1. outline Configurations overview (Tom) Detailed designs
Bathtub type: (top loading/intermediate temp. cavity support)
Gas return pipe: LCLS-II/XFEL (side loaded cryomodule / cold cavity support)
Strong back PIP-II (side loaded cryomodule / warm cavity support)
Comparison table
Detailed designs
PIP-II details (Tom)
SNS design (Ed) (side loaded cryomodule / warm cavity support)
ESS design (side loaded cryomodule / warm cavity support)
IFMIF design (side loaded cryomodule / cold cavity support)
DONES improvement based on Ifmif design (top loading)
SARAF design (top loading)

2. Cryomodule design: side / bottom / top loading
IFMIF LIPAc: side loading
FRIB: bottom loading
ANL: top loading
Triumf – Isac II:
top loading
PXIE HWR
Cryomodule
CERN
HIE Isolde:
top loading
ATLAS Upgrade
Top loading configuration more usual for low beta cavities
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 2

3. Ed Daly February 7, 2019 On behalf of JLab Team
SNS Space Frame Design
Ed Daly
February 7, 2019
On behalf of JLab Team

4. Introduction – Space Frame
~1999 – For Jlab Upgrade Cryomodules, Mark Wiseman thought of applying the space frame concept used in the aerospace industry
Space frame is a fixture that supports the cold mass components in-situ and facilitates cryomodule assembly steps
Needed a method to support 8-cavity string having no intercavity bellows
As C100 design was developed by Eric Feldl, the space frame design was integrated as part of the internal assembly
In 2000, SNS design followed this design concept
Test frame surrounding space shuttle during assembly
C100 Cut-away View Space frame supports internal components
Prototype Upgrade
Space Frame on Assembly Rails

5. SNS – High Level Design Requirements
Operating temperature – at or near room temperature
Alignment
0.5 mm in transverse, vertical and axial directions as part of CM assembly
0.5 mm in transverse, vertical and axial directions as part of tunnel installation
Shipping loads
Vertical: +/- 4.0g
Beam-Axis: +/- 5.0g
Transverse +/- 1.5g
Space Frame
Vacuum Vessel
Thermal Shield
Access Port
Cold Mass
SNS PPU CM Cross Section:
Spaceframe unchanged from original SNS CM design

6. Space Frame / Thermal Shield Assembly on Tooling
SNS Medium Beta CM
Space Frame / Thermal Shield Assembly on Tooling

7. SNS – Support Scheme
Nitronic rods (low heat leak, high tensile strength) restrain cavities
- 2 axial, 8 radial per cavity
Inter-cavity bellows
Each cavity is fixed at FPC in axial direction
Cold gate valve (connects to warm-cold beampipe)

8. Space Frame - Design Features
Side view showing ports, VV is transparent
Nitronic Support Rods
Spaceframe is locked to VV after installation
Outer Magnetic Shield attaches to OD
Alignment Steps – cavity flanges:
Survey string on lollipops
Transfer cold mass into space frame (shown) and align
Fiducialize after installation into Vacuum Vessel using access ports and tooling
Bottom section (orange) is removable in order to slide space frame over the string assembly

9. ESS spaceframe: cryomodule overview

10. ESS spaceframe: cross section

11. ESS spaceframe: Support Scheme

12. ESS Design Requirements
Operating temperature – at or near room temperature   spaceframe at 300K supporting each cavities with 8 Ti alloy rods
Alignment     
+/- 1 mm transverse (horizontal2 + vertical2)1/2
+/- 2mm longitudinal    
Shipping loads  (based on XFEL experience)
The cryomodule shall not be exposed to shocks exceeding 2.5g in all the 3 directions of the x-plane, y-plane and z-plane

13. ESS ellipt. cryom transportation
coupler locked for transport
Cavity transverse locking by design
One axial locking per cavity to the Space frame (transportation only)
Spaceframe fixed to vacuum vessel for transport

14. IFMIF LIPAc Cryomodule: cold mass insertion
Due to the couplers, the cold mass must be inserted in the vacuum vessel in two steps:
Horizontal sliding of the frame which is higher than its final position. The frame should be set up so that the couplers are facing the flanges of the vacuum tank.
Vertical motion of the frame until the coupler flanges touch the vacuum tank flanges.
Cold mass
Vacuum vessel
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 14

15. IFMIF: LIPAc Cryomodule: cold mass insertion
When lowering the cold mass inside the vacuum vessel, the operators have to be sure that every interface flange of the power couplers properly mates with its corresponding flange.
This is also the case for the flange of the pumping line of the cavity string (not shown in the figure below).
The operators have also to check that the interface flange between the solenoid and the current lead package faces its corresponding flange of the vacuum vessel.
The operators have also to check that the interface flange of the beam valve faces its corresponding flange of the two doors.
Many interfaces to control during this assembly step

16. IFMIF: LIPAc Cryomodule: cold mass insertion
Many assembly steps have to be performed after the insertion of the cold in the vacuum vessel, with small access room for some operations.
Example:
Installation of the current leads: the welding of the solenoid package wires to the current lead busbars has to be performed through the cryomodule trapdoors.
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 16

