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

0.7sec.

beam50 GeV PSH
adron

Single turn fast extraction
8 bunches in 5µs
3.3x1014proton/spill
Cycle: 3.53 sec.

Neutrino beam line

Neutrino beam lineline

Hadron & Neutrino beam linesHadron beam lineTime(sec.)

Slow extraction: 0.7 sec.

Windows in hadron beam line
50GeV PS：10-8 Torr
Fast reaction valve

10-6~10-8 Torr
Turbo &Ion pumpContainer of T1-target(air and water inside)
10-3 Torr
Rotary pump

Beam dump(Low Pressure?)

NP-hall

Switch Yard

SY Vacuum window

Window forT1-upstream

Vacuum chamber :20cm-φ, SS or Al or Ti
Connected by ‘Radial seal’

Window for
T1-downstream
Window for Dump

SY vacuum window•Separate vacuum in SY(10-3Torr) from one in 50GeV-PS (10-8Torr)•Aluminum : 20cm-φ, 100µm-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

Deposit(W/m3)
Deposit (W/m3)

1.2E+07
1.0E+078.0E+06

σr ~ 1cm

6.0E+06
4.0E+06
2.0E+06
0.0E+00
0246R (cm)Radius(cm)

810+16(K)Time dependence of temperature
Temperature(ºC)

Aluminum

Stainless SteelCenter46

Temperature(ºC)

300Center3030060

Time(sec)

T>1 min. ： T=30 +16 ± 4 (ºC)

060

Time(sec)

T>20 min. ： T = 30 + 480 ± 10 (ºC)

Beam window for T1-target
T1 container

SS/Al

T1 target

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

AirVacuumchamber~10-3 Torr
SS/AlSSSS

Beam axis

Primary beam line:~10-3 Torr
He1g/cm2
1m/s

Upstream windows for T1
diameter:10cm

HeWater

Downstream
windows for T1
diameter:30cm

Upstream window for T1 (T1-U)•Separate vacuum of beam line (10-3Torr) 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=100µm)
SS window

Thicknesst (cm)(cm)

Deposit(W/m(W/m3) 3)
Deposit

5.0E+08
4.0E+08

σr ~ 2mm

3.0E+082.0E+08
1.0E+08
0.0E+00
0123

RadiusR (cm)(cm)

45

0.30
0.25
0.20
0.15
0.10
0.05
0.00

2.5mm

100µm
0123R (cm)Radius(cm)

45

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/m2/K
Forced convection : 100W/m2/K
SS window+320(K)Temperature rise : 320 (K)SS window+160(K)

Temperature rise : 160 (K)Deformation/Stress of window T1-U
SS window

SS window

0.7mm

Deformation:0.7mm@centerMax. stress due to pressure：
200MPa@center＜Tensile strength:500MPa

If t=0.1mm(uniform)•deformation：2.1mm•Stress：310MPa@center,1000MPa@edge

Helium cooling at KEK-B factory
Double wall ofBeryllium~100W heat
Vacuum chamber
for interaction point

Aluminum Beryllium

He WatercooledHeliumcooledAluminum

Water
cooledHe

Heat transfer coefficient
1g/s (6l/s, 1.7m/s)•120W/m2K(measured by U.Tsukuba)•164W/m2K(calculation)•220W/m2K(measured by IHI)

Helium cooling systemwater cooler

He tank

He compressor

He coolerwater pumpDownstream window for T1(T1-D)

2.5E+08

0.60

SS window

Thicknesst (cm) (cm)Deposit (W/m3)
Energy deposit(W/m3)•Separate vacuum chamber (10-3Torr) 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)

2.0E+08

σr ~ 5mm

1.5E+08
1.0E+08
5.0E+07
0.0E+00

5mm

0.50
0.40
0.30
0.20
0.10

100µm

0.00

0510R (cm) (cm)Radius150510R (cm)(cm)Radius15

Temperature/stress of window T1-D
SS window

SS window+170(K)

3.3mm

Outer edge: cooled to be 80ºC
Temperature rise:

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

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

Window for beam dump
•Separate vacuum in beam line (10-3Torr) 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)
Thickness (cm)1.40E+06

6.00E-01

1.20E+06

5.00E-01

1.00E+06

σr ~ 5cm

8.00E+055mm

4.00E-01t (cm)Deposit (W/m3)

Energy deposit on window (W/m3)

6.00E+05

3.00E-01
2.00E-01

1mm

4.00E+051.00E-01

2.00E+05

0.00E+00

0.00E+00
051015R (cm)2025

Radius (cm)051015R (cm)2025

Radius (cm)Temperature/stress of window(dump)
SS window

SS window

Outer edge: cooled to be 30ºC
Temperature rise:

Deformation:5.7mm
Stress due to pressure:
200MPa at R=20cm<Tensile strength 500MPa+8(K)8(K) @100W/m2K
64(K) @10W/m2K

