Testing of a 10 MW, 1.3 GHz annular beam klystron is reported.

Calabazas Creek Research is developing several, high power, periodic permanent magnet (PPM) focused klystrons. PPM focusing offers reduced power consumption and low weight. We report on the design and testing of an S-band, pulsed klystron capable of providing 5 MW power for advanced medical and industrial accelerators, and on the design of the gun and magnetic structure for a PPM-focused, multiple beam klystron with a beam power of 320 kW CW.

A C-Band, multiple beam klystron was designed, fabricated, prepared for high voltage testing. The klystron employs controlled porosity reservoir cathodes operating at 30 A/cm(2) to generate 18 beams. The RF circuit consists of eight buncher cavities and an extended interaction output cavity. The challenge was achieving the required 6.6% bandwidth. The gun includes a grid for fast pulse operation. The klystron design and available test results will be reported.

This program developed a 10 MW, pulsed, Annular Beam Klystron (ABK) for accelerator applications. This is an alternative RF source to multiple beam klystrons MBKs), which are more complex and considerably more expensive. The ABK uses a single, annular cathode and a single beam tunnel with fundamental mode cavities. The operating specifications (voltage, efficiency, power, bndwidth, duty, etc.) are the same as for comparable MBKs.

Calabazas Creek Research, Inc. is developing a 10 kW CW, high efficiency, S-band, Periodic Permanent Magnet (PPM) focused klystron capable of driving accelerator cavities. The presentation will describe the design, computational analysis, and measured results. Measurements will be compared to simulation results from the large signal codes KLSC and Tesla.

Toward the goal of making Beam Optics Analyzer (BOA) a multiphysics modeling and simulation tool for electron beam devices, we will present the new nonlinear heat transfer capability in BOA. We will discuss the finite element formulation and numerical results with regard to temperature dependent materials and radiative heat transfer coupled with power densities generated from electron beams.

The design of a 10 MW, 1.3-GHz annular beam klystron for accelerator applications has been analyzed in detail and optimized. Concerns about the diocotron instability were addressed by simulations, which showed the growth to be negligible. The calculated efficiency is 66%.

Calabazas Creek Research is developing several high power S-band periodic permanent magnet (PPM) focused klystrons. We report on the design of a 5.5 MW pulsed klystron and a 75 MW pulsed klystron, both for providing high peak power for advanced accelerators. The efficiency requirement of both klystrons is determined by system requirements. We will present results from extensive simulations using out in-house large signal klystron code (KLSC) and the large signal code TESLA. We will also describe our unique PPM structures which permits direct access to frequency tuning and liquid cooling of the individual cavities.

Fabrication and testing of a 10 MW, 1.3 GHz annular beam klystron is reported.

Calabazas Creek Research, Inc. is developing a 10 kW CW, high efficiency, S-band, Periodic Permanent Magnet (PPM) focused klystron capable of driving accelerator cavities. The presentation will describe the design, computational analysis, and measured results. Measurements will be compared to simulation results from the large signal codes KLSC and Tesla.

Calabazas Creek Research, Inc. is developing a 50 MW Periodic Permanent Magnet (PPM) Focused High Efficiency klystron capable of driving advanced superconducting linacs. The development addresses the high RF power needs for the LANL MaRIE proton linear accelerator. We will present tabulated and graphical data showing in detail the performance of this pulsed klystron. We will compare results from our in-house klystron large signal code, KLSC and our leased large signal code, TESLA for a 7 cavity circuit. We will also present results for a single output cavity and for a multiple cavity extended interaction circuit (EIC).

Several new RF sources are being developed for accelerator and collider applications. Assembly is nearing completion of a multiple beam inductive output tube at 352 MHz. An annular beam klystron is being developed to produce 10 MW pulses at 1.3 GHz. The annular beam approach provides significant cost reduction over similar multiple beam devices. Fabrication is underway on a 10 kW, periodic permanent magnet klystron at 2.815 GHz. Permanent magnets eliminate the solenoid and associated power supplies and cooling requirements to reduce operational cost. Investigations are beginning on a novel approach for driving accelerator cavities using pulse shaping to increase coupling efficiency and dramatically reduce RF power requirements.

The design of a 10 MW, 1.3 GHz Annular Beam Klystron for ILC has been analyzed in detail and optimized. Concerns about the diocotron instability were addressed by MAGIC simulations, which showed the growth to be negligible. Design improvements reduced the number of cavities to six and increased the efficiency to 66%. The magnetic field was reduced by 25%, decreasing the power required for the solenoid to less than 4% of the average power of the tube.

Calabazas Creek Research, Inc. (CCR) performed initial development of a compact and reliable 35 MW, multiple beam klystron (MBK) at 200 MHz with a pulse length of 0.125 ms and a 30 Hz repetition rate. The device was targeted for acceleration and ionization cooling of a muon collider, but there are several other potential applications in this frequency range. The klystron uses multiple beams propagating in individual beam tunnels to reduce space charge and allow reduction in the accelerating voltage. This allows a significant reduction in length over a single beam source. More importantly this allows more efficient and less expensive power supplies. At 200 MHz, the interaction circuit for a single beam klystron would be more than six meters long to obtain 50% efficiency and 50 dB gain. This would require a beam voltage of approximately 400 kV and current of 251 A for a microperveance of 1.0. For an eight beam MBK with the same beam perveance, a three meter long interaction circuit achieves the same power and gain. Each beam operates at 142 kV and 70A. The Phase I demonstrated that this device could be fabricated with funding available in a Phase II program and could achieve the program specifications.

This paper describes a 100 kW CW, S-Band klystron that is being developed for use in high energy accelerator applications. Focusing for the beam is provided by a PPM structure. The principal components of the device, including the RF structure, electron gun, and magnetics are described.