CERN, Geneva, Switzerland
IOFFE, St. Petersburg, Russia
CIVIDEC Instrumentation, Wien, Austria
The Beam Loss Monitoring system of the Large Hadron Collider close to the interaction points contains mostly gas ionization chambers working at room temperature, located far from the superconducting coils of the magnets. The system records particles lost from circulating proton beams, but is also sensitive to particles coming from the experimental collisions, which do not contribute significantly to the heat deposition in the superconducting coils. In the future, with beams of higher brightness resulting in higher luminosity, distinguishing between these interaction products and dangerous quench-provoking beam losses from the circulating beams will be difficult. It is proposed to optimise by locating beam loss monitors inside the cold mass of the magnets, housing the superconducting coils, in a superfluid helium environment, at 1.9 K. This contribution will present results of radiation hardness test of p+-n-n+ silicon detectors which, together with single crystal Chemical Vapour Deposition diamond, are the main candidates for these future cryogenic beam loss monitors.
CERN, Geneva, Switzerland
Royal Holloway, University of London, Surrey, United Kingdom
CIVIDEC Instrumentation, Wien, Austria
A laser-based profile monitor has been designed for commissioning of CERN's LINAC4 accelerator at 50 MeV and 100 MeV, as part of the development of a non-destructive profile and emittance monitor foreseen for the final 160 MeV beam. The system is based on a low power laser which is scanned through the H− beam. Electrons, which are photo-detached from the ions by the laser, are deflected by a steerer magnet and measured by a diamond detector. The custom designed diamond detector is tailored to minimize the disturbance due to the electromagnetic field of the passing main beam. The laser source will be installed in the LINAC4 Klystron gallery located 75 m away from the profile station and an optical fiber will transport the laser to the tunnel. The laser propagation for different pulse length and peak power values was characterized with laboratory tests with such a long fiber. In this paper we describe the overall design, focusing on key elements such as the fiber-based laser transport and the electron detection with the diamond detector.
