Dump Core Studied Design Solutions Francois-Xavier Nuiry Giulia Romagnoli Tobias Polzin Edouard Grenier Boley With the support of EN-MME

Design Driving Parameters Parameters to consider in the core housing design: Project constraints Material sandwich selected in FEM simulations Cooling need Vacuum requirements Geometrical constraints Minimize weight Radiations Fatigue Ti6Al4V housing 14 Ti6Al4V blocks 6 NiCr blocks BEAM 3 solutions proposed keeping the same core sandwich geometry: Tube soldered on housing surface Boite a eau with drilled channels in housing 3D printing solution 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review Proposed Designs BRAZED TUBES DRILLED CHANNELS (Boite a Eau) 3D PRINTING 6 seamless cooling circuits brazed to housing Ti tubes to avoid brazing problems due to CTE mismatches Square tubes to improve the brazing thermal conductivity Ti housing for mechanical assembly of blocks 9 channels gun-drilled inside Ti housing Vacuum compatibility to be checked Good thermal contact (only 1 brazing) Ti caps EBW to close the cooling circuit 15 parallel channels 3D printed with housing Cooling circuit efficiency high (1 brazing joint) Seamless circuit inside vacuum Ti housing with minimized thickness 12/10/2016 PS Internal Dump Core Review

VSC Group Requirements Summary of vacuum specifications EDMS 1221536: Materials selected to be agreed with VSC Welding: 100% penetration Pressure test with 100% helium at P ≥ water pressure No grinding or mechanical abrasions Room temperature leak rate > 2 x 10-11 Pa m3 s-1 is unacceptable All surface should be cleaned and degreased according to CERN EDMS document 347564 PS DUMP Project: Maximum outgassing level: not defined No need of bake-out (?) Pressure test (with 100% helium at P ≥ water pressure) Leak test VDAM meeting with VSC on the 21st Sep 2016 12/10/2016 PS Internal Dump Core Review

Ti Housing to Blocks Connection Foreseen connecting method: Vacuum brazing of the blocks to the housing Design developed together with EN-MME-FW Single Ti block Grooves on circular surface to insert the brazing wire Pocket on the side to guarantee the 1 mm gap for mechanical deformation Degassing hole for pumping in vacuum Degassing holes not aligned in beam axis! First brazing test on going… Brazing procedure validation in the following weeks! CDD numbers: PS_TDIL_0009 PS_TDIL_0010 12/10/2016 PS Internal Dump Core Review

Baseline Design of Ti Housing Design aspects common to the 3 design solutions: Ti housing open at the bottom to reduce mass and avoid beam interactions No water channels in the lower dump region to avoid beam interactions 2 Ti wings to equilibrate the weight and cover beam area during ralentisseur mode Accidental beam (5 1013 protons) 1 pulse ΔT in the water: 100-120 °C Half-model used in thermal simulation presented afterwards 6 NiCr blocks 14 Ti6Al4V blocks Depending on the design proposed the Ti housing can be: active (part of the cooling system) passive (acting just as mechanical assembly) 12/10/2016 PS Internal Dump Core Review

1st Design: Tube Soldered on Housing 6 seamless cooling circuits to be soldered to the Ti6Al4V housing: Parallel circuits to improve the cooling efficiency Ti tubes to avoid brazing problems due to CTE mismatches Square tubes to improve the brazing thermal conductivity Ti housing passive used for mechanical assembly of blocks Light assembly (4.1 kg) Design based on the collimators cooling design Standard solution for the vacuum acceptance No water to vacuum connections inside vacuum Cooling circuit efficiency reduced (2 brazing joints) Ti housing with minimized thickness 12/10/2016 PS Internal Dump Core Review

Tube Design Detailed Design 6 parallel channels (4 mm Ø, 500 mm long) 2.1 mm minimum wall thickness No connection in vacuum Total length of each cooling circuit ~1500 mm Longueur « cooling pipe 1 » : 1322mm Longueur « cooling pipe 2 » : 1454mm Longueur « cooling pipe 3 » : 1548mm Longueur « cooling pipe 4 » : 1426mm Longueur « cooling pipe 5 » : 1464mm Longueur « cooling pipe 6 » : 1488mm Design on going… 12/10/2016 PS Internal Dump Core Review

Tube Design Thermal Simulation 6 tubes: (7x7 mm with Ø 4 mm, 500 mm long) Brazing joint between tube and housing Brazing joint between blocks and housing No degassing holes and wire grooves ANSYS MODEL for Thermal Simulations 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review 2nd Design: Boite a Eau Boite a eau: 9 channels gun drilled inside the Ti housing Parallel channels for cooling efficiency Ti wings welded + Ti caps to close the cooling circuit Stainless steel shaft soldered to housing Vacuum compatibility to be validated and discussed Good thermal contact (only 1 brazing) Ti housing active (cooling inside) Simpler mechanical design Heavier assembly (5.8 kg) Design based on the Slit Assembly for Linac 4 Stainless steel shaft Ti housing with embedded cooling circuit Ti cap to close the cooling circuit Ti6Al4V blocks Rene 41 (NiCr) blocks Ti wing to cover the beam area 12/10/2016 PS Internal Dump Core Review

