High energy transmission with RF generators in High-Energy Physics Research Centers

In high-energy physics research centers, RF (radio frequency) generators play a crucial role in producing the electromagnetic waves necessary for several research applications, including particle acceleration, plasma generation, and heating. These generators convert electrical energy into high-frequency RF signals, which are then used to power various systems in the research centers.

RF feed line systems are essential for efficiently transferring the RF energy produced by high-power RF generators to their intended applications. These systems consist of coaxial cables, waveguides, impedance matching networks, and other components designed to handle high-power RF transmission without significant energy loss.

SPINNER RF feed line systems are crucial components for transmission of high energy

RF generators and their supporting RF feed line systems are critical in high-energy physics research centers for powering particle accelerators, heating plasmas, and generating electromagnetic fields for various experiments. The key success factors for these components are their ability to handle high-power, high-voltage RF signals, minimize losses, and maintain impedance matching. Successful RF system operation underpins many experiments in fusion energy and particle physics research worldwide, particularly in facilities such as CERN, ITER, and SLAC. Key functions are:

  • Power Transmission: RF feed line systems transport high-power RF signals from the RF sources to the accelerating cavities. The system must minimize power losses to ensure efficient transmission.
  • Impedance Matching: Proper impedance matching between the RF source, feed line, and cavity is critical to minimize reflections and power loss, ensuring maximum energy transfer.
  • Phase Stability: In many accelerators, the phase of the RF signal is synchronized with the particle bunches. The feed line system must maintain phase stability to ensure consistent acceleration.
  • Thermal Management: High-power RF systems generate significant heat. The feed line system must be designed to manage this heat, typically through cooling systems or heat-resistant materials.
  • Mechanical Stability: The RF feed lines must maintain structural integrity under various operating conditions, including high vacuum, temperature variations, and mechanical stresses.
  • Low Loss and High Efficiency: The feed line system must minimize losses (both resistive and dielectric) to ensure that most of the RF power reaches the accelerating cavities.

Key components for high energy transmission are:

  • Rigid rectangular Waveguides and rigid coaxial lines: Metallic structures that guide RF power from the klystrons or amplifiers to the accelerating cavities. Waveguides must have low loss and be precisely engineered to maintain phase stability.
  • Coaxial Cables: Used for lower power RF transmission, coaxial cables also play a role in delivering RF signals, particularly in diagnostics and control systems.
  • Directional Couplers: Devices that allow for controlled introduction of RF power into the accelerator cavities. The coupling factor is crucial for optimizing energy transfer.
  • Phase Shifters: Devices that adjust the phase of the RF signal to synchronize with the particle bunches, crucial for maintaining stable acceleration.
  • Adapters: Devices to connect waveguides with different interfaces.
  • Loads: loads are placed to the end of the power path and thus guarantees the correct termination. This reduces disturbing reflections and ensures the maximum performance and quality of the overall system.
  • Power Combiners: Combining multiple power sources into one transmission line.

SPINNER rf components excel by delivering exceptional value at the technical success factors and crucial requirements for high energy transmission like

  • High Power Handling: our RF components can handle high power levels without significant losses or overheating.
  • Precision in Manufacturing: accurate manufacturing, especially for components like waveguides and cavities, ensure impedance matching and minimize reflection.
  • Thermal Stability: our components withstand the heat generated by high-power RF without degradation, in required with advanced materials and cooling systems.
  • Mechanical Stability: the RF feed lines are robust against physical stresses and vibrations, maintaining alignment and phase stability over long periods.
  • Low Loss: Minimizing resistive and dielectric losses in components like waveguides and coaxial cables is guaranteed for efficient power transfer.
  • Phase and Frequency Stability: we ensure that the RF signal remains stable in phase and frequency which is crucial for synchronizing with the particle bunches.
  • Reliability and Maintenance: our system is highly reliable with low maintenance requirements to ensure continuous operation of the accelerator.

These factors collectively determine the efficiency, stability, and effectiveness of the RF feed line systems in high-energy physics research centers.

We have been developing and supplying special radio frequency high energy components for a variety of high power projects since 1967:

  • In 1967 SPINNER supplied the first coaxial transmission lines for transmitter matching (with 250 kW of power at 200 MHz) for the Proton Synchotron (PS) of CERN.
  • In 1978/1979 CERN once again relies on SPINNER components, this time for its Super Proton Synchrotron. For expanding the SPS (Super Proton Synchrotron) particle accelerator, SPINNER is contracted to develop and deliver a 16 x combiner for parallel switching of 16 transmitters each (60 kW each, CW at 200 MHz), an eight-transmitter combiner (8×60 kW, CW at 800 MHz), and a coaxial switch 150-345 (for 1 MW; CW at 200 MHz).
  • In 1981 SPINNER supplies coaxial high-power lines RL100-230 (50 ohms), stub tuners, DC breakers, absorbers, and switches to the IPP (Max Planck Institute for Plasma Physics) for its experimental Tokamak ASDEX and Wendelstein fusion reactors.
  • In 1983 SPINNER supplied R32 waveguide components in high-vacuum technology for the first time for the LEP-Linac (Large Electron/Positron Collider) for CERN and installed the complete waveguide transmission systems with power splitters, pumping ports, switches, directional couplers as well as phase shifters from the 35 MW klystrons to the accelerator structures.
  • In 1985 SPINNER completes an order for the LEP Linac at CERN: For the LEP Injector Linac of the Large Electron-Positron Collider at CERN in Switzerland, SPINNER develops and supplies 3 GHz accelerator structures (with 135 cavities) and the 3 GHz reference line in 1 5/8″ for driving the klystrons.
  • In 2004, it still isn’t clear where the gigantic International Thermonuclear Experimental Reactor (ITER) will be built. Despite this, required preliminary development projects have already been running at full speed for several years. They include work at the JET (Joint European Torus) in the United Kingdom to optimize the ICRH (for Ion Cyclotron Resonance Heating) plasma heating mode that will be used. SPINNER supplies two MW transmission lines for it.
  • In 2011, MedAustron, one of Europe’s most advanced centers for ion beam therapy and research, opened in Wiener Neustadt south of Vienna, Austria relying on SPINNER RF components. In addition to treating patients in clinical trials, the center also hosts nonclinical research.