HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

1KEK

Crab Cavities: Cryostat R&D
KEKB Crab Cavity GroupNAKAI Hirotaka

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK

2Overview• Design of Cryostat• Parts Fabrication Techniques R&D• Establishment of Assembly Site

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK3

Cryostat Design Constraints• Accommodation of Squashed-Cell CrabCavity• High Pressure Pure Water Rinsing (HPR)
Applicable When Cavity Degraded• Coaxial Coupler Movable for Tuning• Support & Cooling for Long CoaxialCoupler

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

4Cryostat Design Concept• Jacket-Type Liquid Helium (LHe) Vessel• Coaxial Coupler with Bellows• Stub Support for Long Coaxial Coupler• Jacket-Type Magnetic Shield around Cavity

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEKTop View

5

Cryostat Conceptual DesignInput coupler

Coaxial Couplerwith Bellows

Jacket-type LHe VesselRFAbsorber

BellowsI.D. 240

StubSupport

RFAbsorber

I.D.100

Coaxial Coupler

Monitor Port
Liq. He

Liq. He
80 K LN2 Radiation Shield

KEKB Review Committee/20040216

Crab Mode
Reject Filter

Stub Support

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

6Cryostat Design (Top View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK

7

Cryostat Design (Side View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK

8

Cryostat Design (Front View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK9Analyses of Cryostat Design• Thermal Analyses– Heat Leak to Cryostat– Heat Leak Through Tuner• Structure Analyses– Stress of Cryostat (End Shells, etc.)– Stress of Stub Support– and so on …

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

10Heat Leak Calculation(Top View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK11Heat Leak Calculation(Side View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK12Tuner and Heat Leak Calculation(Top View)

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

13Heat Leak to Cryostat

KEKHeat Leak [W]Heat Leak PathHeat Transfer Mode

Inner Conductor

To 80 K Region To 4 K Region
Stainless Steel Tube

––

1.8

Outer Conductor

Stainless Steel Tube
Copper Plating

24.2

5.4

0.8
1.1
1.5

Input Coupler

Outer Conductor

Stainless Steel Tube
Copper Plating

13.0
3.2

1.01.9Beam Pipes

Beam Pipes

Stainless Steel Tube
Copper Plating

41.2
6.9

1.9
1.9

Outer Sleeves (2 Sleeves)

1.4
3.4

0.1
0.3

Cavity Supports (4 Wires)

–0.6
–––

0.7
0.6

10.6
––
0.4

109.3

14.6

Coaxial Coupler

Conduction
TunerSupports

Copper Plating

Inner Rods (2 Rods)

80 K Shield Supports
LHe Transfer Tubes (2 Tubes)

Plumbing

Liquid Level Sensor Support
Safety Valve Plumbing

Wiring

Thermocouples, Cables, etc.
Vacuum Vessel to 80 K Shield

Radiation

80 K Shield to LHe Vessel

Total Amount of Heat LeakKEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK14

Parts Fabrication R&D• Seamless Copper Bellows for CoaxialCoupler• End Shells of Cryostat• Thin Pipes for Beam Pipes & InputCouplers

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK

15

Copper Bellows - Purposes• Coaxial Coupler
Connection toCavity• Tuning with Coaxial
Coupler Position

KEKB Review Committee/20040216

Pitch 17.9 mm

R = 3 mmt = 0.4 mm

I.D. 188 mm

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK16Copper Bellows - Seamless Pipes

Drawing Bench:
Capacity 30 tons
KEKB Review Committee/20040216

Fabricated 5-cell Bellows
NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEK17

End Shells - Dimensions• Vacuum Vessel– Diameter 1200, thickness 2• Liquid Helium Vessel– Diameter 600, thickness 1.5– Diameter 920, thickness 2

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATION

KEKEnd Shells

Vacuum Vessel End Shell

KEKB Review Committee/20040216

18Liquid Helium Vessel End Shells

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK19Thin Pipes - Dimensions• Input Coupler– Diameter 120, thickness 0.5• Beam Pipes– Diameter 188, thickness 0.8– Diameter 240, thickness 0.8

KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK20

Thin Pipes - Drawing Bench

Drawing Bench:
Capacity 100 tons
KEKB Review Committee/20040216

NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEKAssembly Site

Clean Room for Cavity andCryostat Assembly
KEKB Review Committee/20040216

21

Ultra Pure Water Plant for High
Pressure Pure Water Rinsing
NAKAI Hirotaka

HIGH ENERGY ACCELERATOR RESEARCHORGANIZATIONKEK22Summary• 1st Cryostat Construction in FY 2004
• Parts Fabrication R&D in Progress• Fabrication of Vacuum Vessel Started• Collaboration with Mechanical Engineering
Center of KEK

KEKB Review Committee/20040216

NAKAI Hirotaka