LHC Physics Debris Simulation Update L. Nevay Many thanks to: A. Mereghetti, D. Mirarchi, A. Abramov, R. Bruce 3rd May 2019

Introduction Measured doses in arcs appear correlated with luminosity and not with stored beam intensity See: ColUSM 9 talks (ColUSM meetings website) IPAC Paper by D. Mirarchi - http://inspirehep.net/record/1470240 LMC #331 - talk by R. Garcia Alia Extend work to simulate for recent optics and for HL-LHC Previously presented simulations using Sixtrack only and now with Sixtrack-FLUKA coupling see LHC Collimation Working Group #238

Previous Simulations - Recap Previous simulations using Sixtrack to predict rate of protons 2017 2016

Simulation Setup Using Sixtrack-FLUKA coupling ExtendedSource branch Special 0.5m 'pipe' insertion for each IP in (1,5,8) Inelastic / elastic collisions forced in this region Beam generated at IP and back propagated 0.25m no energy spread in original beam into simulation 12 scenarios per map B1,2 x IP 1,5,8 x inelastic,elastic Simulate 5M particles for each scenario up to 200 turns Momentum cut of 30% from nominal for tracking aim is to look far from IPs (ie not immediately at triplets) Perfect machine used 2017, β*=40 cm, θ=150 µrad optics used initially Luminosities used: IP 1& 5: 1.5 x 1034 cm2 s-1 IP 8: 0.05 x 1034 cm2 s-1

p-p Cross-Section for Event Rate Previously √s = 8 TeV data extrapolated to √s = 14 TeV : G. Antchev et al., Phy. Rev. Lett., vol. 111, 012001, Jul. 2013. J. R. Cudell et al., Phy. Rev. Lett., vol. 89, 201801, Oct. 2002. Current measurments for √s = 13 TeV: The CMS collaboration, Sirunyan, A.M., Tumasyan, A. et al. J. High Energ. Phys. (2018) 161.  M. Aaboud et al. (ATLAS Collaboration), Phys. Rev. Lett. 117, 182002 (2016) arXiv:1712.06153 (TOTEM elastic & inelastic) S.M. Stark, EPJ Web of Conferences 141, 03007 (2017) (summary) arXiv:1803.10974 (LHCb inelastic) Experiment σ p-p inelastic (mb) σ p-p elastic (mb) ATLAS 78.1 ± 2.9 24.33 ± 0.39 CMS 71.3 ± 3.5 TOTEM 79.5 ± 1.8 31.0 ± 1.7 LHCb 75.4 ± 4.5 using these values Don't know the exact ones inside FLUKA but approximately ok for scaling

Distributions Looking just after the insertion for inelastic collisions ~14.5% transmitted into model Change in angle due to interaction Previous method

Total Loss Map Combined B1&2 for IP 1,5,& 8 for inelastic Elastic had nearly no loss at all in some cases, no losses at all after 20k turns not shown here as negligible contribution IP1 Source Integrated Power (W) Cold 154.76 Warm 98.14 Collimator 6.44 Total: 259.34 Note: - all IPs -> ~2.5kW burning off in beam

Losses From IP1 Looking at the contribution from each IP individually Source Integrated Power (W) Cold 62.01 Warm 62.04 Collimator 3.30

Losses From IP5 Source Integrated Power (W) Cold 89.62 Warm 34.59 Collimator 2.92

Losses From IP8 Source Integrated Power (W) Cold 3.13 Warm 1.16 Collimator 0.21

Sector 1-2 Identify particular cells of losses in Sector 1-2 IP1 IP2 MB.13R1.B1 IP1 IP2 MQ.16R1.B1 MB.A18R1.B1 MBC28L2.B1 MQ.27L2.B1 MQ.23L2.B1 MQ.19L2.B1 MQ.15L2.B1 MQ.16R2.B1 MQ.21R1.B1 MQ.25R1.B1 Mostly from IP5 Mostly from IP8 Mostly from IP1

Right of IP1 Looking closer at IP1 right side IP1 MB.C13R1.B1 MB.B11R1.B1 IP1 From IP1

IP4 - IP6 Major arc spikes nearly all from IP5 IP4 IP5 IP6 MQ.23L6.B1 MQ.15R4.B1 MQ.23R4.B1 MQ.29L5.B1 MQ.21L5.B1 MQ.20R5.B1 MQ.29R5.B1 Mostly from IP5 Mostly from IP8 Mostly from IP8 Mostly from IP1

About IP8 One significant spike IP8 MB.C16L8.B1 MB.B14L8.B1 Direction of B1

Comparison From LMC #331 - talk by R. Garcia Alia

Analysis (my) previous analysis didn't weight by energy correctly Rewritten event-by-event analysis Ongoing development for traceback of losses primary or secondary hit aperture? how many collimators (if any) before interaction aperture impact due to teritiary particles?

Summary 2017, β*=40 cm, θ=150 µrad scenario simulated for perfect machine Some spikes similar to measurements Possible to simulate further scenarios quickly Analysis development will allow more detailed trace-back will help with possibly mitigating the losses

Thank you