LCLS-II SRF Linac Multi-lab partnership to build CW FEL based on SRF at SLAC. Marc Ross 13 January 2014

Transcription

1 LCLS-II SRF Linac Multi-lab partnership to build CW FEL based on SRF at SLAC Marc Ross 13 January 2014

2 What are the technical and practical limits for DF? 1st limit: Heat load at 2K for each cryomodule should not exceed ca. 20 W 2nd limit: Heating of the HOM couplers must not cause quenching of the cavity 3th limit: An upgrade of the cryogenic plant should be doable 4th limit: New RF-sources will be added to klystrons used for the sp operation Jacek Sekutowicz;

3 LCLS-II SRF: 4 GeV up to 300 micro-amp CW superconducting linac based on TESLA / ILC / E-XFEL 1.3 GHz technology Develop cavity process for high-q0 production Develop CW cryomodule design and operations scheme for 110 2K / CM (or better) based on high-q0 cavity process Use industrial capability for 1) dressed-processed-cavity, 2) coupler, and 3) vacuum-vessel/cold-mass production Develop single-source multi-cavity precision vector sum control Will use single-source single-cavity Adapt Jlab CHL-2 (12 GeV Upgrade) Cryoplant for SLAC 3

4 LCLS-II SRF Linac Closely based on the European XFEL / ILC / TESLA Design Under development ~ 20 years with > 1000 cavities until 2015 (inc. 800 for E-XFEL) LCLS-II Linac consists of: Component Count Parameters Linac 4 cold - segments 35 8 cavity Cryomodules (1.3 GHz) 3 4 cavity Cryomodules (3.9 GHz) 1.3 GHz Cryomodule 8 cavities/cm 13 m long. Cavities + SC Magnet package + BPM 1.3 GHz 9-cell cavity MV/m; Q_0 ~ 2.7e10 (avg); 2 deg. K; bulk niobium fine-grain sheet-metal Cavity Auxiliary per cavity Coaxial Input Coupler; 2 HOM extraction coupler; lever-type tuner Injector 1 1 special cryomodule (TBD) 4

5 LCLS-II SRF: 4 GeV up to 300 micro-amp CW superconducting linac based on TESLA / ILC / E-XFEL 1.3 GHz technology Develop cavity process for high-q0 production Develop CW cryomodule design and operations scheme for 110 2K / CM (or better) based on high-q0 cavity process Use industrial capability for 1) dressed-processed-cavity, 2) coupler, and 3) vacuum-vessel/cold-mass production Develop single-source multi-cavity precision vector sum control Will use single-source single-cavity Adapt Jlab CHL-2 (12 GeV Upgrade) Cryoplant for SLAC 5

6 Surface Resistance vs Temperature (2003): The surface resistance R s of a nine-cell TESLA cavity vs Tc / T. (P. Schmüser) Q 0 = G R s LCLS-II LCLS-II: Q_0>2.7e10 T=2 deg (Tc/T=4.6) R_s < 10 nω Improvement to R BCS required 6

7 High Q0: Fermilab-developed gas-doping process Fermilab has developed a cavity processing recipe that results in high quality factors (>3E10) at operating gradients between 10 and 20 MV/m. This recipe is in its first phase of development and requires further investigation to be mature enough for large project implementation. In 2014 Fermilab will lead a program in collaboration with Cornell and JLab to bring this about. The primary goal is to develop a reliable and industrially compatible processing recipe to achieve an average Q0 of 2.7E10 at 16 MV/m in a practical cryomodule. To reach this goal, the collaborating institutions will process and test single-cell and 9-cell 1.3 GHz cavities in a successive optimization cycle. The deliverable is industrial capability and cost-effective production yield. To be applied to LCLS-II construction. 7

8 C. Reece : 20 each 1-cell test result range 8

9 N total Mean Standard Deviation Minimum Median Maximum Q e10 1.2e10 3.2e10 4.0e10 7.4e10 4 EP+120C bake 3 LCLS-II spec Fermilab nitrogen/argon doping technology Count E E E E+010 Q0 (Eacc=16 MV/m, T=2K) Romanenko, Grassellino

