FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies

Transcription

1 FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies Jose L. Abelleira, Leon Van Riesen Haupt, Andrei Seryi, Emilia Cruz Alaniz (JAI-FCC team) Thanks to the CERN FLUKA team 10 th April 2018 FCC Week 2018, Amsterdam

2 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 2 CONTENTS Flat beams Alternative triplet Alternative optics Energy deposition : dose in triplet Energy deposition : crossing angle adjustment Energy deposition : dose in dipole separators

3 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 3 In the FCC, the beam-beam parameter can rise above 0.03, due to the strong radiation damping. (ε N, ξ ). If we want to control this parameter (ξ total <0.03), noise blow up must be introduced. In this context, flat beams (β x, β y ) can offer some advantages: Reduce the beam-beam parameter Reduce the angle (for the same beam-beam separation, Δ in ) * Reduce Piwinski angle as σ in crossing plane is enlarged As the crossing angle is reduced: Flat beams The impact of not having crab cavities is lower The radiation debris is less spread Alternative to crab cavities Ѳ = Δ in ε/β x J.L. Abelleira, talk: HE-LHC with flat beams. * However, Δ in must be increased for flat beams: T. Pieloni, talk: Beam-beam effects

4 Flat beams Parameters of the flat beam optics, compared to the round optics: Round nominal Round ultimate flat Particles per bunch N [10 11 ] 1.0 Normalized emittance ε N [μm] 2.2 Number of bunches nb Bunch length σ l [cm] 8 IP beta, function, hor β x * [m] IP beta function, ver β y * [m] Full crossing angle Ѳ [μrad] Beam-beam separation Δ in [σ] Crab-cavities no yes no Piwinski angle Ф (0) 0.65 Event Pile up Geom. Luminosity reduction factor S Total Beam-beam parameter, initial ξ 0 [10-3 ] Initial luminosity L 0 [10 34 cm -2 s -1 ] Peak luminosity L peak [10 34 cm -2 s -1 ] Integrated luminosity L int [fb -1 /day] * 7.2 *6.3 without crab-cavities, 7.6 with crossing angle reduction FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 4

5 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 5 Time evolution comparison for luminosity, beam-beam parameter and integrated luminosity. Flat beams Artificial emittance blow-up ξ T = ξ x + ξ y ξ T =2*max(ξ x,ξ y ) (HH crossing, worst case)* ξ x first dominant, then ξ y *T. Pieloni, talk: Beam-beam effects

6 Alternative triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 6 Triplet optimization to minimize energy deposition Set required β*, L* and use initial shielding. Use code to find shortest setup with good beam stay clear Use this setup for radiation studies of triplet Integrate and match into machine for further studies Change shielding accordingly Work out shielding required for this setup Leon Van-Riesen Haupt, poster An Optimised Alternative Triplet for the Final Focus of the FCC-hh with a 40m Final Drift.

7 Alternative triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 7 Nominal triplet L*=40 m Q1 Q2 Q3 14.3m 12.5 m 14.3 m Alternative triplet 15 m 15 m 15 m IP The alternative triplet is used for the flat and for the round optics. 4 m shorter

8 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 8 Alternative triplet Q1 Q2 Q3 g [T/m] coil, r [cm] free aper, r [cm] Abs thickness [cm] Q Q Q Comparison with nominal triplet g [T/m]

9 β [km] β [km] Alternative triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 9 orbit [m] 21.6σ β * =0.3 m (round optics) Leon Van-Riesen Haupt, poster. β * x=1.2 m, β * y=0.15 m (flat optics) orbit [m] 20.2σ

10 Energy deposition: dose in triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 10 Dose profile in each magnet

11 Energy deposition: dose in triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 11 ROUND (Ѳ=176 μrad) (values normalized to L int =10 ab -1 ) 50% Vert. Crossing 50 % Hor. Crossing FLAT (Ѳ =114 μrad) For a total of 18.5 ab -1, peak doses: <65 MGy (round) <45 MGy (flat) <37 (combined).

12 Energy deposition: dose in triplet FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 12 ROUND Peak power density in coils, below 5 mw/cm 3. FLAT

13 Energy deposition: cross. angle adjustment FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 13 For the round case, β * =0.3 m, if the angle is reduced with emittance as Ѳ = 15 ε/β x With regard to the nominal ultimate round without crab cavities (β * =0.3 m, crossing angle 15σ), the luminosity is slightly larger than for flat beams (7.6). As the dose from collision debris depends on angle, this can reduce the total dose (Half of the luminosity production is provided with a crossing angle < 80 μrad).

14 Energy deposition: cross. angle adjustment FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 14 Dose reduction, largest for Q3 Same exercise reducing shielding to 2.4 cm in all quadrupoles.

15 Energy deposition: dose in dipole separators FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 15 FLUKA model developed at JAI-Oxford D1, based on MBXW D2, based on MBW TAN mode included for the simulations (Provided by CERN FLUKA team). 17 cm 8 cm Alternative triplet D1 (x3) D2 (x3) Complete IR layout

16 Energy deposition: dose in dipole separators FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 16 D1 D2

17 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 17 Round beams D1 Dose in dipole coils for flat beam D2 Flat beams D1 D2

18 Conclusions FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 18 Flat-beams advantages: less pile-up (-30%), more even luminosity, no crabcavities, no need for noise injection. Flat-beam disadvantage: less integrated luminosity (-20%). Flat beam has marginal loss in physical aperture (21.6σ 20.2σ). Flat beams good option if not crab-cavities. The alternative triplet is more compact than the nominal one, and can deliver both round and flat beams. Beam-beam studies ongoing (T. Pieloni et al). For triplet: total dose below 30 MGy for 10ab -1, peak power below 5 mw/cm 3. Radiation in dipole separators reasonable without shielding, and different profile at both sides.

19 FCC Week 2018, Amsterdam FCC-hh Final-Focus for Flat-Beams: Parameters and Energy Deposition Studies 19 Thank you for your attention