SLED II: A new method of rf pulse compression
01 Sep 1990-pp 10-14
TL;DR: In the Resonant Line SLED (RELS) method as mentioned in this paper, two high Q resonators store energy from an RF source for a relatively long time interval (typically 3 to 5 µsec). Triggered by a reversal in RF phase, this stored energy is then released during a much shorter interval equal to the filling time of the accelerating structure.
Abstract: In the SLED method of RF pulse compression, two high Q resonators store energy from an RF source for a relatively long time interval (typically 3 to 5 {mu}sec). Triggered by a reversal in RF phase, this stored energy is then released during a much shorter interval equal to the filling time of the accelerating structure. A peak power gain on the order of three and a compression efficiency on the order of 60% are typically attained. The shape of the output pulse is, however, a sharply decaying exponential. In SLED-II the two cavities are replaced by two lengths of resonant line, forming a Resonant Line SLED (RELS) and resulting in a flat output pulse. Therefore, RELS stages can be cascaded to give a greater peak power gain. Using two stages, a peak power gain greater than ten can be achieved with a reasonable compression efficiency. Unlike the BEC, the RELS compression factor per stage is not limited to two, albeit at the expense of intrinsic efficiency. Like the BEC, it uses long lines rather than short cavities.
Citations
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TL;DR: Time-resolved measurements of X-ray free-electron lasers are reported by using an X-band radiofrequency transverse deflector at the Linac Coherent Light Source to demonstrate this method to be a simple, non-invasive technique with a large dynamic range for single-shot electron andX-ray temporal characterization.
Abstract: Characterizing femtosecond X-ray pulses that vary from shot to shot is important for data interpretation. Here, Behrens et al. measure time-resolved lasing effects on the electron beam and extract the temporal profile of X-ray pulses using an X-band radiofrequency transverse deflector.
227 citations
TL;DR: In this article, the operating characteristics of a two-cavity X-band gyroklystron experiment are reported, where beam voltages and currents up to 440 kV and 200 A, respectively, are generated in 1 mu s pulses by a thermionic magnetron injection gun.
Abstract: The operating characteristics of a two-cavity X-band gyroklystron experiment are reported. Beam voltages and currents up to 440 kV and 200 A, respectively, are generated in 1 mu s pulses by a thermionic magnetron injection gun. Velocity ratios ( nu /sub perpendicular to // nu /sub z/) near one in the output cavity are used to achieve peak powers of 24 MW near 9.87 GHz. The maximum saturated efficiency of more than 33% occurs at a beam voltage of 425 kV and a current of 150 A. A large signal gain in excess of 34 dB is realized by operating the input cavity just below the start oscillation threshold. Details of tube stability and the dependence of amplification on magnetic field profile, input signal parameters, and various beam quantities are presented. >
63 citations
TL;DR: In this paper, the authors present the design and a proof of principle experimental results of an optically controlled high-power RP pulse-compression system based on the switched resonant delay-line theory.
Abstract: We present the design and a proof of principle experimental results of an optically controlled high-power RP pulse-compression system. In principle, the design should handle a few hundreds of megawatts of power at X-band. The system is based on the switched resonant delay-line theory [1]. It employs resonant delay lines as a means of storing RF energy. The coupling to the lines is optimized for maximum energy storage during the charging phase. To discharge the lines, a high-power microwave switch increases the coupling to the lines just before the start of the output pulse. The high-power microwave switch required for this system is realized using optical excitation of an electron-hole plasma layer on the surface of a pure silicon wafer. The switch is designed to operate in the TE/sub 01/ mode in a circular waveguide to avoid the edge effects present at the interface between the silicon wafer and the supporting waveguide; thus, enhancing its power handling capability.
58 citations
Cites background from "SLED II: A new method of rf pulse c..."
...The SLED II pulse compression system is a variation of SLED that gives a flat output pulse[8]....
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...These two effects make the intrinsic efficiency of SLED II deteriorate very fast at large compression ratios[8]....
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17 May 1993
TL;DR: The NLC Test Accelerator (NLCTA) as discussed by the authors is a testbed for the next linear Collider (NLC) and is designed to address many questions related to the dynamics of the beam during acceleration.
Abstract: During the past several years, there has been tremendous progress on the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse compression systems and damped/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams necessary for an NLC, we are building an NLC Test Accelerator (NLCTA). The goal of the NLCTA is to bring together all elements of the entire accelerating system by constructing and reliably operating an engineered model of a high-gradient linac suitable for the NLC. The NLCTA will serve as a testbed as the design of the NLC evolves. In addition to testing the RF acceleration system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration. In this paper, we will report on the status of the design, component development, and construction of the NLC Test Accelerator. >
44 citations
TL;DR: In this article, a delay line distribution system for the Next Linear Collider (LCLC) design is presented, where the power of several sources is combined into a single waveguide delay line using a multimode launcher.
Abstract: The delay line distribution system is an alternative to conventional pulse compression, which enhances the peak power of rf sources while matching the long pulse of those sources to the shorter filling time of accelerator structures. We present an implementation of this scheme that combines pairs of parallel delay lines of the system into single lines. The power of several sources is combined into a single waveguide delay line using a multimode launcher. The output mode of the launcher is determined by the phase coding of the input signals. The combined power is extracted from the delay line using mode-selective extractors, each of which extracts a single mode. Hence, the phase coding of the sources controls the output port of the combined power. The power is then fed to the local accelerator structures. We present a detailed design of such a system, including several implementation methods for the launchers, extractors, and ancillary high power rf components. The system is designed so that it can handle the 600 MW peak power required by the Next Linear Collider design while maintaining high efficiency.
37 citations
References
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01 Jan 1974
TL;DR: In this paper, it is shown that the accelerator would have to be completely refitted with klystrons producing about 100 MW in order that the present machine energy be approximate doubled.
Abstract: Over the past few years, several schemes for *. making significant increases in the energy of the SLAC beam have been proposed. Two of the proposals, namely the use of superconducting accelerating sections1 and recirculation 1 of the beam for a second pass through the existing acceler. &or,’ have been abandoned for technical and economic reasons after extensive investigation. An on-going method of gradually raising the beam energy is the development and installation of 30and 40-MW klystrons by the SLAC Klystron Group. It is clear, however, that the accelerator would have to be completely refitted with klystrons producing about 100 MW in order that the present machine energy be approximate1 doubled. While such an approach is not inconceivable, 3 the realization of such klystrons and the modulators needed to drive them would require further years of development and a high initial capital investment.
173 citations
TL;DR: A new method of pulse compression, the binary power multiplier (BPM), a device which multiplies RF power in binary steps which doubles the input power and halves the input pulse length is described.
Abstract: This paper describes a new method of pulse compression, the binary power multiplier (BPM), a device which multiplies RF power in binary steps. It comprises one or more stages, each of which doubles the input power and halves the input pulse length. Practical designs are described and expressions for their compression efficiency are derived. The usefulness of pulse compression for accelerator design is illustrated and compared with the pulse compression system currently in use at the Stanford Linear Accelerator Center.
76 citations