Low-Noise Wide-Band Amplifier System for Stochastic Beam Cooling Experiments

A new low-noise wide-band power amplifier system has been developed for stochastic beam cooling experiments. The system incorporates a low-noise preamplifier with a noise figure of 1.9 dB over a bandwidth range of 20 to 300 MHz, wide-band driver and buffer stages, a frequency characteristics shaping network, a remotely controlled wide-band attenuator with 0.1 dB resolution, a remotely controlled high resolution adjustable delay line, and a wide-band solid-state output power amplifier. The amplifier system has a maximum voltage gain of 140 dB over a bandwidth from 1.5 to 310 MHz, a signal group delay of 55.5 ns, and a c. w. output power level of 75 W. Particular attention was paid to minimizing the signal propagation time delay of the amplifier system, the propagation time delay change as a function of the system gain, and harmonic and intermodulation distortions. Using a new wide-band electron bombarded semiconductor output amplifier, the system will have a bandwidth from 30 to 400 MHz, a signal group delay of 37 ns and an output power of 100 W.