Vacuum windows at JPARC

Contents•Introduction•Vacuum windows at hadron beam line

Helium gas cooling•Vacuum windows at neutrino beam line

primitive discussion

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

Hadron & Neutrino beam lines

Neu

trino b

eam lin

e

Had

ron

beam

line

50 GeV PS

Neutrino beam lineSingle turn fast extraction8 bunches in 5s3.3x1014proton/spillCycle: 3.53 sec.

Hadron beam lineSlow extraction: 0.7 sec.Time(sec.)

0.7sec.

Windows in hadron beam line

Fast reaction valve

SY Vacuum window

10-6~10-8 TorrTurbo & Ion pump

10-3 TorrRotary pump

50GeV PS： 10-8 Torr

Vacuum chamber :20cm-, SS or Al or TiConnected by ‘Radial seal’

Window for T1-upstream

Window for T1-downstream

Window for Dump

Container of T1-target(air and water inside)

Beam dump(Low Pressure?)

NP-hall

Switch Yard

SY vacuum window

0.0E+00

2.0E+06

4.0E+06

6.0E+06

8.0E+06

1.0E+07

1.2E+07

0 2 4 6 8 10R (cm)

Dep

osi

t (W

/m3

)

•Separate vacuum in SY(10-3Torr) from one in 50GeV-PS (10-8Torr) •Aluminum : 20cm-, 100m-t•Edge : cooled at 30ºC by water or air•Average deposit: 3.5J/spill Temperature rise : 16(K) (SS: 480(K) )

(MARS+ANSYS)

Radius (cm)

Dep

osit

(W

/m3 )

r ~ 1cm

Aluminum window

+16(K)

Time dependence of temperature

Aluminum Stainless Steel

T>1 min. ： T=30 +16 ± 4 (ºC) T>20 min. ： T = 30 + 480 ± 10 (ºC)

Time(sec) Time(sec)

CenterCenter

Tem

per

atu

re(º

C)

600 600

30

46

30

300

Tem

per

atu

re(º

C)

Beam window for T1-target

Water

Air

Primary beam line:~10-3 Torr

Vacuum chamber

~10-3 Torr

Upstream windows for T1 diameter:10cm

Downstream windows for T1 diameter:30cm

He1g/cm2

1m/s

He

T1 target

Double wall (SS or Al)•cooled by He flow in gap•gap: ~1cm•remote maintenance

Beam axisSS

SSSS/Al

SS/Al

T1 container

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 1 2 3 4 5R (cm)

t (c

m)

Upstream window for T1 (T1-U)

0.0E+00

1.0E+08

2.0E+08

3.0E+08

4.0E+08

5.0E+08

0 1 2 3 4 5R (cm)

Dep

osit

(W/m

3)

•Separate vacuum of beam line (10-3Torr) from air(1atm) in T1 container•SS/Al (beam-line side) and SS (T1 side) : 10cm-, 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=100m)

Radius (cm)

Dep

osit

(W

/m3 )

r ~ 2mm

Radius (cm)

Th

ick

nes

s (c

m)

100m

2.5mmSS window

Temperature of window T1-U

Temperature rise : 320 (K)

Natural convection : 10W/m2/K

Temperature rise : 160 (K)

Forced convection : 100W/m2/K

Outer edge : cooled to be 30ºC by water or airOne surface : cooled by convection by Helium

SS window SS window

+160(K)+320(K)

Deformation/Stress of window T1-U

Deformation:0.7mm@center Max. stress due to pressure ：200MPa@center＜ Tensile strength:500MPaIf t=0.1mm(uniform)

•deformation ： 2.1mm•Stress ： 310MPa@center,1000MPa@edge

SS window SS window

0.7mm

Helium cooling at KEK-B factory

He

He

Heat transfer coefficient

1g/s (6l/s, 1.7m/s)•120W/m2K(measured by U.Tsukuba)

•164W/m2K(calculation)

•220W/m2K(measured by IHI)

Watercooled

Helium cooled

Aluminum AluminumBeryllium

Double wall of Beryllium

Watercooled

Vacuum chamberfor interaction point

~100W heat

Helium cooling system

He compressor He coolerHe tank water pump

water cooler

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0 5 10 15R (cm)

t (c

m)

Downstream window for T1(T1-D)

0.0E+00

5.0E+07

1.0E+08

1.5E+08

2.0E+08

2.5E+08

0 5 10 15R (cm)

Dep

osit

(W/m

3)

•Separate vacuum chamber (10-3Torr) from air(1atm) in T1 container•SS/Al (beam-line side) and SS (T1 side) : 30cm-, 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)

r ~ 5mm

100m

5mm

Radius (cm)

En

ergy

dep

osit

(W

/m3 )

Th

ick

nes

s (c

m)SS window

Radius (cm)

Temperature/stress of window T1-D

Outer edge: cooled to be 80ºCTemperature rise:

170(K) @100W/m2K810(K) @10W/m2K

Deformation:3.3mmStress due to pressure:450MPa at center~Tensile strength 500MPa

SS window SS window

+170(K) 3.3mm

Window for beam dump

0.00E+00

2.00E+05

4.00E+05

6.00E+05

8.00E+05

1.00E+06

1.20E+06

1.40E+06

0 5 10 15 20 25

R (cm)

Depo

sit

(W/m

3)

