1 / 21

HL-LHC Optics Configuration vs. Experiment Desiderata

HL-LHC Optics Configuration vs. Experiment Desiderata. Bernhard Holzer for the WP2, Task2.2 Team B. Dalena , A. Bogomyagkov , R. Appleby, A. Fauss-Golfe , J. Payet , A. Chance’, K. Hock, M. Korostelev , R. deMaria , J. Resta , C. Milardi , L. Thompson, M. Thomas, A. Wolski.

velika
Download Presentation

HL-LHC Optics Configuration vs. Experiment Desiderata

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. HL-LHC Optics Configuration vs. Experiment Desiderata Bernhard Holzer for the WP2, Task2.2 Team B. Dalena, A. Bogomyagkov, R. Appleby, A. Fauss-Golfe, J. Payet, A. Chance’, K. Hock, M. Korostelev, R. deMaria, J. Resta, C. Milardi, L. Thompson, M. Thomas, A. Wolski

  2. HL-LHC Parameter List x-angle β* ε L0

  3. Luminosity & Loss Factor * R ideal luminosity formula ★★★★★★ loss factor due to crossing with an angle (pure geometric effect ... but large) R * H ≈ 0.33

  4. Luminosity & Beam Optics • The HL-LHC Lattice & Optic has to establish β* at IP1 & 5 to reach a • “virtual luminosity” of • and for the given bunch intensities this means • to small for the IR1 / 5 • matching section • squeeze starts at neighboring • sectors (“ATS”) . IP8 IP2 IP1

  5. HL-LHC Wish-List of the Experiments Establish a set of different beam optics (i.e. β*) that combines the HL-LHC options in IR1,5 with the boundary conditions for IR2, IR8. set up four baseline optics based on assumptions on aperture & magnet technique 170

  6. HL-LHC Wish-List of the Experiments to be discussed ... within WP2 & Experiments

  7. HL-LHC Beam Optics ... and as latest version: 150mm Triplet Aperture / 140T/m Gradient Problem & Solution: ATS combines the different LHC Interaction Regions. a large variety of beamopticsstudied & optimised in IP8 / IP2 bog_150_0100_0100_3000_3000.madx β*(IP8) = 3m standard ATS, round bog_150_0050_0200_3000_3000.madx β*(IP8) = 3m standard ATS, flat_xy bog_150_0050_0200hv_3000_3000.madx β*(IP8) = 3m standard ATS, flat_yx bog_150_5500_5500_10000_10000.madx β*(IP8) = 10m ATS_injection bog_150_0400_0400_0500_0500.madx β*(IP8) = 50cm ATS ions eachoptics has to be„implemented“ intotheoverall LHC lattice & optics. court. A. Bogomyagkov

  8. HL-LHC Optics in IR2 the “ATS Squeece Optics (15cm/15cm/10m/10m) IP1, ATS Optics IP2 IP3, Standard FoDo Optics Find an otpics solution that is feasible for the Luminosity upgrade and guarantees adequate conditions for the ALICS and LHCb experiment at the same time.

  9. HL-LHC optics: injection to proton collisions Injection optics IR8 b*=10 m IR1 b*=5.5 m IR2 b*=10 m IR4 IR5 b*=5.5 m IR6 Transition to pre-squeeze optics IR8 b*=3 m IR1 b*=0.4 m IR2 b*=10 m IR4 IR5 b*=0.4 m IR6 ATS to collision optics IR8 b*=3 m IR1 b*=0.15 m IR2 b*=10 m IR4 IR5 b*=0.15 m IR6 250 - 300 fb-1 per year

  10. HL-LHC Optics in IR1, 5 find a smooth transition without (too many) hysteresis problems Standard low-beta-Squeeze ATS-Squeeze 5.5m injection optics 40cm pre-squeeze optics 15cm ATS optics

  11. HL-LHC Optics in IR1, 5 court. M. Korostelev Optics Transition via ATS is “smooth by definition”. Optics Transition Injection – Pre-Squeeze needs TLC optimisation

  12. Lattice, Loss Factor & Crab Cavities * F F Optimse the lattice (i.e. quad positions) to gain crab effectiveness.

  13. LatticeOptimisation for Crab Cavities court. B. Dalena Study of additional quadrupoles at Q5 / Q6 / Q7 ... Q4 / Q5 / Q6 in triplet configuration & add. Q7 ... allows for much larger βs at the Crab Cavities add. Quad at Q5: no big change additional k-strength needed at Q7

  14. Lattice & Crab Cavities court. B. Dalena et al increase the beta function at the location of the crab cavities space needed for crab cavity installation enhanced β function needed for crab cavity effectiveness re-shuffling the matching quads, strengthening Q7 (170T/m, 15cm Otpics)

  15. Lattice & Crab Cavities court. R. DeMaria Standard Bump for Crossing angle & beam separation closes at Q5 ... and leads to (varying) orbit offsets at the crab cavity location. -> bump closure by strong dipole magnet at D2. -> Alternative: transverse cavity positioning feedback following the beam orbits

  16. Crossing Angles & Apertures Increasing β-function in the mini-beta drift leads to large crossing angles ... to avoid parasitic bunch encounters. s s * β0 crossing angle bump for the case: β=15 cm, ε=3.0μm, +/- 10σ

  17. Crossing Angles & Apertures IR1 & 5 crossing angle bump for the case: β=15 cm, ε=3.0μm, +/- 10σ with location of parasitic 25ns encounters Aperture need determined by optics, emittance, orbit tolerances, crossing angle WORK IN PROGRES, LEB-Meetings M.Gallilee

  18. Special Problem: 25ns at IR8 Injection: horizontal crossing-angle LHCb= “good” (... negative kick on beam 1) LHCb = -15.5 ... -2.1mrad b1 on_x8 = +1.0 .. -170μrad eff crossing angle = -2.27 mrad horizontal plane vertical plane collisions at IP, separation at all paras. encounters separation at IP via vert. 2mm sep bump

  19. Injection: vertical crossing-angle LHCb = “bad” (... positive kick on beam 1) LHCb = +15.5 ... +2.1mrad on_sep8 = +1.0 ... Δx=2.0mm on_x8vi = 0.8 ...... y’ = 125 μrad avoids crossing at IP and paras. encounters 1,2,3 separates the beams from paras. encounters 4 optimisation of crossing angle (keep it SMALL) y’=107μrad emittance (keep it SMALL) εn =2.5 closed orbit tolerance (keep it SMALL) 3.0mm horizontal plane vertical plane collisions at IP avoided via hor. sep bump separation ok at paras. encounters 2...4

  20. Open Questions • Which baseline optics to choose ... hardware R&D will tell • Follow up of magnet development • Do we need a 1km Optics ?? • Finally ... the leveling Problem: • β* leveling in IP 1 & 5 ... • but then a synchronous β* leveling in • IR2 & IR8 will be DIFFICULT IP2

  21. Open Questions • Finally ... the leveling Problem: • β* leveling via crab cavity voltage (i.e. crossing angle) • changing the crossing • angle reduces the luminosity • but does NOT reduce the • density of vertices inside • the “luminous region”. • β* leveling via closed Orbit Bumps • -> special magnets needed (orbit in Crab Cavities) • -> beam beam problem ? 2 vertices 20 vertices

More Related