Outlook

1. Expected damage on TCTA collimator during HRMT09-LCOL experiment in HiRadMat facilityCollimation Working Group30.7.2012F. CarraA. Bertarelli, A. Dallocchio, L. Lari, N. Mariani Federico Carra – EN-MME

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

3. Scope of the studypresented • Three different testson 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-InducedDamage: Reckless or tooCautious?“,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 Federico Carra – EN-MME

4. Equivalentdamage: 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! Federico Carra – EN-MME

5. FEA: 3D Model +/-10 mm through 5th axis Stiffener (Glidcopmodeled 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) Federico Carra – EN-MME

6. Damageclassification Three different damage scenarios, with increasing severity, were identified: Jaw Damaged Area (red) Level 1 : H ≤ 8 mmLevel 2: H > 8 mm • 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 ...) Federico Carra – EN-MME

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

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

9. Test 1: equivalent SPS bunches • 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 jawvs.Damage on cooling pipes: which one to use as a reference? Federico Carra – EN-MME

10. Test 2: beamparameters • 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 Federico Carra – EN-MME

11. 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 Federico Carra – EN-MME

12. Test 3: beamparameters • 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 • LHC 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 ??? • Preliminary estimation with FLUKA: 50 SPS bunches to have an equivalent energy peak Energy peak in the axial coordinate, courtesy of L. Lari Federico Carra – EN-MME

13. Test 3: expecteddamageprovoked 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 Federico Carra – EN-MME

14. Test 3: equivalent SPS bunches • ~ 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 ) Federico Carra – EN-MME

15. 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. Federico Carra – EN-MME