Bernhard Holzer, CERN-LHC Parameter Space for HL-LHC IR8 * IP5 IP1 IP2 IP8 LEB Meeting

HL-LHC Parameter Table

Luminosity: *F * H F = geometric los factor (x-angle) H = hour glass effect LHC StandardHL-LHC 25nsHL-LHC 50ns N p 1.15* * *10 11 nbnb β*3 m3 -10 m εnεn 3.75 μm2.5 μm3.0 μm σ18 μm7.6 μm8.3 μm

a large variety of beam optics studied & optimised in IP8 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 each optics has to be „implemented“ into the overall LHC lattice & optics. IR8 optics, 3m, ATS matched

HL-LHC Luminosity in IR8 LHC_Standard, β*= 3m, ε = 3.75 μrad HL-LHC, β*= 3m, Δt = 50ns, ε = 3.0 μrad HL-LHC, β*= 3m, Δt = 25ns, ε = 2.5 μrad HL-LHC, β*= 10m, Δt = 25ns, ε = 2.5 μrad nota bene: values refer to E = 7TeV The optics foreseen in the HL-LHC concept fot to the expected Luminositybin IR8.

HL- LHC-IR8-”Standard Lumi settings”: envelopes refer to +/- 5 σ crossing angle vert. 100 μrad β* = 3.0 m, ε n =3.0 μm, on_LHCb = 1.0  135 μrad hor hor plane... dominated by LHCb crossing effect “neg polarity”, sufficient sep. at 2, 3 encounter but cross over due to “wrong” LHCb polarity Crossing Angles and Loss Factor

vert. plane... guarantees separation from encounter #2. Crossing Angles and Loss Factor: 3m Optics HL- LHC-IR8-”Standard Lumi settings”: envelopes refer to +/- 5 σ crossing angle vert. 100 μrad β* = 3.0 m, ε n =3.0 μm, on_LHCb = 1.0  135 μrad hor

vert. plane... guarantees separation from encounter #2. A vertical crossing angle of 100μrad guarantees sufficient separation at all parasitic encounters =in a range of beam optics between m. Crossing Angles and Loss Factor: 10m Optics HL- LHC-IR8-”Standard Lumi settings”: envelopes refer to +/- 5 σ crossing angle vert. 100 μrad β* = 10.0 m, ε n =3.5 μm

HL- LHC-IR8-”Standard Lumi settings” crossing angle vert. 100 μrad β* = 3.0 m, ε n =3.0 μm,  135 μrad hor Crossing Angle and Loss Factors *F * H F F ≈ 98 % H ≈ Geometric Loss Factor: Hour Glass Effect... for nominal LHC parameters

HL- LHC-IR8-”Standard Lumi settings: ”Aperture “after LS2” crossing angle vert. 100 μrad β* = 3.0 m, ε n =3.75 μm on_LHCb = 1.0  135 μrad hor n1 ok Crossing Angles and Optics: Aperture Velo not included

HL- LHC-IR8-”HL- Lumi settings: ”Aperture “after LS2” crossing angle vert. 100 μrad β* = 10.0 m, ε n =3.75 μm on_LHCb = 1.0  135 μrad hor n1 ok nota bene: 10m optics is NOT combined with ATS scheme Crossing Angles and Optics: Aperture Velo not included

Addendum

LHCb Polarity & Horizontal Crossing Angle collisions at IP, separation at paras. encounters #2,3 collisions after LHCb compensator dipole collisions at IP, separation at paras. encounters #2,3 via LHCb separation after paras. encounters #3 via ext. bump LHC-IR8-Original Design: Combination of internal (LHCb-) angle and external angle LHCb = “good” (... negative kick on beam 1) LHCb = μrad b1 on_x8 = on_x8=0.275 ≈ -66μrad horizontal plane

LHCb Polarity & Horizontal Crossing Angle collisions at IP, separation at all paras. encounters as the external bump overcompensates the effect of the LHCb dipole (nota bene: aperture need !!) LHC-IR8-Original Design: Combination of internal (LHCb-) angle and external angle LHCb = “bad” (... positive kick on beam 1) LHCb = μrad b1 on_x8 = μrade horizontal plane eff crossing angle = -100μrad LHCb

LHCb Polarity & Horizontal Crossing Angle Aperture: β*=3.0m, ε n =3.75 μrad LHCb = “good” LHCb = “bad”

eff crossing angle = mrad collisions at IP, separation at all paras. encounters Injection: horizontal crossing-angle LHCb = “good” (... negative kick on beam 1) LHCb = mrad b1 on_x8 = μrad separation at IP via vert. 2mm sep bump horizontal plane vertical plane

eff crossing angle = mrad Injection: horizontal crossing-angle LHCb = “bad” (... positive kick on beam 1) LHCb = mrad b1 on_x8 = μrad horizontal plane collisions at IP avoided via vert. sep bump due to cross over effect separation at all paras. encounters not possible for 25ns operation

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

crossing angle y’=107μrad emittance ε n =2.5 closed orbit tolerance 3.0mm Aperture Injection: vertical crossing-angle LHCb = “bad” (... positive kick on beam 1) LHCb = mrad on_sep8 = Δx=2.0mm on_x8vi = y’ = 125 μrad default: cor=4mm, en=3.75 optimistic (?): cor=2mm, en=2.5