An upgrade of the passive protection system in the LHC injection transfer lines (TI2 and TI8) is required to safely bring the LHC into the high luminosity era. In accordance with the LHC Injectors Upgrade (LIU) project, the LHC will require beams from the injectors with a brightness much increased with respect to even the ultimate LHC intensity.

A sophisticated machine protection system has been put in place to protect the transfer lines and especially the LHC from damage in case of erroneous transfer. The present system is based on a set of passive absorber blocks with moveable jaws (TCDI, Target Collimator Dump Injection) and designed to attenuate the LHC ultimate beam intensity to safe levels.

A set of 6 passive TCDI absorbers is located at the end of each of the approximately 3 km long injection lines to protect the LHC in case of failures during the extraction process from the LHC’s last pre-injector (the SPS) or in the beam transfer lines themselves. The collimators protect the tight injection septum (MSI) aperture, the injection region and the LHC cold aperture against bending errors upstream, and were therefore placed towards the end of the line: in case of an erroneous transfer, the TCDI absorbers have to attenuate the beam to a safe level and be robust enough to survive the impact.

The original TCDI positions and optics in TI2 fulfill the LIU constraints. However, the present optics (Q20 SPS to LHC optics) in TI8 does not satisfy all the constraints imposed by LIU. As a result, the optics in TI8 was re-matched and the TCDIs repositioned as the line is more constrained for space. Two additional power supplies will be required to re-match the optics to meet the LIU constraints: the extra power supplies will power quadrupoles MQIF.87000 and MQID.87100, which were previously powered in series as part of the FODO channel (circuits RQIF.80400 and RQID.80500).

Project coordinator: Matthew Alexander Fraser

EPC Responsible: Gilles Le Godec
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Deliverables: COMET_2p