first international design review of the myrrha accelerator. spoke cryomodule design
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First international Design Review of the
MYRRHA accelerator.Spoke Cryomodule Design
Bruxelles- 12/13 November 2012
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
SUMMARY
Introduction
General Specifications and Overview. Spoke Cavity Design. Power Coupler Design Cold Tuning System Design Magnetic Shielding Design Cryostat Design
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
INTRODUCTION
The main objectives for the first Mid-Period were :
Preliminary design of auxiliary components
Power Coupler- OK (Optimization remains)CTS OK - (Optimization remains)Magnetic Shield - Only conceptual
Preliminary design of spoke Cavity :
RF design - OKMechanical design - in-work (close to completion)Cavity Helium tank - only conceptual
Preliminary design of Cryostat
Conceptual design fixedCryogenic design fixed (in collaboration with ACS Task 4_2)Preliminary Overall sizing – OKProviding a first CAD model of the complete Cryomodule -OK
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
General Specifications and OverviewMAX T3_3 = Detailed design of the Spoke CM for End 2013
• Two Cells Spoke Cavity @ 352.2 MHz, b geom = 0.35
• T Op = 2 K, P mean loss RF = 10 W• P max RF losses fault tolerance ~ 17 W• E acc max nominal = 6,2 MV/m• E acc max fault tolerance = 8,2 MV/m• 2 Cavities per CM
• P Load = 2 to 16 KW CW . • P nominal max = 8 KW • P max fault tolerance = 16 KW
• No Focusing components inside CM• P Loss Static = 5W/m @ 2K• P max cavity helium tank = 1.5 bar• P design cavity helium tank = 2 bar
Spoke Section Reference pattern
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
SPOKE BAR GEOMETRY : feedback from the two Single-Spoke resonators and Triple-Spoke resonator fabrication (EURISOL)
Base (H field area): • no racetrack shape 3D weld seams are not easy (Spoke
bar-to-cavity body connection) • no cylindrical shape Hpk too high
Conical shape is chosen
Center (E field area): racetrack shape is ok
SPOKE CAVITY (1/4)
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
SPOKE CAVITY (2/4)
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
GOALSEpk/Eacc < 4.4
Bpk/Eacc (mT/MV/m) < 8.3
• CST MicroWave Studio 2012• Model created with the 3D CAD
tools of MWS• Symetries: ¼, BC: Magnetic planes,
Tetrahedral mesh, Nb tetrahedrons~10 000
• 1st mode calculated (TM010)• Optimisation of a dozen parameterOptimized RF parameters
Optimal beta 0.37Vo.T [MV/m] @ 1 Joule & optimal beta 0.693
Epk/Ea 4.29Bpk/Ea [mT/MV/m] 7.32G [Ohm] 109r/Q [Ohm] 217
Qo @ 2K for Rres=20 nΩ 5.2 E+09
Pcav for Qo=2 E+09 & 6.4 MV/m [W] 9.35
Lacc=0.315m=optimal beta x c x f
SPOKE CAVITY (3/4)
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Epk
BpkLcav=435mm
Next steps:- Qext calculation- Lorentz forces detuning
factor- Mechanical optimization
SPOKE CAVITY (4/4)Preliminary mechanical FE simulations (ANSYS) have been performed on Model 0. Tenue to Vacuum (1 bar) 50 Mpa (V.M) With Donut stiffener
Mechanical longitudinal Stifness 5000 N/mm 25 Mpa for 1 mm elongation
Buckling Critical Pressure 2.5 bars Specification :P max inside helium Tank = 1.5 bars
Mechanical Eigen mode 60 Hz First mode with non global deformation RF frequency shift. (Without Donut Stiffener)
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
POWER COUPLEUR (1/2)A Power Coupler 350 MHz, 20 kW CW (designed), 50 W. WARM WINDOW
Was manufactured, in the framework of Eurotrans and successfully tested at 8 kW (amplifier limitation) CW on a 350 MHz, beta 0.15 Spoke cavity in a Cryomodule configuration.
Basis for design
2 CF16 ports for vacuum measurements.
1 port for electron emission measurement pick up
1 water cooling loop
Plain Copper Antenna
CF 63 on cavity
Thermal interception at 70 K (~15 W solid conduction) and ~ 10 K (~3 W solid conduction)
The Design (SNS Type) will be kept as if for MAX
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
POWER COUPLEUR (2/2)A conservative outer conductor lenght of 300 mm was taken to start the cryomodule design. Detailed simulations, for the thermal aspects remain to be done.A passive barometric compensation system (ESS Type) was studied in order to balance the atmospheric pressure force between the Coupler and the cavity train.
Vacuum vessel assembly flange
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
350 MHz Coax line
Warm Window block
Fixation rods to vacuum vessel fixed point)
Fixation rods to coupler (mooving point)
Barometric compensation bellow
Thermal contraction bellow
80 K Thermal interception
5/10 K Thermal interception
Sam
e A
rea
Cold Tuning System
One CTS was designed and tested on a Beta = 0.15, 350 MHz Spoke cavity in the framework of Eurotrans. The main parameters ( Cavity RF frequency sensitivity, Stiffness, Helium Tank relevant dimensions…) are similar with the MAX Spoke cavity. This design is taken for the Spoke MAX CTS Design. In addition an optimized design, in term of stiffness, is under study on a similar CTS for ESS 350 MHz Spoke cavities.
CTS (CEA ‘Soleil’ Type) for Eurotrans 350 MHz Spoke cavity
General studies on reliability (C&C, reliability of stepping motor and reductor) are conducted in the frame of the MAX Task T3_1.
The CTS detailed Design will be achieved once the Cavity Helium Tank is completed..
