Evian December 12 14 th 2017 Beam dynamics

Evian, December 12 -14 th, 2017 Beam dynamics and levelling scenarios Y. Papaphilippou with input from F. Antoniou, G. Arduini, H. Bartosik, J. Boyd, R. Bruce, X. Buffat, R. de Maria, S. Fartoukh, M. Giovannozzi, M. Hostettler, G. Iadarola, N. Karastathis, E. Metral, D. Pellegrini, S. Papadopoulou, S. Redaelli, G. Rumolo, C. Schwick, R. Tomas, J. Wenninger

Considerations I q Injectors’ reach - Train composition, brightness q BCMS-25 ns (144 bunches), 1. 3 -1. 4 e 11 p, @ 1. 6 μm. rad q Emittance evolution q 10% BU at injection, 40% BU during the ramp -> 2. 5 μm. rad @ stable beams for BCMS q 0. 05 μm. rad/h BU in stable beams q Optics and collimation - min β* choice q Starting point β* of 30 cm q Consider advancing the telescopic part? q Working scenario with β* min. of 25 cm q Heat-load and e-cloud q Considering upper limit of 200 W/hcell, allowing ~1. 45 e 11 for BCMS 25 ns (2556 b. )

Considerations IΙ q Instabilities - Octupole, chromaticity, coupling, ADT q Octupole/chromaticity can be relaxed for colliding bunches. For non-colliding need high values (e-cloud) q Coupling well corrected (especially when tune approaching diagonal) q ADT gain high? q Beam-beam, Crossing angle, DA, tunes, lifetime q 150 μrad for 1. 3 e 11 provides adequate DA q Consider 160 μrad for keeping margin for higher intensity (1. 4 e 11), and/or extra emittance blow-up q Levelling scenarios - Beta*, crossing, Pile-Up q 1. 25 e 11, 30 cm, 160 μrad, peak lumi of 2 e 34, pile-up of 57 q x-ing angle anti-leveling q 1. 3 -1. 4 e 11, 30 cm, 160 μrad, virtual lumi of 2. 2 -2. 5 e 34, pile of 61 -71 q Level with separation at 2 e 34 q 1. 3 -1. 4 e 11, 25 cm, 160 μrad, virtual lumi of 2. 4 -2. 8 e 34, pile of 69 -79 q Level with beta* at 2 e 34 q 1. 3 -1. 4 e 11, 25 cm, 150μrad, virtual lumi of 2. 6 -3 e 34, pile of 72 -82 q Level with beta* at 2 e 34

Scenarios for 2018 q 1. 25 e 11, 30 cm, 160 μrad, peak lumi of 2 e 34, pile-up of 57

Scenarios for 2018 q 1. 3 -1. 4 e 11, 30 cm, 160 μrad, virtual lumi of 2. 22. 5 e 34, pile of 61 -71, level by seperation

Scenarios for 2018 q 1. 3 -1. 4 e 11, min beta* of 25 cm, 160 μrad, virtual lumi of 2. 4 -2. 8 e 34, pile of 69 -79, Level with beta* at 2 e 34

Scenarios for 2018 q 1. 3 -1. 4 e 11, min beta* of 25 cm, 150μrad, virtual lumi of 2. 6 -3 e 34, pile of 72 -82, Level with beta* at 2 e 34

Scenarios for 2018 q BCS, 1. 3 -1. 4 e 11, for 1. 8μm. rad, min beta* of 25 cm, 150μrad, virtual lumi of 3. 1 -3. 6 e 34, pile of 86 -100, Level with beta* at 2 e 34

Comparison Parameter. Beam energy in collision [Te. V] Particles per bunch, N [1011] Number of bunches per beam Number of collisions in IP 1 and IP 5* Crossing angle in IP 1 and IP 5 [μrad] Minimum β* [m] en [μm] εL [e. Vs] R. M. S. bunch length [cm] Virtual peak luminosity Lpeak [1034 cm− 2 s− 1] Max pile-up Levelling time [h] Maximum number of bunches per injection Lint [fb-1/day] BCMS 30 cm 25 cm 320 μrad – 300 μrad – no – sep. β* – β* levelling 6. 5 1. 25 1. 3/1. 4 2556 2544 320 300 0. 3 0. 25 2. 2 8. 3 2. 0 57 0. 0. 99 2. 2/2. 5 61/71 1. 25/3. 25 2. 4/2. 8 69/79 2. 75 /4. 75 144 1. 06/1. 18 1. 15/1. 25 2. 6/3. 0 72/82 3. 25/5. 25 1. 17/1. 26

On-going q Consideration for lumi-loss from emittance growth, reduced lifetime q Beta* with x-ing angle adaptation q Gain from x-ing angle anti-levelling q Other beam flavours: Standard 25 ns, 8 b 4 e