10 Jlab / Fermilab Cross-Check: LCLS-II 10

11 First gas treated nine cell LCLS-II Proof-of-principle LCLS-II Anna Grassellino, Fermilab TD

12 LCLS II Cavity Processing Recipe Cavities ready for Processing HPR (Class 100) - 8hr 1. Degassing Temp 2. Doping Gas 3. Gas Pressure Temp 5. Exposure Duration Pre-process Inspection & Thickness Measurements Bulk EP (120um to 150um) Post-process Inspection & Thickness Measurements 1- pass HPR UHV High Temp Bake N 2 g/ar (800C for 2 hrs) Partial Assembly(Class 10) HPR (Class 10) - 12hr Full Assembly (Class 10) Vacuum Leak Check (Class 10) Pass Cavity Dressing (helium vessel weld) Repair Leak Fail RF Tuning HOM Notch tuning 1. Temperature: 15-20C 2. Removal Amount: 2-30 μm Light EP (5-10 um) Alcohol Rinse Ship Cavity VTA Testing FNAL/JLab A. Rowe 12

13 Breakdown in surface resistance components Surface treatment options R BCS (16 MV/m,2K) EP + 120C (fine grain) ~10 ~4-8 BCP + 120C ~10 ~8 EP+120C + HF rinse ~10 <3 Large grain (EP +120C) ~10 <3 Nitrogen bake ~4.5 <3 R 0 (16 MV/m) (total, measured in vertical test) Q=G/Rs for Q = 2.7e10 (2K) max total Rs=10 2K : Margin on residual (with gas bake) 5.5 nohm Anna Grassellino, Fermilab TD R 0 = R mag + R res R 0 is independent of T

14 800C 10 mins +different amount of EP post gas bake 5.00E E E E E E E E E E+09 Q at 2K, 16 MV/m: -2.7e10 (5 microns) -4.4e10 (7 microns) -3.2e10 (10 microns) +5 microns EP +7 microns EP +10 microns EP 0.00E Anna Grassellino, Fermilab TD 2/3 down at +/- 3 um

15 Post-doping EP depth: December 2013 preliminary result 10% change over 4 um 15

16 LCLS II Cavity Processing R&D Process Step Parameter Space Description High Temperature Vacuum Bake Degassing Temp: C Doping Gas: Ar, N 2 Doping Gas Pressure: 1E-2 mbar -5E-01 mbar Doping Temperature: C Exposure Duration: seconds to hours Light Electropolishing Temperature: 15-20C Removal Amount: 2-30 μm Hydrogen degassing occurs first in process followed by exposure at temperature of doping gas. Duration of exposure and diffusion rate depend on process temp, gas concentration, and duration length. Removal amount and temperature depends on achieving ideal doping layer Allan Rowe, Fermilab TD

17 LCLS-II SRF: 4 GeV up to 300 micro-amp CW superconducting linac based on TESLA / ILC / E-XFEL 1.3 GHz technology Develop cavity process for high-q0 production Develop CW cryomodule design and operations scheme for 110 2K / CM (or better) based on high-q0 cavity process Use industrial capability for 1) dressed-processed-cavity, 2) coupler, and 3) vacuum-vessel/cold-mass production Develop single-source multi-cavity precision vector sum control Will use single-source single-cavity Adapt Jlab CHL-2 (12 GeV Upgrade) Cryoplant for SLAC 17

18 Cryomodule Collaboration Fermilab is leading the cryomodule design effort Extensive experience with TESLA-style cryomodule design and assembly Jefferson Lab and Cornell are partners in design review, costing, and production Jefferson Lab sharing half the 1.3 GHz production - Recent 12 GeV upgrade production experience Argonne Lab is also participating in cryostat design Beginning with system flow analyses and pipe size verification 18

19 Linac cryogenic heat loads for Q0 = 2.7 x 1010 Cryomodule Heat Loads 40 K 5 K 2.0 K Predicted static heat per cryomodule (W) Predicted dynamic heat per powered cryomodule (W) Predicted total linac heat (kw) Note: these heat loads are best estimates, no uncertainty margins added here. For helium vessel and cryomodule thermal design, a 50% margin for heat load is taken. We also design cryomodule so as fully to retain a 1.8 K option (lower vapor densities). 19

20 1.3 GHz cryomodule modifications for LCLS-II We start with the TESLA Type 3+, XFEL, and Type 4 designs Modifications for high heat loads Larger chimney pipe from helium vessel to 2-phase pipe Larger 2-phase pipe (4 inch OD) Closed-ended 2-phase pipe Separate 2 K liquid levels in each cryomodule 2 K JT valve on each cryomodule End lever tuner and helium vessel design for minimal df/dp Two cool-down ports in each helium vessel for uniform cool-down of bimetal joints No 5 K thermal shield But retain 5 K intercepts on input coupler Input coupler design for 7 kw CW plus some margin 20

21 LCLS-II cryomodule schematic 21

22 LCLS-II Preproduction Cryomodule 1.3 GHz, modified for CW operation Total length ~12.2 m Nearly the final LCLS-II cryomodule design 22

