1. First international Design Review of the MYRRHA accelerator. Spoke Cryomodule Design Bruxelles- 12/13 November 2012 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

2. 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

3. 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 - OK Mechanical design - in-work (close to completion) Cavity Helium tank - only conceptual  Preliminary design of Cryostat Conceptual design fixed Cryogenic design fixed (in collaboration with ACS Task 4_2) Preliminary Overall sizing – OK Providing 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

4. General Specifications and Overview MAX T3_3 = Detailed design of the Spoke CM for End 2013 Two Cells Spoke Cavity @ 352.2 MHz,  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

5. 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

6. SPOKE CAVITY (2/4) Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012 GOALS Epk/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 parameter Optimized RF parameters Optimal beta0.37 Vo.T [MV/m] @ 1 Joule & optimal beta0.693 Epk/Ea4.29 Bpk/Ea [mT/MV/m]7.32 G [Ohm]109 r/Q [Ohm]217 Qo @ 2K for Rres=20 nΩ5.2 E+09 Pcav for Qo=2 E+09 & 6.4 MV/m [W]9.35 Lacc=0.315m=optimal beta x c x f

7. SPOKE CAVITY (3/4) Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012 Epk Bpk Lcav=435mm Next steps: - Qext calculation - Lorentz forces detuning factor - Mechanical optimization

8. 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 Stifness5000 N/mm25 Mpa for 1 mm elongation Buckling Critical Pressure2.5 barsSpecification : P max inside helium Tank = 1.5 bars Mechanical Eigen mode60 HzFirst 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

9. POWER COUPLEUR (1/2) WARM WINDOW A Power Coupler 350 MHz, 20 kW CW (designed), 50 . 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

10. 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 Same Area

11. 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

12. Magnetic Shielding No 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

13. 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

14. 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.

15. 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

16. Cryostat Design / Assembly - Cryostating Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012

17. Cryostat Design / Cryogenic Loops Internal CM circuiteryQT max  Int & L t CD  P max 40/80 K Loop Cool Down (Ghe 4/3 bars)2g/sNC10 mm, 15 m9 hr115 mbar 40/80 K Loop Stationary (Ghe 4/3 bars)110 W86,2 K10 mm, 15 mNC4 mbar  5/10 K Loop (Lhe 3/1 bar)15 W10 KNC1 mbar  Mag. Shield Cool Down (LHe 1,2/1 bar)10 mm, 8 m0.3 hr180 mbar  Cavity Cool Down (Lhe 1,2/1 bar)1,2 hr  Cavity Stationary30 W<10 -1 mbar    Spoke Cryomodule Design - H. SAUGNAC - First international Design Review of the MYRRHA accelerator- Bxl 12/13 November 2012

18. Cryostat Design / Pressure Security Accident : Insulation Vacuum breakage. Volume LHe ~ 100 litres Surface He loop ~ 2,6 m 2 q = 6 kW/m 2 (CERN, Conservative) m’= 742 g/s T fluid out < 20 K P 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

19. Cryostat Design / Thermo-Mechanical Evaluations Conservative (To Be optimized)Q* 300K  70K Q 70K  2K Q 70K  10K Q 10K  2K Cavity frame- Solid Conduction (With 5K/10K Heat Sink) 22,6 WNC1,6 W0.11 W Power Coupler - Solid Conduction 30 WNC6 W< 0.1 W Beam Tube solid conduction (300K  2K Transition) 1,6 W0,1 WNC Burst disk pipe Solid Conduction (to be evaluated) < 2 W< 0.1 W Thermal radiation (30 layers MLI @60K ; 10 layers MLI @2K ) 30W (6W/m 2 ) 0.2 W (0,06 W/m 2 ) NC Thermal radiation (Beam tubes, measurement chimney) 2,74 W0.1 WNC Thermal radiation Power Couplers (to be evaluated) < 5W ???< 2W ?? Instrumentation, Wiring (to be evaluated) < 5 W< 0.5 W Cavity Frame (To be Optimized)  X  Y*  Z*  V.M. @ 300K (100 Kg/Cavity)-0,1/+0,14-0,9/+0,9-0,6/+078 MPa @ Cold ( 100 Kg/Cavity + thermal contraction)-3,6/+0,2-0,5/+0,5-2/+078 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

20. 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

21. 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.