Boite a Eau Detailed Design EBW cap to housing Brazing of Ti to block Brazing of SS shaft to housing Design on going… Design details under discussion… 12/10/2016 PS Internal Dump Core Review

Boite a Eau Design Thermal Simulation Model used in thermal simulations: 9 parallel channels (5 mm Ø, 500 mm long) 2.5 mm minimum wall thickness ANSYS MODEL for Thermal Simulations Half-model used in thermal simulation presented afterwards 12/10/2016 PS Internal Dump Core Review

3rd Design: 3D Printing 15 parallel Ti channels 3D printed with the housing: Parallel circuits to improve the cooling efficiency Cooling circuit efficiency high (1 brazing joint) Ti housing active (cooling inside) Seamless circuit inside vacuum Ti housing with minimized thickness Ti wings in the center of the dump Central blocks in traditional machined materials Light assembly (4 kg) Design challenges: Material porosity Wall thickness between cooling channels and vacuum Mechanical fatigue Thermal fatigue Water erosion Particle damage fatigue Dynamical response of the target Test pieces produced to validate the design Cut in half for 3D printing machine size NO welds in cooling circuit! 12/10/2016 PS Internal Dump Core Review

3D Printing Design Thermal Simulation Model used in thermal simulations: 15 parallel channels (5 mm Ø, 500 mm long) 2.3 mm minimum wall thickness ANSYS MODEL for Thermal Simulations Half-model used in thermal simulation presented afterwards 12/10/2016 PS Internal Dump Core Review

Need of Cooling System ACCIDENTAL SCENARIO Protons 26 GeV 5 1013 σ = 1.8x4.7 mm Pulse time 2.1 µs Pulse period 2.4 s 3 pulses SFTPRO BEAM Protons 14 GeV 2 1013 σ = 2x3.7 mm Pulse time 2.1 µs Pulse period 1.2 s 2 pulses then cooldown time of 15 s LHC 25ns BEAM Protons 26 GeV 2.3 1013 σ = 1x4.7 mm Pulse time 2.1 µs Pulse period 3.6 s 5 pulses then cooling down time of 20 s Beam scenarios considered during simulations T amb Time T T max Cooling Time T start Example of SFTPRO beam temperature profile Not in scale T start = T amb ideal configuration Cooling system necessary? 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review Steady State LHC 25ns BEAM after 5 pulses and 20 s of cooling down time Tmax=84°C Tmax >> Tinitial COOLING NECESSARY! simulations to check the steady state temperature TSS with a defined cooling system Time T Steady state temperature X time T amb TSS < critical temperature for material Temperature distribution in the material at the SS + some cycles to check: stress in steady state << critical stress for the material 12/10/2016 PS Internal Dump Core Review

Preliminary Thermal Analysis Thermal simulations assumptions: LHC25 ns beam scenario considered for thermal simulations Symmetrical half model Convection coefficient in the water tubes of 6000 W/m2C  analytical calculations done with conservative mass flow Thermal conductance of brazed joints 1000 W/m2C  conservative value STEADY STATE thermal simulation: power distributed over the cycle time (38 s) TRANSIENT ANALYSIS up to 1 h to check max temperature Study the cycle averaged temperature increase during 1 h dumping Intensity Real intensity deposed during beam impact Averaged intensity deposition used in steady state simulations 5 Pulses Cooling Time 20 s Time LHC25ns Cyles 38 sec 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review Thermal Simulations BRAZED TUBES DRILLED CHANNELS (Boite a Eau) 3D PRINTING Steady State Tmax: 496 °C Steady State Tmax: 315 °C Steady State Tmax: 300 °C PRELIMINARY RESULTS 3D printing and boite a eau more efficient then tube solution For boite a eau and 3D printing the max temperature is reached after 12 min 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review 3 Designs Pros and Cons BRAZED TUBES DRILLED CHANNELS (Boite a Eau) 3D PRINTING Cooling circuit efficiency high (1 brazing joint) Seamless circuit inside vacuum Ti housing with minimized thickness Light assembly (11.6 kg) To be checked: Material porosity Wall thickness leak tightness Mechanical fatigue Thermal fatigue Water erosion Particle damage fatigue Standard for the vacuum acceptance Seamless circuits inside vacuum Ti housing minimized thickness Light assembly (11.7 kg) Complex mechanical assembly Cooling circuit efficiency reduced (two brazing joints) Good thermal contact (only 1 brazing) Simple mechanical design EBW in vacuum Heavier assembly (13.4 kg) Ti housing bigger 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review Conclusions 3 solutions proposed for the PS dump housing design The final design is not selected yet, further tests are needed: Thermal and mechanical analysis for maximum temperature and stress evaluation Cooling system detailed design 3D printing investigation tests Design requirements fulfillment 12/10/2016 PS Internal Dump Core Review

PS Internal Dump Core Review Thank you! 12/10/2016 PS Internal Dump Core Review