A Cyclotron Power-Amplifier RF System Using a 4CW50,000/8350 Tetrode

The radio frequency system of the Universit f Colorado 52" cyclotron has been described at earlier stages in its evolution. The purpos of the present report is to describe a major change in the power amplifier and other changes in the control circuits, and to report operating experienc with the system. Table 1 lists some of the parameters of the system. The change in the power amplifier resulted in an appreciable simplification. Excluding the dee resonant circuit, there is now only one circuit in the rf system requiring remote tuning. The dee voltage control circuit incorporates current limiting protection for the power amplifier tubes to prevent damage to the system by inexperienced operators. The System is particularly easy to operate. After the operator has set the system up on the operating frequency and the dee voltag ontrol is set to the desired value, the dee voltage is turned on and off by means of two push buttons, and requires no other attention. Change in frequency require from one to ten minutes, depending on the distance that the short must be moved.