Federico Carra – EN-MME Expected damage on TCTA collimator during HRMT09-LCOL experiment in HiRadMat facility Collimation Working Group 30.7.2012 F. Carra A. Bertarelli, A. Dallocchio, L. Lari, N. Mariani 30.07.2012 Federico Carra – EN-MME

Federico Carra – EN-MME Outlook Scope of the study performed FEA 3D model Damage classification Accident simulation results Test 1 Test 2 Test 3 Conclusions 30.07.2012 Federico Carra – EN-MME

Scope of the study presented Three different tests on the TCTA will be performed in HiRadMat facility : Test 1: to reproduce LHC asynchronous dump (single bunch setup, 1 bunch at 7 TeV energy impacting tungsten jaw) Test 2: to assess the threshold damage on the collimator, in terms of beam energy and intensity (damage not imposing collimator replacement) Test 3: to reproduce a destructive scenario and benchmark simulations (“Limits for Beam-Induced Damage: Reckless or too Cautious?“, A. Bertarelli et al. , Chamonix 2011) How many SPS bunches (and at which intensity) are necessary to reproduce the 3 different scenarios, identified for the LHC? FLUKA simulations – L. Lari: Equivalence of the energy peak + Autodyn FEA – F. Carra: Equivalence of the damage produced on the jaw 30.07.2012 Federico Carra – EN-MME

Equivalent damage: LHC vs. SPS Preliminary analyses – FLUKA (L. Lari) Equivalence of the energy peak Equivalence of the maximum temperature (considering adiabatic conditions, constant specific heat) Input for successive Autodyn FEA Autodyn FEA Equivalence of the damage produced on the jaw Shockwave is propagating during the time between two successive bunches → pressure waves are not linearly superposing! 30.07.2012 Federico Carra – EN-MME

FEA: 3D Model +/-10 mm through 5th axis Material EOS Strength model Stiffener (Glidcop modeled as OFE-Cu) Water Screw (x40) (Stainless Steel) Block Support (OFE-Copper) Cooling Pipes (Cu(89%)-Ni(10%)-Fe(1%) modeled as OFE-Cu) Jaw block (x5) (W(95%)-Ni(3.5%)-Cu(1.5%) partly modelled as pure W) Material EOS Strength model Failure model Tungsten Tabular (SESAME) Johnson-Cook Plastic strain/ Hydro (Pmin) Copper OFE Polynomial Stainless steel AISI 316 Shock Plastic strain Water - Hydro (Pmin) 30.07.2012 Federico Carra – EN-MME

Damage classification Level 1 : H ≤ 8 mm Level 2: H > 8 mm Three different damage scenarios, with increasing severity, were identified: Level 1 (Collimator need not be replaced). Limited jaw damage, an intact spare surface can be found relying on the 5th axis movement (+/- 10 mm). (Provided this movement is possible). Permanent jaw deformation is limited. Level 2 (Collimator must be replaced). Damage to collimator jaw is incompatible with 5th axis travel (H > 8 mm). Other components may also be damaged (e.g. Screws). Level 3 (Long down time of the LHC). Catastrophic damage to collimator leading to water leakage into beam vacuum (pipe crushing, tank water circuit drilling ...) Jaw Damaged Area (red) Level 1 : H ≤ 8 mm Level 2: H > 8 mm 30.07.2012 Federico Carra – EN-MME

Test 1: beam parameters ??? LHC scenario SPS (HiRadMat) scenario 7 TeV 1 bunch 1,5E11 p/b σ = 0.5x0.5 mm2 Impact parameter (test): x = 2 mm y = 10 mm ??? SPS (HiRadMat) scenario 440 GeV X bunches 1,5E11 p/b σ = 0.5x0.5 mm2 Impact parameter: x = 2 mm y = 10 mm Bunch spacing: 50 ns Preliminary estimation with FLUKA: 20 SPS bunches to have an equivalent energy peak Energy peak in the axial coordinate, courtesy of L. Lari 30.07.2012 Federico Carra – EN-MME

Test 1: expected damage provoked by 1 LHC bunch, 7 TeV Tungsten damaged zone ~ 9 mm + plastic deformation of copper beam Maximum pl. strain on pipes ~ 2.1% 30.07.2012 Federico Carra – EN-MME 1 bunch, 7 TeV: cooling pipes

