The Linac4 Source Autopilot

The Linac4 source is a 2MHz, RF driven, H⁻ ion source, using caesium injection to enhance H⁻ production and lower the electron to H⁻ ratio. The source operates with 800µs long pulses at 1.2 second intervals. The stability of the beam intensity from the source requires adjustment of parameters like RF power used for plasma heating. The Linac4 Source Autopilot improves the stability and uptime of the source, by using high-level automation to monitor and control Device parameters of the source, in a time range of minutes to days. This paper describes the Autopilot framework, which incorporates standard CERN accelerator Controls infrastructure, and enables users to add domain specific code for their needs. User code typically runs continuously, adapting Device settings based on acquisitions. Typical use cases are slow feedback systems and procedure automation (e.g. resetting equipment). The novelty of the Autopilot is the successful integration of the Controls software based predominantly on Java technologies, with domain specific user code written in Python. This allows users to leverage a robust Controls infrastructure, with minimal effort, using the agility of the Python ecosystem.