Vacuum windows at JPARC Yoshikazu Yamada (KEK) T.Ishii, T.Iwashita, - PowerPoint PPT Presentation

Vacuum windows at JPARC Yoshikazu Yamada (KEK) T.Ishii, T.Iwashita, M.Minakawa, Y.Oyama, H.Takahashi, et.al. 4th International Workshop on the Neutrino Beams and Instrumentation November 10, 2003 Contents • Introduction • Vacuum windows at hadron beam line Helium gas cooling • Vacuum windows at neutrino beam line primitive discussion

Hadron & Neutrino beam lines Neutrino beam line Neutrino beam line Single turn fast extraction Hadron beam line 8 bunches in 5 µ s 3.3x10 14 proton/spill Cycle: 3.53 sec. 50 GeV PS 0.7sec. Hadron beam line Slow extraction: 0.7 sec. Time(sec.)

Windows in hadron beam line Beam dump 50GeV PS ： (Low Pressure?) 10 -8 Torr Container of T1-target (air and water inside) 10 -3 Torr Fast reaction valve NP-hall Rotary pump 10 -6 ~10 -8 Torr Switch Yard Turbo & Ion pump Window for Window for SY Vacuum window T1-upstream T1-downstream Vacuum chamber :20cm- φ , SS or Al or Ti Window for Dump Connected by ‘Radial seal’

SY vacuum window • Separate vacuum in SY(10 -3 Torr) from one in 50GeV-PS (10 -8 Torr) • Aluminum : 20cm- φ , 100 µ m-t • Edge : cooled at 30ºC by water or air • Average deposit: 3.5J/spill ⇒ Temperature rise : 16(K) (SS: 480(K) ) (MARS+ANSYS) Aluminum window 1.2E+07 Deposit (W/m 3 ) 1.0E+07 Deposit (W/m3) 8.0E+06 σ r ~ 1cm 6.0E+06 4.0E+06 2.0E+06 0.0E+00 +16(K) 0 2 4 6 8 10 Radius (cm) R (cm)

Time dependence of temperature Aluminum Stainless Steel Temperature(ºC) 300 Temperature(ºC) Center Center 46 30 30 0 60 0 60 Time(sec) Time(sec) T>1 min. ： T>20 min. ： T = 30 + 480 ± 10 (ºC) T=30 +16 ± 4 (ºC)

Beam window for T1-target T1 container Double wall (SS or Al) Vacuum T1 target He • cooled by He flow in gap chamber Air ~10 -3 Torr • gap: ~1cm SS/Al • remote maintenance SS SS SS/Al Beam axis Primary beam line:~10 -3 Torr He 1g/cm 2 Downstream 1m/s windows for T1 Upstream windows for T1 Water diameter:30cm diameter:10cm

Upstream window for T1 (T1-U) • Separate vacuum of beam line (10 -3 Torr) from air(1atm) in T1 container • SS/Al (beam-line side) and SS (T1 side) : 10cm- φ , variable thickness • Cooled by He(1atm & 1m/s) between two walls • Average deposit:10.2 J/spill on SS window (9.2 J/spill if t=100 µ m) 5.0E+08 0.30 SS window 2.5mm Deposit (W/m 3 ) 0.25 Thickness (cm) 4.0E+08 Deposit (W/m3) 0.20 σ r ~ 2mm 3.0E+08 t (cm) 0.15 2.0E+08 0.10 100 µ m 1.0E+08 0.05 0.00 0.0E+00 0 1 2 3 4 5 0 1 2 3 4 5 Radius (cm) Radius (cm) R (cm) R (cm)

Temperature of window T1-U Outer edge : cooled to be 30ºC by water or air One surface : cooled by convection by Helium Natural convection : 10W/m 2 /K Forced convection : 100W/m 2 /K SS window SS window +320(K) +160(K) Temperature rise : 320 (K) Temperature rise : 160 (K)

