Solid State Power Amplifier – development of the next 400 kW power station for ESS

Coordinating university or institute

Uppsala University,



Project description

To ensure a continuous improvement of the operations at ESS in the long term and, to benefit from cutting edge technology, the FREIA laboratory at Uppsala University has undertaken the development of a Radio Frequency (RF) Solid State Power Amplifier (SSPA) station of 400 kW at 352 MHz. SSPA offers many advantages compared to vacuum tube technology, such as: (i) longer lifetime and longer mean time between failures (MTBF) considering more than 10 years operation 24/7, (ii) additional safety using much lower voltages i.e. 50 V v.s. 16 kV, (iii) additional redundancy in operation by combining many SSPAs, (iv) support from a mature and growing semiconductor industry while (v) vacuum tube manufacturers suffer from obsolescence and their number is continuously decreasing. The output power of SSPA modules is relatively low (i.e. 1 kW) and many SSPAs need to be combined in order to produce the peak power levels required. Power combination is key for enabling the economic viability of the system. In the same time, we develop adaptive control mechanisms to make hundreds of amplifier pulse in concert with optimal energy efficiency. ESS will operate 26 power stations, each of 400 kW peak power at 352 MHz.


2017 - ongoing


Uppsala University

  • Dragos Dancila, Associate professor, Department of physics and astronomy
  • Kristiaan Pelckmans, Associate professor, IT, Division of Systems and Control
  • Anders Rydberg, Professor, Department of physics and astronomy, FREIA
  • Alireza Kasaee, Postdoc, Department of physics and astronomy, FREIA
  • Renbin Tong, Student, Department of Electrical Engineering, Solid state electronics

Core deliverables

Solid State power amplifier modules at kilowatt level and high power combiners development up to 400 kW and up to 300:1 combination ratio. Adaptive control procedure for up to 400 amplifiers optimization. Specific design for superconductive cavity particle accelerators. System design and specifications. High speed data analysis and control using FPGA. System integration and commissioning. High power testing bench and continuous development.

Industry involvement

  • ESS, Sweden
  • ESRF, France
  • CERN, Switzerland
  • GE Healthcare – collaboration on SSPA for cyclotrons
  • Exir AB – waveguides and combiners
  • Percyroc AB – signal generators and adaptive control

Total budget

EUR 1 million
210622 Freia Sspa Illustration Webb (2)

Procurement codes

Electronics and radio frequency
Electrical Engineering and magnets
Information technology
Mechanical Engineering and raw materials

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