New Electron Cloud Detectors for the CERN Proton Synchrotron

Electron cloud (EC) has already been observed during normal operation of the PS using classical shielded button pick-up detectors in drift sections. In the context of the LHC Injector Upgrade (LIU project), similar measurements are also needed for the combined function magnets of the machine, where the access to the vacuum chamber is strongly limited by the presence of the yoke. Two new electron cloud detectors have been studied, developed, and installed during the Long Shutdown (LS1) in one of such magnets. The first is based on current measurement by using a shielded button-type pick-up with a special geometry to reach the bottom surface of the vacuum pipe embedded in the magnet. The second one relies on a newly developed measurement method based on detection of the photons, which are emitted by cathodoluminescence from the electron cloud impinging on the vacuum chamber walls. Part of the emitted photons is collected through a quartz window by a Micro-Channel Plate Photomultiplier Tube (MCP-PMT). First results obtained during machine development runs show the feasibility of the photon detection scheme. The results are discussed and compared with pick-up measurements.