17. IFMIF Design Requirements
Support temperature : 4K (from design to be verified) , thermal straps to helium cir.
Alignment:
± 1 mm and ± 10 mrad around the beam axis for solenoids
± 2 mm and ± 20 mrad around the beam axis for cavities

19. DONES: Top loading cryomodule
As all the interfaces but the power couplers and the beam valves are with the top plate, the assembly process is simpler
Most of the work could be performed before the insertion in the vacuum vessel:
Completion of the helium circuitry with leak and pressure tests
Installation of the current leads
Cabling of the sensors and actuators
Installation of the multi layers insulation blankets
Installation of the thermal shield with leak and pressure tests
Less interfaces to monitor during the insertion steps:
interface flanges between the couplers and the vacuum vessel
interface flanges between the beam valves and the vacuum vessel
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 19

20. DONES: Top loading cryomodule
Improvement of the assembly process
LIPAc cryomodule: the titanium frame is used as support of the cavity string in clean room severe requirements on the manufacturing:
For clean room reasons, all the surfaces of the I-beams are machined before welding
After welding, the top surface of the frame are precisely machined (flatness requirement: 0.1 mm/m)
The minimum distance between the flanges of a solenoid and a cavity is 160 mm for a safe removal of the flanges used to position the components  constraints on the motion of the elements along the frame due to the vertical power couplers and the strengthening bars
IFMIF LIPAc
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 20

21. DONES: Top loading cryomodule
Design improvement to ease the assembly process
The frame is not used in clean room, but a trolley with rails and positioning post (as for XFEL and ESS cryomodule)
Conceptual design of the tool used for the assembly of the ESS cavity string
Cavity string to assemble in clean room
Assembly of the cavity string to the frame outside the clean room
Completion of the assembly
N. BAZIN | WPENS 2nd Technical Meeting | October 6th, 2016 | Page 21

22. SARAF Low beta cryomodules
CM1
CM2
CM3
CM4
The twof first ryomodules (CM1 and CM2) are identical.
They house 6 bopt = 0.091, 176 MHz half-wave resonators and 6 focusing superconducting solenoids with steerers.
A 360 mm free space between the fifth cavity and the sixth solenoid package is left to facilitate the matching with next cryomodule.
This space could also possibly house an extra low beta cavity in case of need (CM2).
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 22

23. SARAF High beta cryomodules
CM1
CM2
CM3
CM4
The last two cryomodules (CM3 and CM4) are identical.
They house 6 bopt = 0.181, 176 MHz half-wave resonators and 4 focusing superconducting solenoids with steerers.
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 23

24. cryomodules main specification
1 & 2
3 & 4
Parameters
Units
Cavity b
0.091
0.181
Nb cavities / cryostat
6 (+1) 7
Nb solenoids / cryostat 6 4
Cryostat lenght mm
4590
4980
Output deuteron energy
MeV
6.7 / 11.4
24.5 / 40.1
Output proton energy
3.0 / 7.1
20.8 / 35.0
Beam axis height
1400
Alignment tolerances of Cavities and Solenoids ±2
Pressure of helium bath
MPa
0.125
Maximum allowable pressure
0.2 *
Temperature of helium bath K
4.45
* To be confirmed to stay within Article 3.3 area of PED
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 24

25. SARAF Support Scheme
Support Frame added from the top, after the string assembly Vertical and horizontal tie rods C-shaped element

26. SARAF Design Requirements
Support Temperature: actively cooled to 4K (helium circuit welded to the support). Then we let the support thermalized to about 30K
Alignment :
Cavities and solenoid package positioned within ±1 mm from theoretical linac axis.
Cavities and solenoid package positioned within ±2 mm from theoretical longitudinal position.
Transport:
Vertical : 3g
Lateral : 1.5g
Longitudinal : 5g

27. Transportation to Israel
Mitigation Actions
Transportation to Israel
Transportation by sea = Cheapest solution but:
Several loadings/unloadings  heavy shocks possible during transshipment
Coupler window failure or weakening due to fatigue (resulting from ocean swell)
Risk of contamination of the beam vacuum during shipment (long journey)
Mitigation action:
Transportation by plane
Design complementary constraints: dimensions of the doors of the widespread 747-8F cargo plane: the nose door is 94 in. (239 cm) wide and 96 in. (244 cm) high, while the large side cargo door allows to charge in. (606 cm) long and 96 in. (244 cm) wide loads
H. Dzitko, SRF2015
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 27

28. SARAF transportation
Transport solution not fully validated yet but the starting point is cold mass (CM) and vacuum vessel (VV) disassembled after cryo test and sent by plane.
Module has been designed for CM and VV separated solution this ease to fix sensitive parts of the cold mass (bellows, coupler, etc.).
Once delivered, inspections and tests will be easy