Windows in neutrino beam line
PQ1

PQ2B

50GeV PSPH3
PQ5 PV2

サブ トンネ

PQ4B

PQ4A

PV1

PQ3B

PQ3A

PQ2A

PD1
1.92 deg. bend

PH2

PH1

PD21.92 deg. bend

Preparation Section

ルA

PS vacuum window (?)
サブ トンネルB

ARC Section(Super conducting)

サブトンネルD

サブ

トンネ•Separate vacuum in PS&ARC&FF(10-6Torr)from one in 50GeV-PS (10-8Torr)
Target Station

Cル

Final Focusing
SectionHeliumcontainer
Final focus

TS exit window(?)

放射化物保管室

Decay volume(Helium)

Target Station
60.0

TS entrance window

Window in Preparation Section3)
Deposit(W/m(W/m3)
Deposit•Separate vacuum in PS(10-6Torr) from one in 50GeV-PS (10-8Torr)•20cm-φ, Al 26µm-t(?) or SS 10µm-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 26µm-t
5.0E+07
Al 26µm-t

4.0E+073.0E+072.0E+07σr ~ 6mm (smallest case)

1.0E+07
0.0E+00
024Radius (cm)R (cm)

6810+14(K)Window for entrance of TSDeposit(W/m(W/m3) 3)Deposit•Separate vacuum in PS(10-6Torr) 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?
6.0E+07
Al 1mm-t
Al 1mm-t
5.0E+07
4.0E+073.0E+07σr ~ 6mm

2.0E+07
1.0E+07
0.0E+00
00.5

11.5Radius(cm)R (cm)

22.5+18(K)Summary•We started to study on windows for 50GeV beam line.
•Average temperature rise and deformation/stress bypressure 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(E0)50 GeV リング

30m
h03
h01 v02

q01
S1

SY Vacuum window

v04 q03

q02
S2h07
q04

S3

SM1

S4

q05
S5v06

h05

q06 q07

S7

S6

q09 q0A

q12 h13v08

q08

S8

q11

S9

S10

S11S13

S12

Fast reaction valve
MP10-6~10-8 Torr
Turbo & Ion pump (every 20m)

一次ビームライン-3 Torr
10（Aライン）Rotary pump (every 20m)

SM1T0

ゲートバルブビームモニターラジアルシール
ビーム膜

q11

q12 h13q13

q14v14q15

q16 h16h15

q17 q18 v17

真空ポンプ
S13

S14

q19 q1A

S15
S16

Vacuum chamber :20cm-φ, SS or Al or Ti
Connected by ‘Radial seal’

S17

S18

S19

S20

S21

S22

S23

Hadron beam line in NP-Hall
Container of T1-target(air and water inside)
10-3 Torr

Beam dump(Low Pressure?)

10-3 Torr
S23

S24

S25
S26

Q19

Q1AQ1B

第１コリメータ

Q1C

Q1D

第２コリメータWindow for
T1-downstream

Window forT1-upstream

ゲートバルブビームモニターラジアルシール
ビーム膜

10m

Window for Dump

真空ポンプ

２００３．３．４改訂

Neutrino target station
22m

33m
40t crane
11m
Ground level
Concrete blocks

Service pit
Machineroom
Heliumcontainer
Iron shield

Finalfocus

Iron shieldBeamwindow
Decay
volumeBeam window
Concrete
Stock room for
Baffleactivated parts
Target & 1st horn 2nd horn 3rd horn

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 work
should be done at service space
1. Disconnect cables andcooling tubes.
2. Detach vacuum flanges.
3. Replace shields with cask.
4. Detach shaft, disks andupper plate, andmove them to stock space.
5. Install new parts with cask.
6. Replace cask with shields.
7. Connect cables and tubes.

water3m

requires remote maintenance toolsmotorshieldbeam
targetbeam
Front view

Side viewRemote vacuum sealing
Design specification•Inner Diameter: ≥30cm•Metal sealing•Small leak:~1×10-10 Pa•m3/s•Remote operation•Operation time: 1~5 min.
•Small force requiredCandidate•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
Specificationzzzzzz

Up to 40t
Short height
Remote connection
Video camera viewing
Two or four points liftingInterlock for one-side lifting

Crane

MagnetUnder design
Lifting tools fromCERN and PSINeutrino beam line
Beam Decay Target Fast-extracted proton
dump volume station beam line
SuperKamiokandeνµ beam of ~1GeVzνµ→ νx disappearancezνµ→ νe appearance

50GeV PS

Target and secondary beam lines
Production target : T1
Rotating Nickel disks•thickness: ~54 mm•radius: ~24 cm•cooled by water•developed by Y.Yamanoi
et. al.
ProtonbeamHR

K1.8

K1.1

NP-HallK0