoretical studies and experiments have been accomplished in support of the relativistic klystron two-beam accelerator concept since it was initially described by Sessler and Yu in 1987 [2,3]. The relativistic klystron two-beam accelerator (RTA) program was established at LBNL in 1996 to study engineering and physics issues related to the construction of RK's suitable as rf power sources for TBA applications.…”