Deformation/Stress of window T1-U SS window SS window 0.7mm Max. stress due to pressure ： Deformation:0.7mm@center 200MPa@center If t=0.1mm(uniform) ＜ Tensile strength:500MPa • deformation ： 2.1mm • Stress ： 310MPa@center,1000MPa@edge

Helium cooling at KEK-B factory Double wall of Beryllium ~100W heat Vacuum chamber He for interaction point Beryllium Aluminum Aluminum Heat transfer coefficient 1g/s (6 l /s, 1.7m/s) • 120W/m 2 K(measured by U.Tsukuba) Helium Water Water He • 164W/m 2 K(calculation) cooled cooled cooled • 220W/m 2 K(measured by IHI)

Helium cooling system water cooler He tank He compressor He cooler water pump

Downstream window for T1(T1-D) • Separate vacuum chamber (10 -3 Torr) from air(1atm) in T1 container • SS/Al (beam-line side) and SS (T1 side) : 30cm- φ , variable thickness • Cooled by He(1atm & 1m/s) between two walls • Average deposit: 1060 J/spill on SS window (115 J/spill if t=0.1mm) 0.60 Energy deposit (W/m 3 ) 2.5E+08 SS window 5mm 0.50 Thickness (cm) 2.0E+08 Deposit (W/m3) 0.40 σ r ~ 5mm 1.5E+08 t (cm) 0.30 1.0E+08 0.20 100 µ m 5.0E+07 0.10 0.0E+00 0.00 0 5 10 15 0 5 10 15 Radius (cm) Radius (cm) R (cm) R (cm)

Temperature/stress of window T1-D SS window SS window 3.3mm +170(K) Outer edge: cooled to be 80ºC Deformation:3.3mm Temperature rise: Stress due to pressure: 450MPa at center 170(K) @100W/m 2 K ~Tensile strength 500MPa 810(K) @10W/m 2 K

Window for beam dump • Separate vacuum in beam line (10 -3 Torr) from air in beam dump • Stainless Steel : 50cm- φ , variable thickness • Simple wall or double wall with Helium cooling • Average deposit: 136 J/spill (98 J/spill if thickness is 1mm-t) Energy deposit on window (W/m 3 ) Thickness (cm) 1 . 4 0 E + 0 6 6 . 0 0 E - 0 1 5mm 1 . 2 0 E + 0 6 5 . 0 0 E - 0 1 1 . 0 0 E + 0 6 ) σ r ~ 5cm 3 4 . 0 0 E - 0 1 m / ) 8 . 0 0 E + 0 5 W m ( c 3 . 0 0 E - 0 1 ( t i t s 6 . 0 0 E + 0 5 o p e 2 . 0 0 E - 0 1 1mm D 4 . 0 0 E + 0 5 1 . 0 0 E - 0 1 2 . 0 0 E + 0 5 0 . 0 0 E + 0 0 0 . 0 0 E + 0 0 0 5 1 0 1 5 2 0 2 5 0 5 1 0 1 5 2 0 2 5 R ( c m ) R ( c m ) Radius (cm) Radius (cm)

Temperature/stress of window(dump) SS window SS window +8(K) Outer edge: cooled to be 30ºC Deformation:5.7mm Temperature rise: Stress due to pressure: 200MPa at R=20cm 8(K) @100W/m 2 K <Tensile strength 500MPa 64(K) @10W/m 2 K

Windows in neutrino beam line P Q 1 P Q 2 A P Q 2 B P D 1 P H 2 PH1 . 9 d 2 e g . b e n d PQ3A 1 PQ3B PD2 PV1 . 1 9 e 2 d b . g d e n PQ4A 50GeV PS PQ4B Preparation Section PH3 Q 5 P V 2 P ンネルA サブト PS vacuum window (?) ンネルB サブト • Separate vacuum in PS&ARC&FF(10 -6 Torr) ARC Section from one in 50GeV-PS (10 -8 Torr) (Super conducting) Target Station ンネルC サブト Helium Final Focusing container Section ンネルD Final focus TS exit window(?) サブト Decay volume 放 射 化 物 (Helium) 保 管 室 Target Station TS entrance window 6 0 . 0

