A high power water cooled resistor for the high voltage power supply in the TRIUMF RF system

The TRIUMF RF system high voltage power supply requires 0.5 ohm current limiting resistors to protect amplifier components during transients and crowbar operations. The crowbar typically causes a 16000 amp transient pulse, followed by a 4000 amp current for 55 ms until the circuit breaker opens. The resulting stresses produced catastrophic failure of the original design within 100 crowbar cycles. A new resistor design has been developed to improve heat transfer characteristics and reduce current densities. Design changes were evaluated during extensive testing of a full scale model. The test results are reported with the resulting design described in detail