A High-Efficiency L-band Solid-State Power Source for Novel Ultra-High Power Industrial Accelerators

The emerging applications of industrial irradiation, such as food irradiation or wastewater treatment, require highly efficient and inexpensive sources of MeV-level radiation. One of the promising solutions is stand-alone superconducting RF (SRF) linear accelerator that is currently being developed in Fermilab and other facilities. Such accelerator can potentially generate 1 MW beams with a >40% wall-plug power efficiency. To reach such high efficiency numbers, the RF power sources must have the DC-to-RF conversion efficiencies of >70%, while having the costs of ~$1/W. Out of all available technologies, only solid-state amplifiers (SSA) could possibly achieve this merit. In response to this problem, RadiaBeam Technologies plans to develop a 20 kW CW 650 MHz SSA capable of achieving wall-plug efficiency over 70% by enabling class-E operation. This work will leverage our experience from the successful building of a 6 kW CW 1.5 GHz solid-state generator based on GaN technology. The modularity of the proposed system enables easy scalability for the 80 kW CW output level currently required for the IARC accelerator prototype, and also for higher power levels up to several hundreds of kW. In Phase I, we will design, fabricate and test a single GaN-based power amplifier module demonstrating the required efficiency in Class-E delivering 1 kW CW power at 650 MHz. We will also test the other critical components such as biasing/switching networks, PIN-diodes (proposed to enable wide output power adjustment while preserving high efficiency), cooling system and power combiner. Finally, we will perform simulations of the proposed RF switches and prepare a modular layout of the full-power system to be built and tested Phase II. This development will create a significant and sustainable competitive advantage over its competitors within the industry through the introduction of high-power CW SSAs with > 70% wall-plug efficiency and improved modularity and reliability. In total, there are about 20 laboratories and light source facilities around the world that would serve as first customers or potential early adopters of the developed high efficiency solid state power amplifier. Besides the industrial applications, efficient SSA are required by many high-energy accelerators including PIP-II, EIC, and FRIB, which have active upgrade programs. We estimate the initial customer base (accelerator facilities and the radiation industry) will require at least 1,000 SSAs over the next ten years.