Window in Preparation Section • Separate vacuum in PS(10 -6 Torr) from one in 50GeV-PS (10 -8 Torr) • 20cm- φ, Al 26 µ m-t(?) or SS 10 µ m-t(?) (0.01% loss) (realistic?) • Edge : cooled at 30ºC by water or air • Average deposit : 0.68J/spill ⇒ ∆ T : Al:~14(K), SS:~520(K) • But, ∆ T by single spill ⇒ Al:~67(K), SS:~104(K) • study on thermal stress and durability against heat cycle • study with larger beam size Al 26 µ m-t 5.0E+07 Al 26 µ m-t Deposit (W/m 3 ) 4.0E+07 Deposit (W/m3) 3.0E+07 2.0E+07 σ r ~ 6mm (smallest case) 1.0E+07 0.0E+00 +14(K) 0 2 4 6 8 10 Radius (cm) R (cm)

Window for entrance of TS • Separate vacuum in PS(10 -6 Torr) from He gas (1 atm) in TS • Aluminum : 5cm- φ 、 1mm-t (can be thinner) • Edge : cooled at 30ºC by water or air • Average deposit : 34J/spill ⇒ ∆ T ~18(K) • But, ∆ T by single spill ⇒ 82(K) • study on thermal stress and durability against heat cycle • double wall and Helium cooling? Al 1mm-t 6.0E+07 Al 1mm-t 5.0E+07 Deposit (W/m 3 ) Deposit (W/m3) 4.0E+07 3.0E+07 σ r ~ 6mm 2.0E+07 1.0E+07 0.0E+00 +18(K) 0 0.5 1 1.5 2 2.5 Radius (cm) R (cm)

Summary • We started to study on windows for 50GeV beam line. • Average temperature rise and deformation/stress by pressure were estimated by MARS+ANSYS • Conduction cooling for aluminum windows for • Switch Yard of hadron beam line • Preparation Section of neutrino beam line (?) • Forced convection cooling by helium gas for windows for • Upstream/downstream of T1 target in hadron beam line • Beam dump in hadron beam line • Entrance window of neutrino target station (?) • Exit window of neutrino target station (??)

Plan • Study of thermal stress and shock wave • Optimization of thickness • Measurement of thermal transfer coefficient of He cooling • Test production of windows and study durability • Design and production of double wall window with ‘Radial seal flange’ system developed by Y.Yamanoi et.al. Proton beam Double wall He gas ‘Radial seal flange’

Backup

Hadron beam line in Switch-Yard 50GeV PS ： 10 -8 Torr 仮想取り出し点( E 0 ) 5 0G e Vリング S M 1 30m SY Vacuum window h 0 3 v 0 4 q 0 3 q 0 9 q h 0 7 0 A q 1 1 q 1 2 h 1 3 h 0 1v 0 2 q 0 1 q 0 2 q 0 4 q 0 5 v 0 6 q 0 6 q 0 7 q 0 8 v 0 8 h 0 5 S 1 S 2 S 7 S 8 S 3 S 4 S 6 S 9 S 1 1 S 1 3 S 5 S 1 0 S 1 2 Fast reaction valve M P 10 -6 ~10 -8 Torr 10 -3 Torr 一次ビームラ イ ン （ A ラ イ ン） Turbo & Ion pump (every 20m) Rotary pump (every 20m) S M 1 T 0 ゲート バルブ ビームモニタ ー ラジアルシール v 1 4 q 1 6h 1 6 q 1 3 q 1 5 q 1 1 q 1 2 h 1 3 q 1 4 ビーム膜 h 1 5 q 1 7q 1 8v 1 7 q 1 9 q 1 A 真空ポン プ S 1 3 S 1 5 S 1 4 S 1 6 Vacuum chamber :20cm- φ , SS or Al or Ti S 2 2 S 2 3 S 1 7 S 1 8 S 1 9 S 2 1 S 2 0 Connected by ‘Radial seal’