Test 1: equivalent SPS bunches Pulse characteristics Height of the damaged W surface [mm] 1 bunch, 7 TeV 9 16 bunches, 440 GeV 7.5 18 bunches, 440 GeV 8.4 20 bunches, 440 GeV 9.2 24 bunches, 440 GeV 10.5 30 bunches, 440 GeV 12.2 Pulse characteristics Max. plastic deformation on cooling pipes 1 bunch, 7 TeV 2.10% 16 bunches, 440 GeV 1.07% 18 bunches, 440 GeV 1.26% 20 bunches, 440 GeV 1.40% 24 bunches, 440 GeV 1.70% 30 bunches, 440 GeV 2.08% 20 SPS bunches are necessary to provoke the same damage which is expected for 1 LHC bunch on the tungsten jaw For an LHC equivalent damage on the cooling pipes, 30 SPS bunches are necessary! Scratch on the W jaw vs. Damage on cooling pipes: which one to use as a reference? 30.07.2012 Federico Carra – EN-MME

SPS (HiRadMat) scenario Inermet microstructure Test 2: beam parameters SPS (HiRadMat) scenario 440 GeV X bunches → X = max. n. SPS bunches for which 80% of W melting temperature is not exceeded (S. Redaelli) 1,5E11 p/b σ = 0.5x0.5 mm2 Impact parameter: x = 2 mm y = 10 mm Bunch spacing: 50 ns W grains Metallic matrix Inermet: Cu/Ni Densimet: Fe/Ni Inermet microstructure 30.07.2012 Federico Carra – EN-MME

6 bunches, 440 GeV – Temperature Test 2: results 6 bunches to stay below 80% of W melting temperature (unavoidable melting of Cu/Ni phase) No plastic strain of the tungsten active surface Scenario equivalent to 1 LHC bunch, 7 TeV, 4.5e10 p 6 bunches, 440 GeV – Temperature 30.07.2012 Federico Carra – EN-MME

Test 3: beam parameters ??? LHC scenario SPS (HiRadMat) scenario 5 TeV 4 bunches 1,3E11 p/b σ = 0.5x0.5 mm2 Impact parameter (test): x = 2 mm y = 10 mm Bunch spacing: 25 ns ??? SPS (HiRadMat) scenario 440 GeV X bunches 1,5E11 p/b σ = 0.5x0.5 mm2 Impact parameter: x = 2 mm y = 10 mm Bunch spacing: 50 ns Preliminary estimation with FLUKA: 50 SPS bunches to have an equivalent energy peak Energy peak in the axial coordinate, courtesy of L. Lari 30.07.2012 Federico Carra – EN-MME

Test 3: expected damage provoked by 4 LHC bunches, 5 TeV Coarser mesh to reduce calculation times Change of density between each of the last bunches is introducing an error > 10% Calculation will be refined in the next weeks Considerable vertical deformation of the copper beam Extensive damage on the tungsten jaw Plastic strain on cooling pipes ~ 10%! 4 bunches, 5 TeV: Vertical Displacement 30.07.2012 Federico Carra – EN-MME

Test 3: equivalent SPS bunches N. bunches Height of the damaged W surface [mm] 4 bunches, 5 TeV 19.2 40 bunches, 440 GeV 12.8 50 bunches, 440 GeV 15.4 60 bunches, 440 GeV 18 80 bunches, 440 GeV 23 N. bunches Max. plastic deformation on cooling pipes 4 bunches, 5 TeV 9.63% 40 bunches, 440 GeV 2.67% 50 bunches, 440 GeV 3.33% 60 bunches, 440 GeV 3.77% 80 bunches, 440 GeV 4.35% ~ 65 SPS bunches are necessary to provoke the same damage which is expected for 4 LHC bunch (5 TeV) on the tungsten jaw In the HiRadMat facility, an equivalent damage provoked on the cooling pipes by 4 LHC bunches (5 TeV) is not reproducible! (decreasing beam σ would have very limited effect ) 30.07.2012 Federico Carra – EN-MME

Conclusions Simulations were performed with FLUKA and Autodyn in order to evaluate the correct beam parameters for HRMT09 experience. Test 1: 20 bunches proposed for an equivalent damage on W jaw; 30 bunches to have the same pipes plastic deformation. What part of the jaw to be taken as a reference? Test 2: 6 bunches are proposed: Tmax < 0.8Tmelt(W), no plastic deformation of active jaw surface. Total beam intensity: 9e11 protons. Test 3: 65 bunches are proposed: damage on W jaw is equivalent to the destructive case that should be reproduced. With current HiRadMat parameters, high plastic strain levels on cooling pipes cannot be reached. TEST 1 N. bunches Pulse Intensity Damage extension on W jaw [mm] Pl. Strain on cooling pipes 1 bunches, 7 TeV 1.5e11 p 9 2.10% 20 bunches, 440 GeV 3e12 p 9.2  1.40%  30 bunches, 440 GeV 4.5e12 p 10.5  2.08%  TEST 3 N. bunches Pulse Intensity Damage extension on the W jaw [mm] Pl. Strain on cooling pipes 4 bunches, 5 TeV 5.2e11 p 19.2 9.63% 65 bunches, 440 GeV 9.75e12 p ~ 19  ~ 4% 30.07.2012 Federico Carra – EN-MME