SCU Segmented Cryostat Concept M. Leitner, S. Prestemon, D. Arbelaez, S. Myers September 2 nd, 2014

Segmented SCU Layout Allows Servicing Individual Undulator Segments While Keeping Whole String Cold One Cryostat Contains 2 Nominal Two-Meter Undulator Segments M. Leitner - SCU Meeting - September 2, Cryogenic Valves and Removable Low-Loss Bayonets Hard X-Ray LineSoft X-Ray Line Cryogenic Distribution Mass-Produced Cryostats Relief Circuits

Quadrupole Concept Conceptual design of a compact quadropole – Directly attached to the undulator cold mass – Integrated quadrupole strength of 4 T (LCLS-II quad strength) can be obtained – Independently powered coils can be used for x-field correction End corrector Quadrupole Magnet from July 8 th SCU meeting [D. Arbelaez, et.al.]

External Fiducialization Pulsed wire can be placed in the center of the undulator or quadrupoles Wire detectors can be fiducialized and used to find the two ends of the wire Wire position can be related to external fiducials on the cryostat based on the cold magnetic measurements Pulsed Wire Fiducialization Wire inside vacuum chamber Fiducialized Detector can be used to find wire location A second detector will be added to find both ends of the wire from July 8 th SCU meeting [D. Arbelaez, et.al.]

Vertical Alignment with Alignment Quadrupoles Use reference quadrupoles at each end of the 3 m structure – Tuning and calibration is based on the line between the magnetic center of the two quadrupoles – Fiducialization can be performed with a wire measurement and referenced to fiducials on the outside of the cryostat – Allows for beam based alignment by moving the cryostat to find the center of the quads with the electron beam Small Alignment Quadrupole Full Length Quadrupole from July 8 th SCU meeting [D. Arbelaez, et.al.]

LbLb Conceptual Phase Shifter Layout Compact phase shifter uses one end corrector from each undulator and one extra dipole magnet in between Distance between the undulator cores ~ 13 cm for this layout (could be reduced if alignment quadrupoles are not necessary) Joint sections for Nb 3 Sn undulator are 4 cm long for each core End corrector Phase shifter dipole Alignment Verification Quadrupoles / Bx correction Second Field Integral with phase shifter LbLb +k -2k from July 8 th SCU meeting [D. Arbelaez, et.al.]

Example Segmented SCU Layout Undulator Packing Factor Including Diagnostics Sections = 85% M. Leitner - SCU Meeting - September 2, 20147

Two Superconducting Undulator Lines Would Fit Into Existing SLAC Tunnel M. Leitner - SCU Meeting - September 2, Soft X-Ray Line Hard X-Ray Line

Components Of A Single Undulator Line M. Leitner - SCU Meeting - September 2, Cryogenic Valves and Removable Low-Loss Bayonets Existing SLAC Support Posts (For Size Comparison) Cryogenic Distribution Mass-Produced Cryostats Relief Circuits Current Leads Vacuum Valves Vacuum Pumps Vacuum Gauges Bellows For Undulator Removal (Between Cryostats)

Single Undulator Segment Components M. Leitner - SCU Meeting - September 2, Cryogenic Valves And Removable Bayonets Allow Removal Of Undulator Segments While Keeping Undulator Line Cold Cryogenic Distribution (High Pressure LHe And GHe Minimize Pipe Diameters) Cryostat Vacuum Vessel Relief Circuits Are Piped Into A Distribution Return System For Operation And Cool Down Current Leads Vacuum Valve Vacuum Pump Vacuum Gauges Bellows Phase Shifter, Focusing Quad, And BPM Are Inside The Cryostat Cryogenic Control Valves Are Located In Cryostat To Ease Operation Undulator Alignment Based On Pulsed Wire Fiducialization

M. Leitner - SCU Meeting - September 2, Aluminum Thermal Shield Is Actively Cooled On Bottom And Conduction Cooled On The Sides (Potential Location For Magnetic Shields) Single Undulator Segment Components

M. Leitner - SCU Meeting - September 2, K COLDMASS Single Undulator Segment Components Undulator Coil StructureBottom Thermal Shield PlateCryogenic Support Posts LHe Header RT Strongback ~50 K SHIELD AND BEAMIPE

