High-Power Multimode X-Band RF Pulse Compression System for Future Linear Colliders
07 Apr 2005-Physical Review Special Topics-accelerators and Beams (American Physical Society)-Vol. 8, Iss: 4, pp 042002
TL;DR: In this article, a multimode $X$-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC).
Abstract: We present a multimode $X$-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single NLC rf unit is required to produce 400 ns pulses with 475 MW of peak power. Each rf unit should power approximately 5 m of accelerator structures. The rf unit design consists of two 75 MW klystrons and a dual-moded resonant-delay-line pulse compression system that produces a flat output pulse. The pulse compression system components are all overmoded, and most components are designed to operate with two modes. This approach allows high-power-handling capability while maintaining a compact, inexpensive system. We detail the design of this system and present experimental cold test results. We describe the design and performance of various components. The high-power testing of the system is verified using four 50 MW solenoid-focused klystrons run off a common 400 kV solid-state modulator. The system has produced 400 ns rf pulses of greater than 500 MW. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant line (SLED-II) pulse compression system. We also present data on the processing and operation of this system, which has set high-power records in coherent and phase controlled pulsed rf.
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TL;DR: In this article, a system for detecting a fault in a first wire of a power grid that affects a transmission or reception of electromagnetic waves that transport data and that propagate along a surface of the first wire is described.
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References
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TL;DR: In this article, a theory describing the behavior of two coupled waves is presented, and it is shown that this theory applies to coupled transmission lines, and applications include highly efficient pure-mode transducers in multi-mode systems, and frequency-selective filters.
Abstract: Some theory describing the behavior of two coupled waves is presented, and it is shown that this theory applies to coupled transmission lines. A loose-coupling theory, applicable when very little power is transferred between the coupled waves, shows how to taper the coupling distribution to minimize the length of the coupling region. A tight-coupling theory, applicable when the coupling is uniform along the direction of wave propagation, shows that a periodic exchange of energy between coupled waves takes place provided that the attenuation and phase constants (α 1 and β respectively) are both equal, or provided that the phase constants are equal and the difference between the attenuation constants (α 1 — α 2 ) is small compared to the coefficient of coupling c. Either (α 1 — α 2 )/c or (β 1 — β 2 )/c being large compared to unity is sufficient to prevent appreciable energy exchange between the coupled waves. Experimental work has confirmed the theory. Applications include highly efficient pure-mode transducers in multi-mode systems, and frequency-selective filters.
442 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
TL;DR: In this paper, a four-way divider/combiner in rectangular waveguide is proposed, which is completely two-dimensional in the h-plane, with eight-fold mirror symmetry, and is based on a recent four-port hybrid design.
Abstract: We present a novel four-way divider/combiner in rectangular waveguide. The design is completely two-dimensional (2-D) in the h-plane, with eight-fold mirror symmetry, and is based on a recent four-port hybrid design. In combining mode, it can function as a phased array with four inputs and four outputs. The planar nature of this design provides advantages, such as the freedom to increase the waveguide height beyond the over-moding limit in order to reduce field strengths. Along with its open geometry, this makes it ideal for high-power applications where RF breakdown is a concern. Design criteria, field-solver simulation results, and prototype measurements are presented.
37 citations
Posted Content•
TL;DR: In this article, a four-way divider/combiner in rectangular waveguide is presented, which is completely two-dimensional in the h-plane, with eight-fold mirror symmetry, and is based on a recent four-port hybrid design.
Abstract: In this letter, we present a novel four-way divider/combiner in rectangular waveguide. The design is completely two-dimensional in the h-plane, with eight-fold mirror symmetry, and is based on a recent four-port hybrid design [6]. In combining mode, it can function as a phased array with four inputs and four outputs. The planar nature of this design provides advantages, such as the freedom to increase the waveguide height beyond the over-moding limit in order to reduce field strengths. Along with its open geometry, this makes it ideal for high-power applications where rf break down is a concern. Design criteria, field-solver simulation results, and prototype measurements are presented.
32 citations
TL;DR: In this article, the authors present theory and experimental data for a resonant-delay-line pulse-compression system, which uses evacuated room-temperature copper delay lines as a means of storing energy.
Abstract: In this paper, we present theory and experimental data for a resonant-delay-line pulse-compression system. The system is fed by two high-power klystrons at X-band. The peak output power is four times the input power. The system produces flat-top output pulses. It uses evacuated room-temperature copper delay lines as a means of storing energy. These lines achieved a quality factor greater than 4.3/spl times/10/sup 5/, with total losses due to external components measured at 4%. We compare theory with experimental results. The system produced 150-ns pulses at power levels around 470 MW.
26 citations