• B. Goddard, R.W. Assmann, W. Bartmann, C. Bracco, E. Carlier, V. Kain, M. Meddahi, A. Nordt, S. Redaelli, J.A. Uythoven, J. Wenninger
  CERN, Geneva

The LHC transfer lines, injection and beam dump systems are equipped with a series of active and passive protection systems. These are designed to prevent as many failures as possible, for example through surveillance and interlocking, or to absorb any beam which is mis-kicked or mis-steered on passive absorbers. The commissioning, validation tests and performance of the different systems are described, and the implications for the protection of the LHC against different failures during beam transfer are discussed.

• C. Bracco, R.W. Assmann, W. Bartmann, C. Boucly, R. Bruce, E. Carlier, B. Dehning, B. Goddard, E.B. Holzer, M. Meddahi, A. Nordt, S. Redaelli, A. Rossi, M. Sapinski, J.A. Uythoven, D. Wollmann
  CERN, Geneva

A single-sided mobile diluter (TCDQ) and a horizontal secondary collimator(TCSG) are installed in the extraction region of the LHC to protect the downstream elements from damage in case of asynchronous beam dump. These collimators have to be precisely setup to shield the arc aperture at 450 GeV, the triplet apertures and the tungsten tertiary collimators (TCT) at the low-beta collision points. During the LHC beam commissioning, several machine protection tests were carried out to validate collimator setup and hierarchy at different beam energies and intensities. The outcomes of these measurements are presented in this paper together with the results of particle tracking simulations for asynchronous beam dump. These studies allowed to quantify the leakage expected from dump protection collimators to the downstream elements, and to validate the system performance towards higher beam intensity.