Precision current sensing and monitoring for the inflector beam of K-500 superconducting cyclotron at VECC Kolkata

The spiral Inflector of the K-500 Superconducting Cyclotron at VECC Kolkata consists of two electrodes system for bending of ions from the axial to median plane of the cyclotron. These two electrodes float potential of + 10 kV and -10kV maximum to give required electric field for proper beam bending. It is required to monitor and track the beam falling on the inflector plate from the control room while tuning the beam. Hence a precision current sensing mechanism in high side has been developed in PSI, VECC and commissioned. In this the following components have been used. (1) Precision high voltage, 50 ppm stable resistive shunt, (2) Precision, Low drift Operational Amplifier, (3) Precision V-F converter, (4) 25 KV High Frequency lsolation Transformer and (5) LabJack module for PC interface. The system is in operation. This paper describes the operation of the circuit ant the test report. (author)