Preliminary design of the new Proton Synchrotron Internal Dump core

The luminosity of the LHC particle accelerator at CERN is planned to be upgraded in the first half of 2020s, requiring also the upgrade of its injector accelerators, including the Proton Synchrotron (PS). The PS Internal Dumps are beam dumps located in the PS accelerator ring. They are safety devices designed to stop the circulating proton beam in order to protect the accelerator from damage due to an uncontrolled beam loss. The PS Internal Dumps need to be upgraded to be able to withstand the future higher intensity and energy proton beams. The dump core is a block of material interacting with the beam. It is located in ultra-high vacuum and moved into the beam path in 150 milliseconds by an electromagnet and spring-based actuation mechanism. The circulating proton beam is shaved by the core surface during thousands of beam revolutions. The preliminary new dump core design weighs 13 kilograms and consists of an isostatically pressed fine-grain graphite and a precipitation hardened copper alloy CuCrZr. The core is cooled by stainless steel water circuits. The mechanical integrity of the core is studied under proton beam impact. The temperatures and stresses induced by specified beam dumping scenarios are simulated with ANSYS finite element software, coupled with heat generation input from FLUKA simulations. The fatigue and radiation damage due to repeated beam impacts is also studied. The simulated temperatures in the core stay below the material limits and the stresses stay within the elastic regimes, with high safety factors in CuCrZr, but low safety factors in graphite. Graphite fatigue may limit the lifetime of the core. The radiation damage levels in the core materials are considered low. Overall, the preliminary core design fulfills the requirements set and the design can proceed towards prototyping and eventual installation in 2020.