On behalf of the FLUKA team Simulating proton/ion-induced particle showers in the Large Hadron Collider E. Skordis, C. Bahamonde, F. Cerutti, A. Ferrari, A. Lechner, A. Tsinganis, V. Vlachoudis On behalf of the FLUKA team SATIF-13 12/10/2016 E. Skordis

LHC overview 500 kW Beam loss 2*362 MJ total energy stored in both LHC beams (2808 bunches)*(1.15*1011protons/bunch)*(7*1012eV/proton)*(1.602*10-19Joules/eV) = 362 MJ per beam ̴4000 Beam Loss Monitors are installed in the LHC each capable of triggering a beam dump if the dose exceeds a certain threshold LHC collimation system: > 100 movable devices Capable of cleaning up to 500 kW Betatron cleaning: IR7, momentum cleaning: IR3 Not all power is absorbed by the collimators themselves 500 kW Beam loss SATIF-13 12/10/2016 E. Skordis 2

LHC Beam losses Regular losses (slow, partially controlled) Beam intercepting movable devices (collimators, active absorbers, etc…) -> beam cleaning, magnet protection Particle collisions at experiments (shower debris, mostly ) Simulated values of interest Dose to BLMs -> simulation validations Dose to equipment -> long term damage Peak power density -> short term limitations (magnet quenchs) Other kind of losses not presented here Beam interaction with residual gas Irregular losses (fast, uncontrolled) Accident scenarios <- failure or misbehaviour of accelerator elements (magnets, RF, collimators etc..) UFO’s etc. SATIF-13 12/10/2016 E. Skordis

Energy deposition simulation requirements for collimation losses Creating source term for further FLUKA simulations SixTrack-FLUKA Coupling provides input. Map of particles arriving at the collimators SixTrack : Single particle 6D tracking code for long term tracing in high energy rings -> online coupling with FLUKA handling the interactions with collimators FLUKA simulation set up Model complex geometries of all key elements of the LHC Set up the simulation parameters Source routine Magnetic fields routines Physics settings Scoring Etc… FLUKA MODEL LHC BLM Picture Tracking for Collimation Workshop 30/10/2015 E. Skordis

Primary Beam 2 Collimators IR7 FLUKA geometry Long Straight Section Primary Beam 2 Collimators MQWA.C4R7 MQWA.D5R7 MBW.A MBW.B MQWA.E4R7 MQWA.E5R7 Last TCLA Left Dispersion Suppressor + Arch up to cell 14 SATIF-13 12/10/2016 E. Skordis

Collimator Support + Tank IR7 FLUKA - Sixtrack Simulation IP7 MQW4 MBW5 MQW5 % TeV TCP+TCSG Jaws TCAP MBW MQW Beam 2 Pipe Environment E -> m + Neutrinos Leaving 4 10 12.9 8.5 9.5 8.6 41.6 6.2 2.7 6.5 13.4 12 40.1 5.5 1.9 TCAP.A Enviroment Air Concrete Tunnel Tunnel Cables Collimator Support + Tank Beam Pipe supports Other Elements 40.1 += 0.5 30.5 0.9 3 1 4.2 Beam 2 Primary Collimators Beam 2 Direction SATIF-13 12/10/2016 E. Skordis

IR7 MBWA - MBWB 7 TeV Peak Dose profile Beam 2 MQWA.C4R7 MQWA.E4R7 MQWA.D5R7 MQWA.E5R7 MBW.A MBW.B TCAP Beam 2 SATIF-13 12/10/2016 E. Skordis Normalization: 1.15 1016 p (40 fb-1 )

IR7 MQW 7 TeV Peak Dose profile Beam 2 MQWA.C4R7 MQWA.E4R7 MQWA.D5R7 MQWA.E5R7 MBW.A MBW.B TCAP Beam 2 SATIF-13 12/10/2016 E. Skordis Normalization: 1.15 1016 p (40 fb-1 )

IR7 2013 Collimation Quench Test FLUKA – Sixtrack Simulations TCP TCP Beam 1 Q4 IP7 Q5 BLM integration Time : Running Sum 1 (40 μs) SATIF-13 12/10/2016 E. Skordis

IR7 2015 Evaluating collimation losses TCP Q4 Beam 1 Col 5.5e+14 p*/ ~4.3 fb-1 p* = 2015 equivalent 7 TeV proton lost Q5 Beam 2 IP7 6.5 TeV FLUKA-Sixtrack simulations SATIF-13 12/10/2016 E. Skordis

IR7 2015 Evaluating collimation losses MBW 6.5 TeV FLUKA-Sixtrack simulations SATIF-13 12/10/2016 E. Skordis

