6 MW S-band Klystron

CSIR-CEERI has been engaged in the design and development of a 6 MW peak, 24 kW average power S-band Klystron with financial support from Bhabha Atomic Research Centre (BARC), Mumbai.

The Klystron would be used as high power RF source for 10 MeV Industrial Linear Accelerator, which is under development at BARC. One of the primary uses of the accelerator would be scanning of thick steel-walled cargo containers at various ports, using strong X-rays produced by accelerated electrons hitting a suitable metal target. The accelerator is also expected to cater a variety of other applications such as food irradiation, cable hardening, rubber vulcanization, and for creating exotic colours in precious gemstones through electron implantation.

The klystron is a multi-cavity klystron with an RF coaxial input and a waveguide output through a pill-box-type window. The RF section and collector are cooled using forced water circulation. An electromagnet provides the focussing magnetic field with water-cooled hollow copper tubing. During the operation, the electron gun remains immersed in oil, which improves voltage breakdown strength and provides a cooled environment. The prototype of the klystron is shown in the Fig. 1.

Fig. 1: 6 MW S-band Klystron

Three prototypes of klystron have been developed so far. After successful testing with BARC scientists at CSIR-CEERI, one klystron has been delivered to BARC in December, 2015. The testing of the klystron as standalone system using pulse power supply is under way at BARC, Mumbai.


  • Beam voltage: 135 kV
  • Beam current: 116 A
  • Filament voltage: 10 V
  • Filament current: 30 A
  • Operating frequency: 2856± 4 MHz
  • Output power: 6 MW (Peak)
  • Pulse width 10 μS
  • PRF: 400 Hz
  • RF input: Type N
  • RF output: Waveguide WR284
  • Focussing: Electromagnet
  • Cooling: Forced water