Damage Levels - Comparison of Experiment and Simulation V. Kain AB/Co

1. Damage Levels - Comparison of Experiment and SimulationV. Kain AB/Co • Contents … • Introduction • Assumed damage levels – TT40 accident • Controlled damage test • FLUKA results • Comparison with experiment • Conclusion • Scope … • Comparison of predicted damage limits with experiment • Damage limits for the LHC will not be defined Verena Kain, AB-CO

2. Introduction The damage limit of equipment has to be known for … • design of machine protection procedures • design of protection elements (robustness,…) • settings of protection systems • thresholds of monitoring systems (BLMs,…) • “safe” beam condition • design of operational procedures • … Knowledge on damage levels based on simulations… • especially for LHC energies and intensities • mostly static energy deposition calculated (FLUKA,…) • dynamic effects (shock waves,…)? • simulation vs. experiment? • simulation vs. experiment! ~25cm long hole in chamber of QTRF in TT40. Both Chamber and magnet had to be exchanged. 10 cm Inside, damage visible over ~1m (melted steel) Verena Kain, AB-CO

3. Assumed damage levels • 450 GeV • ~ 2x1012 protons ≈ 5% of full ultimate batch • 7 TeV • ~1010 protons Damage limit at 450 GeV: 1 full nominal batch » damage limit 25th of October: MSE trip during high intensity extraction. Damage of QTRF pipe and magnet. ~25cm long hole in chamber 10 cm Verena Kain, AB-CO

4. Reconstitution of Scenario and Comparison with Simulation • Analysis of logging data: • MSE tripped due to EMC of LHC beam 11ms before extraction • in 11ms field changes by 5% • number of extracted protons: 3.4x1013@450GeV Reconstructed trajectory according to screen shots. Input for FLUKA simulation (x, x’). The energy deposition result is very sensitive to accurate input parameters. Difficult to reproduce the observed damage. The melting point of 314L: 1400°C. Slit due to heat + stress, rather than melting? max. Temp. 1350°C Meaningful comparison with simulation: CONTROLLED EXPERIMENT stainless steel: 314L Verena Kain, AB-CO

5. 108 plates 30 cm 6 cm 6 cm Controlled Damage Test • Low-tech target, no extra instrumentation (no temperature sensors,…) • Simple target geometry: • Stack of high-Z metal plates • 4 predefined 450GeV- beam intensities (A, B, C, D) • Intensities chosen to see certain effect on plate: melting/not melting Double Confinement Screen Motor Verena Kain, AB-CO

6. Target Description • Materials: • Zn, Cu, Stainless Steel (316L, INCONEL) • Special order of materials: • packages of 3 materials • Zn, Cu, 316L (INCONEL), Zn, Cu, 316L (INCONEL),… • plates 6cm x 6cm x 2mm • place-holders between plates (0.5mm) → avoiding molten plates sticking together FLUKA model of target geometry Every plate has unique longitudinal position: → number on each plate → 3D experiment: longitudinal position + damaged area on plate Verena Kain, AB-CO

7. FLUKA Results… plate 11 plate 15 Heat of fusion not taken into account… Cu Predicted observations… Results taking heat of fusion into account… ¼ of a nominal batch Verena Kain, AB-CO

8. Damage test in TT40 • Target was installed in TT40 in front of TED in air. • Target irradiation: 8th of November. • 4 shots: intensities A, B, C, D TED – TT40 Screen Ti entrance window • Opened box: 5th of January → no full analysis yet! • Took pictures of some plates (will take pictures of ALL plates) Verena Kain, AB-CO

9. Results … Observations when we opened the box… • outer confinement: no damage • first plates no damage as expected • after 6 packages more and more damage • no stress related damage (buckling, twisting, cracks, …), mostly very clean results… Verena Kain, AB-CO

10. Results… beam direction Only in this part shows melting … Verena Kain, AB-CO

11. Results… Plate 1, Zn Impact locations for the different intensities… A B D C ☼☼☼☼ Verena Kain, AB-CO

12. Results… Plate 7, Zn Marks of melting for intensity D… Prediction: melting @ D A B D C Verena Kain, AB-CO

13. Results… Plate 8, Zn Marks of melting for intensity D only… Prediction: melting @ D A B D C Verena Kain, AB-CO

14. Results… Plate 9, Zn Marks of melting for intensity D & C Prediction: melting @ D & C A B D C Verena Kain, AB-CO

15. Results… Plate 20, Zn Melting for intensity D & C & B A B D C Verena Kain, AB-CO

16. Results… Plate 10, Cu Marks of heating for intensity D Prediction: no melting A B D C Verena Kain, AB-CO

17. Results… Plate 12, Cu Marks of melting for intensity D Prediction: melting @ D A B D C Verena Kain, AB-CO

18. Results… Plate 17, Cu Marks of melting for intensity D & C Prediction: melting @ D (plate nr. 18: melting @ D & C) A B D C Verena Kain, AB-CO

19. Results… Plate 36, Cu Melting for intensity D & C Marks of heating for intensity B A B D C Verena Kain, AB-CO

20. Results… • None of the stainless steel plates shows holes. • INCONEL: as predicted • 316L: predicted melting from plate 23… not observed. • Needs further investigation… Verena Kain, AB-CO

21. Conclusions • First examinations show good agreement with simulations • Zn, Cu, INCONEL as predicted • 316L still unclear • Melting as predicted by FLUKA • transverse size of damage still to be checked • Gives confidence that damage limits could be adequately simulated… • geometry has large effect • sensitive to details of beam impact • full modelling on case-by-case basis is essential • no simple scaling • Establishing generic damage limits seems to be difficult… Verena Kain, AB-CO

22. Thanks to … K. Vorderwinkler, J. Ramillon, F. Loprete, G. Ferioli, R. Schmidt, B.Goddard, J. Lettry, F. Decorvet, J. Vo Duy, R. Harrison, W. Weterings, S. Sgobba, S. Calatroni, A. Dorsival, H. Vincke, M. Mueller, D. Forkel-Wirth, A. Desirelli Verena Kain, AB-CO