BEAM POSITION MONITOR SYSTEM OF THE ESS LINAC

The pulsed ESS Linac will include about 100 BPMs, mostly with a European XFEL style button design, 6 BPMs with a special design for the Medium Energy Beam Transport, as well as 8 compact-size BPMs foreseen for the Drift Tubes. The required accuracy and resolution of the position measurement are 100 μm (rms) and 20 μm (rms) respectively with the 50 mA 2.86 ms nominal pulse. In addition to the position measurement, the BPM system needs to measure the beam phase in the nominal pulse as well as several diagnostics pulse modes with a minimum duration and intensity of 5 μs and 5 mA respectively. After a study of the possible electronics platforms, MTCA.4 is now considered as the main prototyping platform for the high performance subsystems at ESS. It is foreseen to prototype a Rear Transition Module for IQ-based RF signal measurements intended for both the BPM and LLRF systems. The requirements and specifications of the BPM system are presented and the plan for the continuation of the project is described in this paper.