Papers presented at IPAC 2016
The new Ion Source Test Facility (ISTF) designed by D-Pace Inc. and installed at Buckley Systems Ltd in Auckland, New Zealand has already been used to perform experiments that form the basis for two scientific papers presented at the IPAC 2016 conference. The following is a summary of A PID Control Algorithm for Filament Powered Volume-Cusp Ion Sources, presented by S. Melanson:
The plasma inside the TRIUMF licensed, D-Pace designed, ion source is generated by passing a current through a tantalum filament assembly. Since the generation of plasma with a filament is highly nonlinear, a proportional-integralderivative (PID) control algorithm was implemented to precisely control the filament current in response to measured changes in the discharge current. Once filament power supply current passes the threshold of Townsend discharge, the filament current needs to be reduced to keep the arc current and ion beam constant.
To evaluate the algorithm on the ISTF, the arc current was set at 24.6 A, the arc voltage was fixed at 130 V and the H2 gas flow set at 15 sccm. Over 60 minutes of operation, we obtained a root mean square error in the arc current of 0.058 A and 0.025 mA for a beam current of 10.16mA on the Faraday cup. The maximum peakto-peak variation was ±0.76% for the arc current and ±0.45% for the beam current.
The complete paper including actual test results is available on request from D-Pace Inc. or Buckley Systems Ltd.
This piece was reprinted by D-Pace, Inc. from the Buckley Systems Summer 2016 technical bulletin with permission from Buckley Systems Ltd. It may not be reproduced in any form without permission or license from the source.