SNS Low-Level RF Control System: Design and Performance

A full digital RF field control module (FCM) has been developed for SNS LINAC. The digital hardware for all the control and DSP functionalities, including the final vector modulation as well as IF output synthesis, is implemented on a single high-density FPGA. Two of its HDL models have been written in VHDL and Verilog respectively, and both have being used to support the testing and commissioning of the LINAC to the date. The control algorithm used in the HDL produces a latency as low as 150nS. During the commissioning, the flexibility and capacity for needed precise controls that only digital design can provide has proved to be a necessity for meeting the great challenge of a high-power pulsed SCL.