RF sources for electron linacs

The Accelerator and Pulse Power Division of BARC has designed and developed indigenous high power RF electron linacs for industrial applications. These include the 10 MeV Industrial RF Linac at Electron Beam Centre, Navi Mumbai, the 9 MeV RF linac for demonstration of cargo scanning and a dual 6/3 MeV compact linac for mobile cargo-scanning system. In addition, a 30 MeV linac for neutron production is in the development stage. A 100 MeV, 100 kW linac for ADS studies is also being planned. These linacs operate at 2856 MHz in the pulsed mode with variable duty cycles. RF power required for the linacs is derived from klystrons or magnetrons. Pulsed high voltage required to energize the klystron/magnetron is generated with the help of pulse modulators. The RF power generated by the klystron is fed to the linac through the WR284-based waveguide plumbline comprising of the directional couplers, circulator with matched water loads, E and H-bends and ceramic window. This paper discusses the salient features of the RF power sources used in the various linac systems, including the 6 MW source for 10 MeV linac based on multi-beam klystron (Toriy-157A), 7.5 MW source for 30 MeV linac based on single-beam klystron (Thales-2163) and 3 MW magnetron-based source for compact linac. A description of the indigenous design and development of components of the RF source is also presented. (author)