Development and performance of electrostatic deflector insulators for the Chalk River superconducting cyclotron

The electrostatic deflector in the Chalk River superconducting cyclotron has a dee shape, and has a single fixed deflector electrode suspended from two insulators located above the midplane. One of them contains a high-voltage cable and a series water resistor to limit energy available to a spark and to isolate the high-voltage cable and DC power supply from RF pickup. The other insulator is a conventional cylindrical post. The insulators have been changed from the original design to make them less prone to thermal damage from RF heating. Details are given of the water system electrical performance and of insulator modifications and performance.<>