0.00E+00

1.00E-01

2.00E-01

3.00E-01

4.00E-01

5.00E-01

6.00E-01

0 5 10 15 20 25

R (cm)

t (c

m)

•Separate vacuum in beam line (10-3Torr) from air in beam dump•Stainless Steel : 50cm-, variable thickness•Simple wall or double wall with Helium cooling•Average deposit: 136 J/spill (98 J/spill if thickness is 1mm-t)

Radius (cm) Radius (cm)

Energy deposit on window (W/m3)

r ~ 5cm

Thickness (cm)

1mm

5mm

Temperature/stress of window(dump)

Outer edge: cooled to be 30ºCTemperature rise:

8(K) @100W/m2K64(K) @10W/m2K

Deformation:5.7mmStress due to pressure:200MPa at R=20cm<Tensile strength 500MPa

SS window SS window

+8(K)

Preparation Section

ARC Section(Super conducting)

Final Focusing Section

Windows in neutrino beam line

Target Station

PS vacuum window (?)

•Separate vacuum in PS&ARC&FF(10-6Torr)

from one in 50GeV-PS (10-8Torr)

50GeV PS

TS exit window(?)

TS entrance window

Final focus

Decay volume (Helium)

Helium container

Target Station

0.0E+00

1.0E+07

2.0E+07

3.0E+07

4.0E+07

5.0E+07

0 2 4 6 8 10R (cm)

Dep

osi

t (W

/m3

)

r ~ 6mm (smallest case)

Window in Preparation Section

•Separate vacuum in PS(10-6Torr) from one in 50GeV-PS (10-8Torr) •20cm- Al 26m-t(?) or SS 10m-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 26m-t

Radius (cm)

Dep

osit

(W

/m3 )

Al 26m-t

+14(K)

0.0E+00

1.0E+07

2.0E+07

3.0E+07

4.0E+07

5.0E+07

6.0E+07

0 0.5 1 1.5 2 2.5

R (cm)

Dep

osi

t (W

/m3

)

r ~ 6mm

Window for entrance of TS

•Separate vacuum in PS(10-6Torr) from He gas (1 atm) in TS •Aluminum : 5cm-、 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-tAl 1mm-t

Radius (cm)

Dep

osit

(W

/m3 )

+18(K)

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

He gasDouble wall

‘Radial seal flange’

Backup

Hadron beam line in Switch-Yard

Fast reaction valve

SY Vacuum window

10-6~10-8 TorrTurbo & Ion pump (every 20m)

10-3 TorrRotary pump (every 20m)

50GeV PS： 10-8 Torr

30m

Vacuum chamber :20cm-, SS or Al or TiConnected by ‘Radial seal’

ゲートバルブビームモニターラジアルシールビーム膜

真空ポンプ

Q19 Q1A

Q1B Q1C Q1D

第２コリメータ第１コリメータ

２００３．３．４改訂

S23 S24 S25

S26

Hadron beam line in NP-Hall

Window for T1-upstream

Window for T1-downstream

Window for Dump

10-3 Torr10-3 Torr

Container of T1-target(air and water inside)

10m

Beam dump(Low Pressure?)

22m

Neutrino target station

Iron shield

Helium container

Machine room

Service pit

Stock room for activated parts

11m

33m

Iron shield

Concrete blocks

40t crane

Target & 1st horn

Beam window

2nd horn 3rd horn

Final focus

Decay volume

Concrete

Beam window

Ground level

Baffle

T1 downstream window

•Diameter: ~30cm

•Vacuum side: Aluminum

•Air(T1) side: SS

•0.1mm-t at center

•5mm-t at edge (water cooled)

•Temperature rise of SS window at center

+170ºC (forced convection by He flow(~1m/s) : 100W/m2K)+810ºC (natural convection : 10W/m2K)

Remote maintenance for T1

Maintenance workshould be done at service space

1. Disconnect cables and cooling tubes.

2. Detach vacuum flanges.3. Replace shields with cask.4. Detach shaft, disks and

upper plate, andmove them to stock space.

5. Install new parts with cask.6. Replace cask with shields.7. Connect cables and tubes.

requires remote maintenance tools

shield

motorwater

beam target

beam

Front view Side view

3m

Remote vacuum sealing

Design specification•Inner Diameter: 30cm•Metal sealing•Small leak:~110-10 Pa•m3/s•Remote operation

•Operation time: 1~5 min.•Small force required

Candidate•Mechanical holding (V-block)•Pillow seal•Radial seal (under development)

Prototype of “Radial seal”developed by Y.Yamanoi(KEK) ,M.Tsuchiya(IHI Ltd) andUsui Kokusai Sangyou Kaisya Ltd.

Remote lifting Tools

Lifting tools from CERN and PSI

Magnet

Crane

SpecificationUp to 40tShort heightRemote connectionVideo camera viewingTwo or four points liftingInterlock for one-side lifting

Under design

Neutrino beam line

νμ beam of ~1GeV

Target station

Decay volume

Beamdump

Fast-extracted proton beam line

50GeV PSSuper-Kamiokande

→ x disappearance→ e appearance

Target and secondary beam lines

K1.8

HR

K1.1 K0

Production target : T1 Rotating Nickel disks

•thickness: ~54 mm •radius: ~24 cm•cooled by water•developed by Y.Yamanoi

et. al.

Proton beam NP-Hall