IR7 2015 Evaluating collimation losses Q4 Q5 MBW TCP IP7 6.5 TeV FLUKA-Sixtrack simulations SATIF-13 12/10/2016 E. Skordis

pp debris from the experiments Energetic secondary particles emitted in forward direction can escape experimental region Give rise to significant power deposition in the final focus regions (inner triplet Q1-Q3) Challenging upgrade in the HL era: 1.4x1034 cm-2 s-1 -> 5x1034 cm-2 s-1 SATIF-13 12/10/2016 E. Skordis

pp debris from the experiments BLM benchmark 2016 Collisions at 13 TeV (CM) Peak luminosity of 1.3x1034 cm-2 s-1 SATIF-13 12/10/2016 E. Skordis

particle tracklength fraction (14 TeV CM) HL-LHC DESIGN: CODE INTERCOMPARISON particle tracklength fraction in the Nb3Sn coils [%] photons 88 electrons/positrons 7 neutrons 4 pions 0.45 protons 0.15 Instantaneous luminosity: 5 1034 cm-2 s-1 Integrated luminosity: 3000 fb-1 [MARS calculations by N. Mokhov and his team, FNAL] SATIF-13 12/10/2016 E. Skordis

shielding extension (Inermet, 7cm) BPM shielding (Inermet, 18cm) WP10 team triplet interconnect optimization to address the Q2b weak point 36 MGy after 3ab-1 shielding extension (Inermet, 7cm) BPM shielding (Inermet, 18cm) 36 MGy -15% -15% significant benefit from crossing plane swap (hor <–> ver), since the regular inversion of the crossing angle – which pays in the LHC – is applicable only for vertical crossing SATIF-13 12/10/2016 E. Skordis

Beam losses during ion runs in the LHC - Mostly Pb-Pb (2015) - General ion run losses are very different from protons - Pb-Pb runs also have intrinsic beam losses around the collision points ATLAS, ALICE, CMS, LHCb (IP1, IP2, IP5, IP8) Superconducting dipole magnets (MBs) BFPP losses deposit energy in several LHC superconducting dipoles Bound- Free Pair Production (BFPP) is the main contribution to fast Pb-Pb beam burn-­off SATIF-13 12/10/2016 E. Skordis

Beam losses during ion runs in the LHC Peak power density for HL-LHC: Linst=6 x 1027cm-2s-1 7 Z TeV BFPP Quench Test BLM comparison Beam 2 Beam 2 SATIF-13 12/10/2016 E. Skordis

Intercepting BFPP losses with collimator SATIF-13 12/10/2016 E. Skordis

Conclusions FLUKA is the standart tool at CERN for shielding design and collimator upgrades for future LHC operation at higher intensity and luminosity Complex beam line models of the insertion regions and dispersion suppressors have been implemented, covering hundreds of meters of beam line The simulations are essential to relate key quantities (peak dose/peak power inside magnet coils) to measurements (dosimeters/BLMs next to magnets) Excellent BLM signal reproduction demonstrates the reliability of the simulation models for different loss scenarios Thank you! SATIF-13 12/10/2016 E. Skordis

BACK UP SLIDES SATIF-13 12/10/2016 E. Skordis

LHC collimation system Capable of redirecting up to 500kW of proton loss rate in order to protect the Super Conducting Magnets from quenching (stop being SC due to energy deposition -> increase in temperature) The majority of that power is deposited in the whole IR7 and IR3 Not all power is absorbed by the collimators themselves R. Bruce, 2014.09.15 500 kW Beam loss SATIF-13 12/10/2016 E. Skordis

IR7 DS Peak power deposition in the SC coils SATIF-13 12/10/2016 E. Skordis

IR7 DS Peak power deposition in the SC coils Main Dipoles Main Quadrupoles 13.4 mW/cm3 Beam 2 4 mW/cm3 SATIF-13 12/10/2016 E. Skordis

Magnet coils peak power deposition (radial average) Present layout 1 DS collimators Main Dipoles Main Quadrupoles 3 mW/cm3 2.6 mW/cm3 Beam 2 SATIF-13 12/10/2016 E. Skordis

LHC BLM System What does BLM System stand for? Beam Loss Monitoring System What is it? Consists of various detectors (active dosimeters), mainly; Ionisation Chambers (IC) Little IC Secondary Emission Monitors (SEM) in development… Each detector has different response times and detection range Each detector serves a different role What is its purpose? To measure beam losses around the accelerator and protect the machine from various beam loss scenarios SATIF-13 12/10/2016 E. Skordis