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Conceptual Cryomodule Design for the CW HE lmholtz LI near AC celerator at GSI. F . Dziuba 1,2,4
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Conceptual Cryomodule Design for the CW HElmholtzLInearACcelerator at GSI F. Dziuba1,2,4 K. Aulenbacher1,2,4, W. Barth1,2, M. Basten3, C. Burandt1,2, M. Busch3,V. Gettmann1,2, M. Heilmann2, T. Kürzeder1,2, S. Lauber1,2,J. List1,2 ,M. Miski-Oglu1, H.Podlech3, A. Schnase2,M. Schwarz3, S.Yaramyshev2 • 1HIM, Helmholtz Institute Mainz, Mainz, Germany • 2GSI Helmholtzzentrum, Darmstadt, Germany • 3IAP, Goethe Univ. Frankfurt, Frankfurt, Germany • 4KPH, Johannes Gutenberg Univ., Mainz, Germany
Superconductingcw HELIAC RecentlayoutofthefuturesuperconductingcwHELIAC Layout properties • Multigap CH cavities • Cavities with short lengths (<1m) and small transverse dimensions (<0.5 m) • Modular construction with 4 cryomodules • Each containing 3 CH cavities, 1 buncher, 2 solenoids • Ea=5.5MV/m enables compact linacdesign • First step Demonstrator project
Design ofthe Demonstrator Cryomodule • Design properties • Universally design, multi-use • Magnetic shield coupled to 300 K • Support frame located within thermal shield • Various flanges for power couplers, tuners, electrical feedthroughs etc. • LHe provided by 250 l dewars • Transversal tolerance during cool down ± 0.1 mm • Several fiducials for component alignment LN2reservoir (50 l) LHereservoir (100 l) 2.2 m Layout ofthe horizontal demonstratorcryomodule Superconducting 9 T solenoids Superconducting 217 MHz CH cavity Support frame
Support Frame & Alignment Nuclotron suspension Frame suspended on outer vessel Tuners CH cavityandtwosolenoidsmounted in thesupportframe Power coupler Alignment of all components to each other ⇾ common component axis Transfer of common component axis to support frame ⇾string integration Transfer of frame axis to cryomodule⇾vessel closing Alignment of cryomodule axis to beam line
Assembly of Cold String at GSI Successfullytestedwith beam! Clean room at GSI Outer part: ISO6 Inner part: ISO4 Integration into Cryostat
Next Step: Standard Cryomodule Layout • New cryomodule layout optimized for the cw HELIAC requirements • Cryomodule containing 3 CH cavities , 1 buncher cavity and 2 solenoids • Operated at 4.2 K, required cooling power 60 W (total) • Each component equipped with own He jacket and magnetic shield • LHe supplied by the 700 W GSI cryo plant
New Cryomodule Layout • Design features & improvements • 4 rectangular service doors • On sitealignmentofeachcomponenttothe beam linewith a lasertracker • Assemblyof RF power couplersandsolenoidcurrentleadsthroughthedoors • Nuclotronsuspensionofsinglecomponents • Segmentedsupportframe, mechanicallyandthermallycoupledtoouter tank (300 K) • Thermal shieldinsideofsupportframe • Segmented frame standing on dedicated points of the bottom of the cryostat • Deformations of outer vessel during evacuation do not affect the position of the frame • Trans. position of each component will be preserved within ± 0.1 mm during cool down
New Cryomodule Layout • Alreadyordered, expecteddelivery in 04/2020 • BuiltbyCryoworld, AdvancedCryogenic, Netherlands • Size oforder: 520k€
AssemblyProcedure: Step 1 CH0 • Step 1: • Inside the clean room the cold string is mounted on a rail system • All components will be connected with bellows • Their relative position to each other is fixed with bolts • Cold string is terminated with gate valves and evacuated B1 S1 CH1 CH2 S2 Railguidedsupportsystem
AssemblyProcedure: Step 2 Mountingrack Segmentedframe(top part) • Step 2: • Cold string is moved along the rail system outside the clean room • Top part of segmented frame is assembled to the mounting rack • Rough alignment of the cold string with the segmented frame