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Magnetic ShieldingNo detailled study is done yet on the Magnetic Shielding. No simulation on the magnetic field effect and the sizing of the Shield.As conceptual design we assume that the Magnectic Shield is : - Made of Cryoperm- Cooled down actively- Composed of two skins
Cavity Cool Down Phase
During Cool down phase the Cryoperm is first cooled and reach the optimal temperature (below 70 K) before the cavity becomes SC. In Stationary operation the shield only attached to the cavity helium tank reach an equilibrium temperature.Assemblies of the different parts of the shield are made with screws Requires long cooling tube ~ 8 m per cavity.This concept was succefully tested on SPIRAL2 CM B.
A more practical concept as trapping the cryoperm inside the Helium Tank may be considered….
SPIRAL 2 Concept
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cryostat Design / Overview
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Warm valve (No Cold Valves)
Adjustable supporting posts
Power couplers
Cavity train supporting frame
Cryogenic line connection
Level measurement and relief valves circuit chimney
2 K phase separator reservoir
Cold Tuning System
Actively cooled down magnetic shield
Barometric compensation
5/10K heat interception loop
Copper thermal shield (40/80K 4/3 bars)
Sliding and adjustable fixture to cavity train supporting frame (TTF Type)
Cavity pumping port
Coaxial 350 MHz Line
Cryostat Design / Overview
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Diagnostics box position and size ?.Longitudinal gain of space is still possible.
Cryostat Design / Assembly – Cold Mass
Inside Clean Room (Iso 4) Outside Clean Room
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cavity + Coupler, first assembled on Clean Room trolley.
Different components assembled on the CM suporting frame.
This frame goes outside and inside Clean room
Cryostat Design / Assembly - Cryostating
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cryostat Design / Cryogenic Loops
Internal CM circuitery Q T max F Int & L t CD DP max
40/80 K Loop Cool Down (Ghe 4/3 bars) 2g/s NC 10 mm, 15 m 9 hr 115 mbar
40/80 K Loop Stationary (Ghe 4/3 bars) 110 W 86,2 K 10 mm, 15 m NC 4 mbar
5/10 K Loop (Lhe 3/1 bar) 15 W 10 K NC 1 mbar
Mag. Shield Cool Down (LHe 1,2/1 bar) 10 mm, 8 m 0.3 hr 180 mbar
Cavity Cool Down (Lhe 1,2/1 bar) 1,2 hr
Cavity Stationary 30 W <10-1 mbar
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cryostat Design / Pressure Security
Accident : Insulation Vacuum breakage. Volume LHe ~ 100 litresSurface He loop ~ 2,6 m2
q = 6 kW/m2 (CERN, Conservative) m’= 742 g/sT fluid out < 20 KP cav max =1.5 bar
1 x Burst Disk (K=0.6, F = 60 mm) P discharge = 1.33 bar+/- 10%m’ max = 750 g/s @ T > 20 K
2 x Relief Valve (Circle seal type 500 F 1 ‘’) P oppening = 1.15 bar+/- 5%m’ max (each)= 120 g/s @ T = 20 K.Prevent overpressure from Cool Down operation, Quench…without breaking the Burst Disk…
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cryostat Design / Thermo-Mechanical Evaluations
Conservative (To Be optimized) Q* 300K70K Q 70K2K Q 70K10K Q 10K2K
Cavity frame- Solid Conduction (With 5K/10K Heat Sink) 22,6 W NC 1,6 W 0.11 W
Power Coupler - Solid Conduction 30 W NC 6 W < 0.1 W
Beam Tube solid conduction (300K2K Transition) 1,6 W 0,1 W NC NC
Burst disk pipe Solid Conduction (to be evaluated) < 2 W < 0.1 W
Thermal radiation (30 layers MLI @60K ; 10 layers MLI @2K ) 30 W(6W/m2)
0.2 W (0,06 W/m2)
NC NC
Thermal radiation (Beam tubes, measurement chimney) 2,74 W 0.1 W NC NC
Thermal radiation Power Couplers (to be evaluated) < 5W ??? < 2W ?? < 2W ??
Instrumentation, Wiring (to be evaluated) < 5 W < 0.5 W
Cavity Frame (To be Optimized) D X D Y* D Z* s V.M.
@ 300K (100 Kg/Cavity) -0,1/+0,14 -0,9/+0,9 -0,6/+0 78 MPa
@ Cold ( 100 Kg/Cavity + thermal contraction) -3,6/+0,2 -0,5/+0,5 -2/+0 78 MPa
*Require Optimizations Q 70 K < 100 W To be reduced, Q 5K/10K < 10 W, Q 2K < 3,2 W
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Cryostat Design / Accelerator Hall Cross section
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Valve box not designed yet. Can be optimized to gain space (parallepipedic instead of cylinder).Height of the hall remains to be checked taking into account handling (tools, strategy…) of the different components.
The vertical position of the LINAC depend on other components as elliptical cavity CM. Diameter, coupler lenght and Coupler doorknob and wave guides are in a first approximation compatible with a 1,5 m beam axis height.
700 MHz Elliptical cavity DoorKnob
Preliminary LINAC Tunnel Dimensions
RF amplifiers, electronic…Hall
Conclusions
Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012
Conceptual and preliminary designs achieved for the main components.
Cavity RF optimization achieved, mechanical optimisation in-work
Components (CTS, Coupler, Cryostat…)optimization to be achieved in June 2013
CAD detailed design & assembly tooling from June 2013.
A Spoke cavity prototype without helium tank is planed to be manufactured (order before end 2012…). Cryogenic tests will be performed in 2013 in order to validate the RF Design and the Manufacturing process.
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