The Indus Booster Synchrotron RF System employs conventional high power RF amplifier based on Tetrode tube BEL 4000 CX. This tube was indigenously manufactured by M/s BEL for TV transmitters. Presently, this Tetrode tube is no more in production range and hence not available. The Booster RF cavity needs about 800 W of RF power to develop 22 kV gap voltages. Hence the development of 1 kW power amplifier based on solid state technology was taken up, which will also improve the reliability, maintainability and availability of the system.

The basic building block of high power Solid state amplifier is MRF141G based 300 watts high Power amplifier module. Four such modules are combined to get the required 1 kW of RF power. In this scheme, the signal from source at low power of 4 dBm is amplified by different stages of amplifier modules delivering final power of 1kW. This complete system includes different stage power amplifier modules, low power lumped power combiner, harmonic filter at 31.613 MHz with 33dB second harmonic attenuation and high power cable type Wilkinson power combiner. The overall gain of the amplifier is 55 dB gain and wall plug efficiency of 48%. The RF amplifier is designed to operate in ramp mode with dynamic range of 20 dB. The RF amplifier modules and combiners are water cooled to have efficient cooling and hence higher output power. This will increase the life of the amplifier by reducing failure rate of the MOSFET devices also efficiency and linearity of the amplifier is improved. To achieve high combining efficiency the gain characteristics of individual modules were matched by tuning and bias control adjustment

High Power RF Amplifier Test set-up Specifications Frequency: 31.613 MHz Gain: 55 dB Output RF power: 1kW (CW)
	Gain Characteristics