The Linac4 vacuum control system

Linac4 is 160 MeV H⁻ linear accelerator replacing Linac2 as the first injector to the CERN accelerator complex, which culminates with the Large Hadron Collider. This new Linac will increase the beam brightness by a factor of two. The vacuum installation consists of 235 remotely controlled pumps, valves and gauges. These instruments are either controlled individually or driven by pumping stations and gas injection processes. Valves and pumps are interlocked according to gauge pressure levels and pump statuses. The vacuum control system communicates with the beam interlock system, the ion source electronics and the Radio Frequency control system, through cabled digital and analog signals. The vacuum control system is based on commercial Programmable Logical Controllers (Siemens PLCs) and a Supervisory Control And Data Acquisition application (Siemens SCADA: WINCC OA). This paper describes the control architecture and process, and reports on the control requirements and the implemented solutions.