| Preprint | |
| Report number | CERN-ACC-2020-0028 |
| Title | Combined ramp and telescopic squeeze |
| Author(s) | Fartoukh, Stephane (CERN) ; Azzopardi, Gabriella (CERN) ; Bruce, Roderik (CERN) ; Buffat, Xavier (CERN) ; Coello De Portugal - Martinez Vazquez, Jaime Maria ; Fuster Martinez, Nuria ; Iadarola, Giovanni (CERN) ; Karastathis, Nikos ; Kostoglou, Sofia (CERN) ; Maclean, Ewen Hamish (CERN) ; Malina, Lukas (CERN) ; Mereghetti, Alessio ; Mirarchi, Daniele (University of Manchester (GB)) ; Persson, Tobias Hakan Bjorn (CERN) ; Pojer, Mirko (CERN) ; Poyet, Axel (Universite Grenoble-Alpes (FR)) ; Salvachua Ferrando, Belen Maria (CERN) ; Schaumann, Michaela (CERN) ; Solfaroli Camillocci, Matteo (CERN) ; Sterbini, Guido (CERN) ; Tomas Garcia, Rogelio (CERN) ; Valuch, Daniel (CERN) ; Wegscheider, Andreas (Hamburg University (DE)) ; Wenninger, Jorg (CERN) |
| Publication | 2020 |
| Imprint | 15 Aug 2020 |
| Number of pages | 40 |
| Subject category | Accelerators and Storage Rings |
| Accelerator/Facility, Experiment | CERN LHC |
| Keywords | LHC Run 3 ; ATS scheme ; Combined ramp and tele-squeeze |
| Abstract | This paper highlights the outcome of the 2018 round ATS MD program, which aimed at demonstrating the feasibility of a combined ramp and telescopic squeeze as a potential key ingredient to operate the machine in Run 3, with much brighter and more energetic beams with respect to Run 2. The machine configuration which was used is first described in terms of hypercycle, optics transitions, and dedicated beam gymnastics. The various commissioning steps which were needed to obtain the green light for an intensity ramp up are described, in particular the optics measurements and corrections, the triplet aperture measurements, and the collimation-related activities. The main results are illustrated in terms of octupole threshold minimization, beam lifetime in the ramp with the machine filled with several hundred of nominal bunches or 8b4e bunch trains, and long-range beam-beam mitigation with lattice octupoles. A dedicated instability study on possible variants for the adjust beam process is also reported. |
| Submitted by | [email protected] |
Record created 2020-10-27, last modified 2020-10-30
