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Modulated RILIS heating - small project proposal

The performance of the LHC Beam Dump System (LBDS) during Run 2 beam operations are presented in terms of rate and type of failures of the extraction (MKB) and dump (MKD) kickers. New faults were also identified and they are described together with their impact on the beam distribution at the dump protection elements and the TDE assembly. Foreseen and proposed mitigations, on the MKB/MKD magnets, generators, and controls, in order to minimise possible beam intensity and brightness limitations, are addressed. The reasons and functionality of the BETS TCDQ are reminded together with the present operational constraints, which will still hold in Run 3. Main changes and issues encountered with the XPOC analysis and acknowledgment procedure are treated. Updates are given on the operational experience with the variable AGK after the accidental injection of bunches in the abort gap in 2017. The evolution of the execution and validation procedure for the asynchronous beam dump test and the further planned improvements are covered. Finally, recommendations are given for a proper scheduling of the LBDS commissioning time after LS2.

During 2016 operation, all beam dump requests were properly executed by the LBDS. Nevertheless, many redundant failures in LBDS subsystems occurred, leading to LHC downtime. In this talk, some LBDS operational statistics for 2015 and 2016 are compared. Details are given on the main recurrent failures of LBDS and the foreseen corrective actions. The various Reliability Runs and Dry Runs planned for the EYETS are explained, as well as the LBDS needs for cold-checkout and recommissioning at start-up.

Substantial upgrades were carried out to the MKI beam screen during LSl: MKI heating has not lirrrited LHC operation since LSl, and is not expected to do so during Run 2. Similarly, during LSl, the vacuum systems on the interconnects between MKl magnets were upgraded: as a result there haven't been any issues with SIS vacuum thresholds on the interconnects between adjacent MKls. However, during 2016, dynamic pressure increase on the MKISD-QS interconnect limited the number of bunches that could be injected for Beam 2. The MKIZD kicker magnet caused several issues during 2016, including limiting the length of the field pulse from August onwards and a high impedance contact from October. As a result of firrther deterioration of the high impedance contact the MKIZD was exchanged during TS3. During November the Surveillance Voltage Monitoring system interlocked the MKIZ installation on several occasions. This paper reviews the MKI performance during 2016, the plans for the EYETS and the expected performance during 2017.

This Report gives a full description of the ELENA Ring to be built within the circumference of the Antiproton Decelarator (AD) Ring, in Building 193 at CERN. The ELENA ring will further decelerate the antiprotons coming from the AD at the momentum of 100 MeV/c down to 13.7 MeV/c, which corresponds to the kinetic energy of 100 keV before extracting to the physics experiments in the same building. The history of such an extra low energy antiproton ring at CERN goes a long way back, and even to the Decelerator’s previous incarnation, the Low Energy Antiproton Ring (LEAR), which came into operation in 1983. Already at that time, there were physics’ requests to further decelerate the antiprotons expected from LEAR by proposals for ELENA. Appendix I illustrates the cover pages of two such CERN documents from 1982.