AssemblyProcedure: Step 3 • Step 3: • Suspension of individual components intothe segmented frame • Removal of rail guided supports • Assembly of He distribution piping
AssemblyProcedure: Step 4 • Step 4: • Bottom of segmented frame is connected to the top part • Remaining nuclotron suspensions will be assembled • Alignment of single components • Thermal shield is closed except door regions Segmentedframe(bottompart)
AssemblyProcedure: Step 5 • Step 5: • Frame is shifted into the cryostat using an internal rail system • Internal rail system is locked • Assembly of warm parts of the power couplers • Final alignment of components with laser tracker • Closing of remaining thermal shield and outer vessel
Acknowledgements Thankyouverymuchforyourattention! Improvments, comments, concernsanddoubts arewelcome! Collaborationpartners GSI / HIM KPH - Johannes Gutenberg University Mainz IAP - Goethe University Frankfurt
Things toOptimize LN2reservoir (50 l) • Things to optimize • Assembly procedure of components into the support frame regarding longer cold strings • Individual alignment of components after integration of cold string into cryostat not possible • Alignment of components in longer cold strings is difficult due to deformations • No convenient access for assembly & maintenance (power coupler, connection of He exhaust etc.) • Vessel made from stainless steal instead of aluminium ⇾ abrasion, dust, durability • Nuclotron suspension is reliable within required tolerances of ± 0.1 mm! LHereservoir (100 l) 2.2 m Layout ofthe horizontal demonstratorcryomodule Superconducting 9 T solenoids Superconducting 217 MHz CH cavity Support frame
RF Design ofthe Demonstrator Cavity CH0(based on beam dynamic design by S. Mineav 2009) Statictuner Dynamic tuner Inclinedstem Preparation ports 3rd superconducting CH cavity developed at IAP Manufacturered at Research Instruments Most complex superconducting cavity ever been built Bulk Niobium (RRR 300) from Tokyo Denkai Helium vessel
Short CH Cavity Design Design parameters of short CHcavities CH1 & CH2 PhD thesis of M. Basten, IAP, Frankfurt University CH1 w/o He vesselhasbeenalready RF tested at 4 K @ IAP
Cavity Tuning Rotation axis Spindle Lever • Main propertiesofthetuningsystem: • Enablesslow & fast frequencyadjustment • Capacitivebellowtuner • Max. mechanicaldisplacement ±1 mm (≈ ±60 kHz) • Requiredforce < 800 N • Lever withpivotpointratio ≈ 2:1 • Gearreductionratio 50:1 • Piezoactuator ‚connected in series‘ withslowtuningunit • Requireddisplacementofpiezo ±4µm (≈ ±240 Hz) Piezo actuator Steppingmotor PhD thesis of M. Amberg, 2015KPH, Mainz University Bellow tuner 50 mm
High Power Coupler 502.6 mm Outerconductor Diagnosis port Outerconductor 3 1/8‘‘ Inner conductor Bellow Warm part Coldpart Coupler design based on the work of S. Kazakov, Fermilab 300 K Warm window 4 K 70 K Coldwindow • Coaxial antenna setup (inner conductor made from copper) • Capacitivecouplingof RF power • Devided into cold & warm part by 2 ceramic windows (Al2O3), TiN coated • 5 kW cw operation, cold window connected to LN2 supply • 216.816 MHz operation frequency with 33 MHz bandwidth
Matching Line – Demonstrator HLI provides Ar11+, Ar9+, Ar6+, He2+ @ 1.4 MeV/u QD QD QT BSM Mob EMI HLI 1,4 MeV/u cw Demonstrator P R1 R2 G T T P P x | y QT: Quadrupol triplet R: Re-Buncher (QWR) QD: Quadrupole doublet x|y: Steering magnets G: Profile Grid T: Beam current transformers for transmission measurement P: Phase probes for TOF measurement BSM: Bunch shape monitor (Feschenko monitor) EMI: Slit-Grid emittance measurement device
Timeline Funding of CM1 for the HELIAC Ordering of CH cavities CH1 & CH2 Tendering of CM1, solenoids S1 & S2, buncher cavity B1 Delivery of CH1 & CH2 Delivery of CM1, S1, S2 , B1 and assembly @ HIM 4K test of fully equipped cryomodule CM1 @ GSI Beam test @ GSI 02/2015 09/2016 10/2018 02/2019 04/2020 09/2020 10/2020