Damage Levels V. 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 11/29/2018 Verena Kain, AB-CO

simulation vs. experiment! Introduction The damage limit of equipment is important input… design of operational procedures design of machine protection procedures design of protection elements (robustness,…) thresholds of monitoring systems (BLMs,…) “safe” beam condition … 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) 11/29/2018 Verena Kain, AB-CO

Assumed damage levels 450 GeV 7 TeV Damage limit at 450 GeV: ~ 2x1012 protons = 5% of full ultimate batch 7 TeV ~1010 protons Damage limit at 450 GeV: Check with reality: 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 Inside, damage visible over ~1m (melted steel) 11/29/2018 Verena Kain, AB-CO

Reconstitution of Scenario and Comparison with Simulation Analysis of post mortem 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. 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 11/29/2018 Verena Kain, AB-CO

Controlled Damage Test Low-tech target, no extra instrumentation (no temperature sensors,…) Simple target geometry: Stack of high-Z metal plates 4 predefined beam intensities (A, B, C, D) Intensities chosen to see certain effect on plate: melting/not melting 30 cm 108 plates 6 cm Double Confinement Screen Motor 11/29/2018 Verena Kain, AB-CO

Target Description Every plate has unique longitudinal position: 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 Every plate has unique longitudinal position: → number on each plate → 3D experiment: longitudinal position + damaged area on plate 11/29/2018 Verena Kain, AB-CO

Melting starting in plate (nr.) FLUKA Results… plate 11 plate 15 Cu Heat of fusion not taken into account… Intensity #bunches Melting starting in plate (nr.) Zn Cu 316L INCONEL A 12 - B 24 17 C 48 9 18 D 72 6 23 Results taking heat of fusion into account… ¼ of a nominal batch 11/29/2018 Verena Kain, AB-CO

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) 11/29/2018 Verena Kain, AB-CO

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, mostly very clean results… 11/29/2018 Verena Kain, AB-CO

Results… beam direction Only in this part shows melting … 11/29/2018 Verena Kain, AB-CO

Results… A B D C ☼ ☼ ☼ ☼ Plate 1, Zn Impact locations for the different intensities… A B D C ☼ ☼ ☼ ☼ 11/29/2018 Verena Kain, AB-CO

Results… Plate 7, Zn Marks of melting for intensity D… Prediction: Nr. 6 11/29/2018 Verena Kain, AB-CO

Results… Plate 8, Zn Marks of melting for intensity D only… Prediction for intensity C: Nr. 9 11/29/2018 Verena Kain, AB-CO

Results… Plate 9, Zn Marks of melting for intensity D & C Prediction: Nr. 9 11/29/2018 Verena Kain, AB-CO

Results… Plate 20, Zn Marks of melting for intensity D & C & B 11/29/2018 Verena Kain, AB-CO

Results… Plate 10, Cu Marks of heating for intensity D Prediction of melting point: Nr. 11 11/29/2018 Verena Kain, AB-CO

Results… Plate 12, Cu Marks of melting for intensity D Prediction: Nr. 12 11/29/2018 Verena Kain, AB-CO

Results… Plate 17, Cu Marks of melting for intensity D & C Prediction: Nr. 18 11/29/2018 Verena Kain, AB-CO

Results… Plate 36, Cu Marks of melting for intensity D & C Marks of heating For intensity B 11/29/2018 Verena Kain, AB-CO

Results… None of the stainless steel plates shows holes. INCONEL: as predicted 316L: predicted melting from plate 23 Needs further investigation… 11/29/2018 Verena Kain, AB-CO

Conclusions First examinations show good agreement with simulations Zn, Cu, INCONEL as predicted 316L still unclear Melting as predicted by FLUKA ± ~ 20% uncertainties on beam size 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 11/29/2018 Verena Kain, AB-CO

Thanks to … K. Vorderwinkler, J. Ramillon, F. Loprete, B.Goddard, J. Lettry, F. Decorvet, J. Vo Duy, R. Harrison, W. Wetterings, S. Sgobba, S. Calatroni, A. Dorsival, R. Schmidt, H. Vincke, M. Mueller, D. Forkel-Wirth, A. Desirelli 11/29/2018 Verena Kain, AB-CO