A Large Scintillating Screen for the LHC Dump Line

The 7 TeV proton beam from the LHC ring is ejected through a long transfer line to beam dump blocks, approximately 100m downstream of the ejection septa, a series of dilution kicker magnets provide a sweeping deflection spreading the extracted beam over a 40 cm diameter area on the face of the beam dump cores. During normal operation, the quality of each dump event must be recorded and verified. The so-called â€ﾜPost-Mortem” dataset will include information from the beam dumping system (logic signals, kicker pulses…) as well as from the beam diagnostics along the extraction lines. For this purpose, profile monitors in front of the dump blocks must be permanently available during machine operation. With more than 1014 protons stored in LHC, the energy deposited in the screen becomes an issue and thermalresistant materials have to be considered. In this paper, the design of this quite unusual device is presented. The different technical options considered for the choice of the screen material are discussed first. The complete layout of the installation is then described with a special emphasis on the mechanical design, the screen assembly and the choice of the radiation-hard camera used to observe the screen.