1. Low Beta Cryomodule Development at Fermilab Tom Nicol March 2, 2011

2. Concepts of SC CW 3GeV, 1mA Linac N.Solyak, Project-X Linac design2 FNAL PrX Retreat, Nov.2, 2010 SSR0SSR1SSR2β=0.6β=0.9 325 MHz 2.5-160 MeV ILC 1.3 GHz 2-3 GeV 650 MHz 0.16-2 GeV MEBTRFQ H - gun RT (~15m) Initial configuration. Now changed to reduce gradient in HE650

3. TTC WG-2 - March 2, 2011Page 3 Project X optics layout (version 3.7.4)

4. TTC WG-2 - March 2, 2011Page 4 SSR cryomodule configurations (version 3.7.4) (18 / 18) (10 / 10) (10 / 5)

5. TTC WG-2 - March 2, 2011Page 5 Front end optics (version 3.7.4)

6. TTC WG-2 - March 2, 2011Page 6 Segmentation features “Coarse” segmentation –Large diameter interconnect bellows at each end of each module. –All internal piping connection from one module to another are made inside the interconnect region, usually by a bellows. –Continuous insulating vacuum space (at least between vacuum breaks). “Fine” segmentation –One or more cryogenic distribution boxes at each module. –The only direct connection between modules is the beam tube. –Internal cold-to-warm transitions required at each end of each beam tube.

7. TTC WG-2 - March 2, 2011Page 7 Considerations Inter-cavity spacing between cryomodules. Alignment of elements inside individual cryomodules (inter-cryomodule segmentation). Warm diagnostics requirements. Total cryomodule heat load (affects heat exchanger size). Pressure relief size and frequency. Cooldown and warm-up time. Cost, including interconnects, feed cans, transfer lines, tunnel length, etc. Cryomodule pipe sizes. Technical risks in cryomodule design. Cryomodule installation, maintenance, and replacement time and effort. Considerations pertain to both cryo and vacuum segmentation. The type and degree of segmentation will likely be driven by requirements, not the other way around.

8. TTC WG-2 - March 2, 2011Page 8 SSR cavity and cryomodule assumptions “Fine” segmentation in all SSR sections, i.e. each cryomodule is self- contained. Cavities and solenoids operate at 2 K. 2 K heat exchanger in each cryomodule. Cavity string supported by warm strongback. Conduction cooled current leads for all magnet coils. Cavity MAWP = 2.5 bar warm, 4 bar cold. Button BPM’s between each cavity and solenoid. Cavities and solenoids individually aligned. No adjustment after final assembly into the cryomodule, but verifiable via optical windows. Warm magnetic shield inside vacuum vessel wall capable of reducing residual field to 10  T. Cold magnetic shield on each solenoid.

9. TTC WG-2 - March 2, 2011Page 9 Cavity and solenoid mounted on separate supports. Initial solenoid and cavity mounting scheme Strongback Becomes cumbersome when element spacing decreases, as in SSR0.

10. TTC WG-2 - March 2, 2011Page 10 SSR0, solenoid, and BPM assembly 610 mm Reduced element spacing, especially for SSR0 made the original scheme less attractive. Solenoid is the same one used in the HINS front end, RT section. 2 K operation gives additional field and margin needed for SSR0 and SSR1 cryomodules.

11. TTC WG-2 - March 2, 2011Page 11 SSR1, solenoid, and BPM assembly 750 – 800 mm

12. TTC WG-2 - March 2, 2011Page 12 SSR0 cavity string Support post C/W transition Strongback BPM

13. TTC WG-2 - March 2, 2011Page 13 Cavity string, piping, leads, etc. Solenoid and shield C/W transition Current lead assembly Solenoid pedestal 2-phase header Heat exchanger Check valve (may omit)

14. TTC WG-2 - March 2, 2011Page 14 Prototype cryomodule Heat exchanger and relief line Cryogenic feeds and controls RF input couplers Current lead assemblies Cavity vacuum pumpout Alignment viewports