29. Saraf Cryomodule design
Back-Up slides
Saraf Cryomodule design
CEA | 10 AVRIL 2012

30. Design constraints
To limit the beam losses due to its high intensity: particularly restricted space for the component interfaces, which have been minimized as much as possible.
Beam dynamics lattice is indeed very short: only 340 mm space is allowed for the solenoid package (including the beam position monitors and the bellows), 280 mm for the low beta cavity and its tuning system and 410 mm for the high beta cavity and its tuning system.
These requirements define high constraints on the design of these components.
Conceptual design of the low beta cryomodule (SDR SARAF-LINAC, December 2014)
Conceptual design of the SDR is the starting point of this work.
Conceptual design of the low beta cryomodule (PDR SARAF-LINAC, December 2013)
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 30

31. Cryomodule overview
Even if the number of cavities and solenoids depends on the type of cryomodules, the principle is similar for both and the same design approach will be used.
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 31

32. Side / Bottom / top loading
IFMIF: side loading
FRIB: bottom loading
Triumf – Isac II:
top loading
ANL: top loading
Fermilab – SSR1:
side loading / bottom support of the cavity string
PXIE HWR
Cryomodule
ATLAS Upgrade
Top loading configuration, more usual for low beta cavities, was chosen in December 2013 (PDR176)
CERN
HIE Isolde:
top loading
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 32

33. SDR: Support of the cavity string
Like for the IFMIF cryomodule, the cavity string is supported by a stiff frame:
designed and fabricated in order to preserve the relative alignment during thermal cycling,
made of titanium to avoid magnetic issue.
Conceptual design of the low beta cryomodule (PDR SARAF-LINAC, December 2013)
Not possible to directly attach the cavities and the solenoids to the frame
4 m long frame shrinkage: around 6 mm.
Must be compensated by the bellows of the couplers which are interfaced with the vacuum vessel (similar for the bellows of the current leads).
These ones shall already compensate the thermal shrinking of the coupler outer antenna (around 1 mm, perpendicular to the beam axis) and the possible manufacturing errors of the vacuum vessel.
Too many constraints on the bellows
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 33

34. SDR: Support of the cavity string
Solution: leave the cavities and solenoids longitudinal position independent from the titanium frame.
Titanium frame
Sliding attachments to manage the differential thermal deformation between invar rods and frame
Cavity fixed point on the invar rod
Invar rod fixed point
Invar rod
Principle – similar to the IFMIF cryomodule:
C-shaped elements with needle rollers to allow the cavities or the solenoids to move longitudinally along the beam axis.
Loaded spring washer packages keep the pads in contact with the rollers regardless the thermal shrinking.
The elements of the string are attached to an invar rod whose thermal shrinking is low (-0.4 mm/m between 300K and 4K).
The invar rod is fixed on the middle of the titanium frame and sets the longitudinal positions of the elements.
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 34

35. Supporting the cold mass
Requirements:
Shall sustain the weight of the devices with an accurate and reproducible positioning of the components of the cavity string along the beam axis of the accelerator.
Heat loads on the cold part as low as possible.
Several solutions are still under study for the cryomodule: using tie rods and suspended posts.
Configuration 1: using vertical tie rods
Similar to the IFMIF cryomodule and proposed in the SARAF-LINAC Project System Design Report.
Cold mass is hung to the top plate of the vacuum vessel thanks to vertical TA6V tie rods.
Four horizontal rods ensure the lateral position of the cold mass inside the vacuum vessel.
Tension load on each vertical titanium rod has to be adjusted to have a flat frame in order to keep the alignment of the cavity string
Beam axis is set below its nominal position to compensate the thermal shrinking of the titanium rods during the cool down of the cryomodule
IFMIF cold mass with the vertical and horizontal rods
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 35

36. Supporting the cold mass
Configuration 2: using tilted struts
Cold mass is hung to the top plate of the vacuum vessel thanks to tilted struts.
No need of lateral struts.
Beam axis is set below its nominal position to compensate the thermal shrinking of during the cool down of the cryomodule
CERN
HIE Isolde
Triumf – Isac II
ANL: ATLAS Upgrade
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 36

37. Supporting the cold mass
Configuration 3: using antagonist tie rods
In order to compensate the upwards movement of the frame during the cool down due to thermal shrinking of the titanium rods, vertical rods connected to the bottom of the vacuum vessel are used.
Uses titanium alloy rods like the previous one.
Dimensions – length and diameter – of the rods pulling upwards shall be the same as the rods pulling downwards.
Severe constraint for the design of the cold mass as the frame must be in the middle of the vacuum vessel (vertical position).
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 37

38. Supporting the cold mass
Configuration 4: using rigid suspended posts
Rigid posts used in the LHC quadrupole and in the TTF/XFEL/ILC cryomodule .
Several rigid posts made of isolative material with appropriate mechanical properties, a glass-fiber epoxy composite, G10, are used to support the cold mass.
Because of the longitudinally shrinking of the cold mass, one post is rigidly fixed to the top plate of the vacuum vessel while the others longitudinally slide.
XFEL support post
HWR015, IMP
Y. He, “Progress of Chinese ADS Project”, SRF2015,
SARAF-LINAC PDR WP5 | October 13th, 2015
| PAGE 38