• T. Lefèvre, S. Bart Pedersen, A. Boccardi, E. Bravin, A. Goldblatt, A. Jeff, F. Roncarolo
  CERN, Geneva
• A.S. Fisher
  SLAC, Menlo Park, California

The LHC beam dump system relies on extraction kickers that need 3 microseconds to rise up to their nominal field. As a consequence, particles crossing the kickers during this rise time will not be dumped properly. The proton population during this time should remain below quench and damage limits at all times. A specific monitor has been designed to measure the particle population in this gap. It is based on the detection of Synchrotron radiation using a gated photomultiplier. Since the quench and damage limits change with the beam energy, the acceptable population in the abort gap and the settings of the monitor must be adapted accordingly. This paper presents the design of the monitor, the calibration procedure and the detector performance with beam.