Single photon detector tests for the LHC synchrotron light diagnostics

A synchrotron light detector using a Single-Photon Avalanche Detector (SPAD) is planned for the LHC longitudinal diagnostics monitor, an application which requires high count rate, low noise and good time resolution. SPAD detectors have been developed at Milan Polytechnic with active quenching circuits. Initial tests of these detectors and currently available commercial timeto- digital data acquisition equipment were made at the ESRF. We present the results of those tests, an estimation of the performance that can be expected for the LHC case and an analysis of the difficulties, constraints and potential of this type of detector.