Material transition from He Vessel K.Saito KEK

Material Transition Location Transition @ He vessel base plate a) Nb/Ti (EBW) Ti vessel No transition till the end of gas return pipe b) Nb/Ti (EBW) Ti vessel Ti/SUS @ somewhere (maybe LHe inlet) SUS pipe c) Nb/SUS (HIP) SUS Vessel SUS pipe

Japanese High Pressure Regulation Issues Comment Ti Vessel and No transition Nb cavity High cost due to Ti material Ti vessel Ti Bellows Life ? LHe supply Ti pipe Nb/Ti joint @ LHe vessel base plate Gasket sealing b) Ti Vessel and transition @ LHe inlet c) SUS Vessel Low cost due to SUS material Nb/SUS joint @ LHe vessel base plate Thermal stress SUS Bellows

Mechanical property @ cold temperatures Materials 0.2% Yield Strength [MPa] 300K 77K 4.2K Tensile [MPa] 300K 77K 4.2K Charpy Impact Test [J] 300K 77K 4.2K Nb 34.3 ~51.0 621.7 ±47.7 132.4 ~154.5 930.0 ±48.0 1st Grade 2nd Grade Tsuchiya 204.3 ±4.2 346.3 ±5.5 408.3 ± 13.8 297.7 ±6.0 715.7 ±4.2 951.7 ±9.0 261.8 ± 4.6 213.8 ±16.2 195.8 ± 12.7 351.7 ±7.0 636.0 ±4.6 691.3 ±16.6 445.7 ±7.1 863.7 ±3.1 1093 ±5.3 101.0 ± 8.1 32.0 ± 2.5 27.8 ± 4.5 114.6 ±6.9 88.3 ±75.8 SUS 316L 615.6 ±2.3 1483.6 ±5.0 Ti(2nd)/Ti (2nd) TIG welding 274.7 ±21.5 443.3 ±22.0 517.7 ±17.8 415.3 ±2.1 822.0 ±2.6 1041.7 ±3.1 50.6 ±0 38.4 ±2.0 34.8 ±1.0 EBW 334.0 ±1.7 573.3 ±1.2 649.3 ±9.6 447.7 ±0.6 859.7 ±2.1 1088.0 ±3.5 59.6 ±1.5 55.7 ±0 52.8 ±1.3 Nb/Ti(2nd) EBW 61.6 ±4.4 18.2 ±3.8 19.5 ±7.9 Nb/Cu/SUS 316L HIP 276.4 ±8.4 694.4 ±28.9 Nb/Ti HIP ND 183.8 ±63.1 Ti/SUS 316L HIP Tsuchiya (several conditions) Tsuchiya (STF) 475.4 ±44.3 381 ~ 486 566 ~ 742 3.2 ~ 10.1 1.1 ~ 4.3 746 ±55.2 10.4 ±2.1 4.2 ±0.5 Ti/Ni/SUS 316L Explosive Bonding 358.4 ±45.2 537.8 ±31.5 25.3 ±1.4 20.0 ±1.3 Ti/SUS 316L Friction & Compensation 778.3 ±55.2 2.9 1.7 Ti Charpy impact energy must be higher than 18-27 J/cm2 @ 2K by Japanese high pressure vessel cord.

Thermal stress at the base plate By H.Yamaoka High Mn steel D Ti Ti SUS316L Ｃ B A Nb Nb Cu Nb Nb/Ti+SUS316L Nb/Ti+High Mn steel Nb/Cu/SUS316L Thermal expansion coefficient Maximum Surface Stress [E-6/K] SUS316L 16.0 Cu 17.0 High Mn steel 9.8 Ti 8.4 Nb 5.0 A [MPa] B C D Nb/Cu/SUS316L 250 500 Nb/Ti/SUS316L 100 200 470 Nb/Ti/High Mn Steel 80

Nb/SUS end plate design @ KEK He tank: SUS316L TIG welding High Mn Steel or SUS SUS EBW Nb EBW

R&D for the Transition Joint Proposal R&D for the Transition Joint Develop transition joint method with a high sharpy value at cryogenic Temp. Test the pulsed shock behavior at cryogenic Temp. Investigate Bellows life for the pulse operation