Measurement of Beam Loss at the Australian Synchrotron

The unprecedented requirements that new machines are setting on their diagnostic systems is leading to the development of new generation of devices with large dynamic range, sensitivity and time resolution. Beam loss detection is particularly challenging due to the large extension of new facilities that need to be covered with localized detector. Candidates to mitigate this problem consist of systems in which the sensitive part of the radiation detectors can be extended over long distance of beam lines. In this document we study the feasibility of a BLM system based on optical fiber as an active detector for an electron storage ring. The Australian Synchrotron (AS) comprises a 216m ring that stores electrons up to 3GeV. The Accelerator has recently claimed the world record ultra low transverse emittance (below pm rad) and its surroundings are rich in synchrotron radiation. Therefore, the AS provides beam conditions very similar to those expected in the CLIC/ILC damping rings. A qualitative benchmark of beam losses in a damping ring-like environment is presented here. A wide range of beam loss rates can be achieved by modifying three beam parameters strongly correlated to the beam lifetime: bunch charge (with a variation range between 1 uA and 10mA), horizontal/vertical coupling and of dynamic aperture. The controlled beam losses are observed by means of the Cherenkov light produced in a 365 μ m core Silica fiber. The output light is coupled to different type of photo sensors namely: Multi Pixel Photon Counters (MPPCs), standard PhotoMulTiplier (PMT) tubes, Avalanche PhotoDiodes (APD) and PIN diodes. A detailed comparison of the sensitivities and time resolution obtained with the different read-outs are discussed in this contribution.