M. Leitner - SCU Meeting - September 2, Single Undulator Segment Components Bottom-Up Design Is Optimized For Mass-Production - Fiberglass Posts Allow Consistent Alignment Cryogenic Support Posts Actual Fiberglass Support Post 4.5 K ~50 K 300 K Room Temperature Strongback Fixed Post Moveable Posts Linear Precision Bearings

M. Leitner - SCU Meeting - September 2, Single Undulator Segment Components Pre-Assembled Coldmass Drops Into Vacuum Vessel – Ease Of Assembly, No Major Tooling Required Connect Beamline Vacuum Weld Final Cryogenic Connections

Thermal Transitions, Focusing Quadrupole And Cold BPM M. Leitner - SCU Meeting - September 2, Valve Thermal Transition (Bellows) Vacuum Chamber 50 K Intercept Focusing Quad Cold BPM Thermal Transition (Bellows) Valve, Pumping, Gauges, Beamline Bellows 50 K InterceptVacuum Chamber Alignment System

SCU Assembly Steps Prepare Room Temperature Strongback M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Place Linear Bearings And Pre-Assembled Fiberglass Posts M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Place Bottom MLI Blankets (Not Shown) And Thermal Shield Bottom Plate With Pre-Welded Cooling Lines M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Place First, Pre-Fiducialized Undulator Coil Section M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Place Second, Pre-Fiducialized Undulator Coil Section M. Leitner - SCU Meeting - September 2, Rigid Connection Small Quad Dipole Phase Shifter Dipole Large Quad

SCU Assembly Steps Connect And Align Vacuum Chamber, Connect Thermal Transitions M. Leitner - SCU Meeting - September 2, Vacuum Chamber Alignment Mounts Thermal Transition And BPM

SCU Assembly Steps Weld Pre-Fabricated LHe Header, Wrap With Multi-Layer Insulation M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Assemble Thermal Shield And Wrap With Multi-Layer Insulation M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Drop Coldmass Into Vacuum Vessel, Connect Beamline Vacuum M. Leitner - SCU Meeting - September 2, Beamline Vacuum Bolted Flange Connection Beamline Vacuum Bolted Flange Connection

SCU Assembly Steps Connect Pre-Routed Current Lead Assemblies M. Leitner - SCU Meeting - September 2, Current Feedthroughs

SCU Assembly Steps Weld Final Cryogenic Connections To Bayonet Box M. Leitner - SCU Meeting - September 2, Bayonet Box (Part Of Vacuum Chamber)

SCU Assembly Steps Close Cryostat Vacuum Vessel M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Connect Cryogenic Relief Circuits M. Leitner - SCU Meeting - September 2, Relief Valves Different Circuits For Cooldown and Regular Operation

SCU Assembly Steps Connect Beamline Valves, Vacuum Pumps And Gauges M. Leitner - SCU Meeting - September 2, Interstitial Vacuum Equipment

SCU Assembly Steps Prepare For Checkout And Lifting M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Assemble To Support System M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Installation And Alignment In Tunnel M. Leitner - SCU Meeting - September 2,

SCU Assembly Steps Connection To Cryogenic Distribution Line M. Leitner - SCU Meeting - September 2, Cryogenic Relief Connections Cryogenics Expansion Joint Box Shut-Off Valves Low-Loss Bayonets Control Valves (Hidden, On Cryostat Side)

Summary Segmented cryostat design takes full advantage of LBNL alignment strategy utilizing end quadrupoles Cryostat with low-loss fiberglass posts employing bottom-up assembly is optimized for mass-production and superior alignment A segmented, superconducting undulator design allows servicing of individual undulator segments while keeping rest of undulator strings cold Minimized thermal cycling assures consistent undulator alignment High-quality bayonets and cryogenic valves assure low-loss cryogenic operation M. Leitner - SCU Meeting - September 2,

Next Steps Develop cryostat heat load budget Develop cryogenic flow diagram Based on flow diagram optimize cryogenic distribution system M. Leitner - SCU Meeting - September 2,