Digital RF control for spallation neutron source accumulator ring

The proposed upgrade plan for the rf control of the Spallation Neutron Source (SNS) accumulator ring requires that the new digital field control module (FCM) have the capability of adaptive feed forward (AFF) compensation for the heavy beam loading in the cavities. The feed forward compensation capability should support both the conventional software driven AFF algorithm and a new beam current driven AFF algorithm. A user-friendly Epics GUI for all the FCM functionalities is also a part of the requirement. The first prototype for test has been built. It is a narrowband system based on the conventional I/Q sampling scheme. Both the hardware and software are currently under test in the lab, and the field test in a near future has been planned.