15. TTC WG-2 - March 2, 2011Page 15 Domed end alternative

16. TTC WG-2 - March 2, 2011Page 16 Prototype cryomodule – flat ends (SSR0 cavities shown)

17. TTC WG-2 - March 2, 2011Page 17 Prototype cryomodule – domed ends (SSR0 cavities shown)

18. TTC WG-2 - March 2, 2011Page 18 Prototype cryomodule – flat ends (SSR0 cavities shown)

19. TTC WG-2 - March 2, 2011Page 19 Prototype cryomodule – domed ends (SSR0 cavities shown)

20. TTC WG-2 - March 2, 2011Page 20 SSR estimated heat loads SSR0 (qty 1)Each unit Mult Total 18 cavities, 18 solenoids70 K4.5 K + 2 K70 K4.5 K + 2 K Input coupler static2.370.671842.712.1 Input coupler dynamic00.25180.04.5 Cavity dynamic load00.5180.09.0 Support post2.760.411849.77.4 Conduction lead assembly36.814.4418662.4259.9 MLI (total 70 K +2 K)62.22.9162.22.9 Cold to warm transition0.720.0921.40.2 Total 818.4295.9 SSR1 (qty 2)Each unit Mult Total 10 cavities, 10 solenoids70 K4.5 K + 2 K70 K4.5 K + 2 K Input coupler static2.370.671023.76.7 Input coupler dynamic00.25100.02.5 Cavity dynamic load00.8100.08.0 Support post2.760.411027.64.1 Conduction lead assembly36.814.4410368.0144.4 MLI (total 70 K +2 K)48.12.2148.12.2 Cold to warm transition0.720.0921.40.2 Total 468.8168.1 SSR2 (qty 4)Each unit Mult Total 10 cavities, 5 solenoids70 K4.5 K + 2 K70 K4.5 K + 2 K Input coupler static2.370.671023.76.7 Input coupler dynamic00.25100.02.5 Cavity dynamic load02.9100.029.0 Support post2.760.411027.64.1 Conduction lead assembly36.814.445184.072.2 MLI (total 70 K +2 K)48.12.2148.12.2 Cold to warm transition0.720.0921.40.2 Total 284.8116.9 SummaryEach unit Mult Total SSR0, SSR1, SSR270 K4.5 K + 2 K70 K4.5 K + 2 K SSR0818.4295.91818.4295.9 SSR1468.8168.12937.6336.2 SSR2284.8116.941139.2467.7 Total 2895.21099.8 Notes: 1. Assume 2 pairs of 50 A and 1 pair of 200 A leads per solenoid. 2. Cavity dynamic loads from N. Solyak.

21. TTC WG-2 - March 2, 2011Page 21 2 cavities in-house, one from Zanon, one from Roark. 2 are in-process in India. An order for 10 more is in-process at Roark/Niowave. SSR1 cavity

22. TTC WG-2 - March 2, 2011Page 22 Parts for 2 helium vessels are in-house, one of which is welded. One prototype tuner is being tested warm. Dressed SSR1 Cavity and Tuner

23. TTC WG-2 - March 2, 2011Page 23 2 supports built to date, one proof-tested to failure, one installed in the test cryostat. Support post

24. TTC WG-2 - March 2, 2011Page 24 Input coupler 3 couplers are in-house and tested. One currently installed in test cryostat. Design modifications in-process to reduce weight. Coaxial design, adjustable, 76.9 mm outer/33.4 mm inner, two disk-type ceramic windows.

25. TTC WG-2 - March 2, 2011Page 25 Alternate design input coupler

26. TTC WG-2 - March 2, 2011Page 26 Modeled after similar leads designed at CERN. 4 leads at 50 A, 2 leads at 200 A. Thermal intercepts at 80 K and 5 K. Sample leads currently being fabricated to verify thermal performance of conductor and intercepts. Conduction cooled current lead assembly

27. TTC WG-2 - March 2, 2011Page 27 SSR0 BPM assembly Beam 205 mm 270 mm 4-1/2” fixed Conflat 4-1/2” rotatable Conflat 1-1/2” OD, 30 mm ID tube Cavity end

28. TTC WG-2 - March 2, 2011Page 28 Test cryostat installed in MDB

29. TTC WG-2 - March 2, 2011Page 29 Small 2-phase pipe OK for steady-state 325 MHz steady-state results Number of cavities vs. 2-phase pipe size SSR0 SSR1 and SSR2 From Tom Peterson

30. TTC WG-2 - March 2, 2011Page 30 325 MHz steady-state results Number of cavities vs. 2-phase pipe size From Tom Peterson For mechanical space reasons we would like to use a 5-inch OD tube in our 325 MHz CM. The practical limit then is 8 cavities in series for emergency venting flow. Emergency venting of 8 cavities results in 1 bar pressure drop Emergency venting of 10 cavities results in 2 bar pressure drop

31. TTC WG-2 - March 2, 2011Page 31 Steady-state flow requirement is relatively low. –4 cm ID is adequate to keep a low helium vapor velocity (< 5 m/sec) with over 20 cavities in series, such as one long SSR0 cryomodule (neglecting cross-section occupied by liquid, so we have to add to the diameter for a liquid level). Venting for loss of cavity vacuum determines 2-phase pipe size. –A 3 inch air inlet hole implies roughly a 14 cm 2-phase pipe and a 19 cm vent line. –Basically 5 - 6 inch and 8 inch diameter, respectively. Prototype SSR cryomodule will incorporate these pipe sizes even though they would not be required for this small cryomodule alone. 325 MHz 2-Phase pipe conclusion

32. TTC WG-2 - March 2, 2011Page 32 FRIB “bathtub” design cryomodule

33. TTC WG-2 - March 2, 2011Page 33 Optics design is in-process and seems to be converging. SSR1 cavity design complete. SSR0 nearly complete. SSR2 in-process. Helium vessel designs for all are in-process (1 st generation SSR1 helium vessel will not be used in prototype cryomodule). Prototype cryomodule design in-process. It will contain 4 cavities and 4 solenoids, either SSR0 or SSR1. Final configuration to be determined. Functional specification for the prototype is complete and those for the production SSR cryomodules are in-process. Many sub-component designs are complete or nearly so. –Strongback –Support post –Input coupler –Current lead assembly –First generation tuner –BPM Need to work out assembly procedure details, especially for the longest cryomodules. Test cryostat for single, dressed cavity tests is installed. A 2 K conversion is being designed. Weighing pros and cons of adopting the “bathtub” style cryomodule. Status and plans