There are a variety of microwave sources capable of producing high power at the required frequencies useful for particle accelerators. Klystrons can produce power well over 100 kW, but they are very large and expensive. Inductive Output Tubes (IOTs) are relatively inexpensive but are not readily available at higher frequencies and power levels.
Magnetrons at higher frequencies with CW powers exceeding 100 kW are used for many industrial applications, and their cost is roughly $0.30 per Watt. Complete magnetron transmitters for industrial heating cost approximately $1-$3 per Watt at 915 MHz. This can be compared with greater than $5 per Watt for klystrons. The efficiency of high power magnetrons, on the other hand, is typically over 70%, and 100 kW, 915 MHz magnetrons are available with efficiencies approaching 84%. These characteristics are very attractive for accelerator applications. However, magnetrons don’t normally allow very precise control of the amplitude and the phase of the signal. Fermilab’s technique utilizes a modified Bessel function for the magnetron’s phase modulation scheme, which allows for a high degree of control over the signal’s amplitude.
Fermilab’s invention is a magnetron-based RF system capable of fast slew rates and precise control of the power and phase while dramatically reducing the cost per watt of continuous-wave RF power.
Applications and Industries
- Homeland Security
- Medical Devices
Category: Accelerator Technologies
Tags and keywords: Wideband, RF, Radio Frequency, Accelerator, Phase Modulation, Amplitude Modulation, Frequency Modulation, Hardware and accelerator control systems, Superconducting cavities
Patent Status: Patent pending
Aaron G Sauers, CLP
Fermilab, MS 312 – PO Box 500
Batavia, IL 60510