Keishi Sakamoto, Executive Officer of Kyoto Fusioneering, receives the John R. Pierce Award from the Institute of Electrical and Electronics Engineers (IEEE), USA.

HOME > NEWS > Keishi Sakamoto, Executive Officer of Kyoto Fusioneering, receives the John R. Pierce Award from the Institute of Electrical and Electronics Engineers (IEEE), USA.

Kyoto Fusioneering(KF)is pleased to announce that Prof. Keishi Sakamoto, Executive Officer of KF, has received the John R. Pierce Award, presented by the Institute of Electrical and Electronics Engineers of USA, for his outstanding contributions and leadership in the field of vacuum electronics

Prof. Sakamoto has been involved in the development of high-power gyrotrons (*), which are plasma heating devices, at the Japan Atomic Energy Research Institute (JAERI/JAEA) and the National Institutes for Quantum Science and Technology (QST) since the 1980s, and has led the industry as a pioneer in gyrotron development to date. He significantly improved the performance of the gyrotron through trial and error and design changes from the time when other plasma heating methods, such as neutral beam injectors, were considered superior. His innovations and discoveries contributed to the growing recognition of gyrotrons as a viable heating method. Since joining KF in 2021, in addition to scientific investigation at the research institute, he has played a major role in shaping the gyrotron industry in the private sector.

This award acknowledges Prof. Sakamoto and his team’s continued progress in developing proprietary gyrotron technology  over the past few decades. The recognition of his  intellectual achievements signifies  the importance of his contribution to develop low carbon commercial fusion technology.

Prof. Sakamoto’s Comment
I am humbled to receive the IEEE John R. Pierce Award. This award is a global recognition of the research and development work that we have been carrying out together with our colleagues for many years at the Japan Atomic Energy Research Institute (JAERI/JAEA) and the National Institutes for Quantum Science and Technology (QST). At the same time, this R&D result has been made possible through the cooperation of industry, including Toshiba, Canon Electron Tube Devices, JASTEC and Kyocera. Through the diffusion of gyrotron technology currently promoted by Kyoto Fusioneering, we will continue to strive for the development of technology initiated in Japan.

IEEE・John. R Pierce Award

The Institute of Electrical and Electronics Engineers, founded in 1963 through the merger of the American Institute of Electrical Engineers and the Institute of Radio Engineers, is the world’s largest academic research organisation, with 410,000 members in 160 countries.

The John R. Pierce Award is presented annually by the IEEE Electron Device Society to the person who has made the greatest contribution to the industry.

Prof. Sakamoto’s Biography

After graduating with a Master’s degree in nuclear engineering from Kyushu University, he led the design and development of a gyrotron for ITER at QST for many years. He obtained his PhD from Kyushu University in 1993. He has served as a professor at the Institute of Fusion Science, University of Tsukuba and University of Fukui, and as a director of the Plasma and Fusion Society of Japan. He joined Kyoto Fusioneering in April 2021 as an Executive Officer. 

*About Gyrotron
A gyrotron is a large vacuum tube capable of continuous 1 MW-class output power with high-power millimeter waves, which consists of the gyrotron body, a superconducting solenoid coil (SCM), and a DC power supply.

The cavity resonator inside the gyrotron oscillates 1 MW-class millimeter waves, which are reflected by an internal mirror and exit to the outside through a vacuum-sealed window to be injected into the fusion reactor via a waveguide.

Gyrotron applications include plasma heating to over 100 million degrees Celsius, which is necessary for fusion reactions, and for stable plasma control. Research is also being conducted into other industrial applications, such as deep drilling for geothermal power generation using electromagnetic waves emitted from gyrotrons, and materials research for medical purposes.

In Japan, the JAERI and other organisations began developing this technology in the 1980s, as part of fusion plasma research, but initially it was not regarded as a viable plasma heater due to its low power efficiency (20-30%) and insufficient power output (<0.2 MW). Subsequent improvements were made, including a collector inside the gyrotron to absorb some of the electricity consumed, and in 1994 the gyrotron achieved an efficiency of 50% and an output of 0.5 MW x 3 s. Furthermore, diamond, with its extremely high thermal conductivity, began to be used for vacuum windows, the exit point for millimetre waves, enabling higher power output for longer periods of time.

As a result of these developments, in 1999, four gyrotrons were delivered to the large tokamak reactor JT-60U, which was being developed by JAERI. Since the 2000s, development and production for ITER has also progressed, with all eight gyrotrons ordered by QST being delivered to ITER in 2021.

Please check KF’s world leading gyrotron here.


  • K. Sakamoto et al. “Major Improvement of Gyrotron Efficiency with Beam Energy Recovery.”  Physical Reciew Letters, vol. 73, no. 26, 1994, pp. 3532-3535. 
  • K. Sakamoto et al.  “High power 170 GHz gyrotron with synthetic diamond window .”  Reviews of Scientific Instruments, vol. 70, no. 1, 1999, pp. 208-212. 
  • K. Sakamoto et al. “Achievement of robust high-efficiency 1MW oscillation in the hard-self-excitation region by a 170 GHz continuous-wave gyrotron .”  Nature Physics, vol 3, 2007, pp.411-414.  
  • K. Sakamoto et al. “Progress of high power 170 GHz gyrotron in JAEA.”  Nucl. Fusion, vol 49, no. 9, 2007, pp.095019_1-095019_6.  
  • K. Sakamoto et al. “Development of 170 and 110 GHz gyrotrons for fusion devices”  Nucl. Fusion, vol 43, no. 7, 2003, pp.729-737.  

About Kyoto Fusioneering Ltd.
Kyoto Fusioneering is a privately funded technology start-up founded in 2019, with its headquarters in Kyoto, Japan. The company is focused on developing advanced technologies for commercial fusion reactors, including gyrotron systems, tritium fuel cycle technologies, and breeding blankets for tritium production and power generation. Kyoto Fusioneering is developing innovative solutions that are simultaneously high-performance and commercially viable. Supporting both public and private fusion developers around the world, the company is accelerating the realization of fusion as the ultimate energy source for humankind.

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