23 LCLS-II Preproduction Cryomodule 8 cavities (End Tuner) + 1 Splittable Quad (V. Kashikhin), 6 Current Leads ~50A -80K shield (CM3) -4K intercepts -Global magnetic shield not shown -JT Valve -Splittable Quad -BPM -Gate Valve 23

24 LCLS-II SRF: 4 GeV up to 300 micro-amp CW superconducting linac based on TESLA / ILC / E-XFEL 1.3 GHz technology Develop cavity process for high-q0 production Develop CW cryomodule design and operations scheme for 110 2K / CM (or better) based on high-q0 cavity process Use industrial capability for 1) dressed-processed-cavity, 2) coupler, and 3) vacuum-vessel/cold-mass production Develop single-source multi-cavity precision vector sum control Will use single-source single-cavity Adapt Jlab CHL-2 (12 GeV Upgrade) Cryoplant for SLAC 24

25 Power vs Q_ext vs microphonics: From high Q0 to high Q_ext Required forward power vs Q ext for various cavity mechanical instability RMS ( microphonics ) nominal ERL E acc (close to LCLS-II) no beam loading LCLS-II close to optimum LCLS-II LCLS-II adjustable Q ext Neumann, Liepe et al,

26 m Mechanical Instability Spectrum: compare two systems (Berlin HZB and Fermilab) 26

27 Lorentz Force Detuning (Jlab / CEBAF) LCLS-II Lorentz Force Detuning offset 27

28 Cryomodule Production Plan Industrial Cavity Production (established for E-XFEL, ILC) Produce two streams of identical LCLS-II production CM at FNAL and JLab Tightly coordinated activity among partner labs Common procedures, common test performance database, common travelers, etc. Design, engineering development, R&D, validation of parameters, core staff training, and infrastructure updates are complete before production starts All cavities and cryomodules go in the linac Three years (including ramp-up) to make cryomodules 28

29 Capabilities and Infrastructure: FNAL/ANL Cavity Processing Electropolishing Ultrasonic degreasing Dressed cavity prep for CM or HT ass y Re-processing High-pressure rinse Ass y & Leak check 29

30 Capabilities and Infrastructure: FNAL cavity tests Vertical Test Stands 30

31 Capabilities and Infrastructure: FNAL CM assembly Class 100 Class 10 Cavity String Assembly Clean Room Cavity String Assembly Cold Mass Assembly Cryomodule Transport Final Assembly Final Assembly 31

32 Capabilities and Infrastructure: FNAL 3.9 GHz CM 32

33 Capabilities and Infrastructure: FNAL 1.3 GHz CM Ass y WS2:7d (7) WS1: 9d (6) WS0: 5d (2) WS3: 5d (10) WS5: 10d (8) WS4:5d (10) WS6: 4d (4) Total = 45 days Workstation: duration (#people) 33

34 Capabilities and Infrastructure: FNAL CM Test ~100M investment

35 Cryomodule Test Facility FNAL - (CMTF) Cryoplant (blue) Distribution box (silver) Cryomodule Test Stand (CMTS) H - beam test cave

36 Capabilities and infrastructure: FNAL CM test facility Existing infrastructure for one cryomodule test stand (CMTS) Project to provide RF source/distribution, and cryo distribution in cave Cryoplant (blue) Distribution box (silver) H - beam test cave 36

37 JLab SRF Facilities Existing and required additions Vertical Test Area (VTA), significant extra capacity - 8 dewars (4 available for LCLS production, 8 cavities per week capacity) Peak testing 4 cavities per week required Routine 2 cavities per week required - Low level and high power RF on hand Clean room for cavity string assembly, extra capacity supported by exisitng tooling plan - ISO 4 - Dedicated drying and assembly bays - Modular wall system - Need LCLS specific cavity string assembly tooling, two sets to support production rate Cryomodule assembly are, significant extra capacity - 4 bays, two with existing rail systems, two work station per rail - 2 rails needed for LCLS - Need LCLS specific cryomodule tooling, final design to be completed at Jlab to adapt exisitng tooling to Jlab system Cryomodule test facility (CMTF), pacing facility at 5 shifts per week - additional throughput available by using more than 5 shifts per week (weekends and multiple shifts) - Single shielded cave - 2K cryogens available, high throughput investment needed - New feed cans for LCLS cryomodules needed - Borrow HP RF from the project LCLS-II - DESY New Visit, LLRF Jan needed 13, 2014 for 1300 MHz 37

38 TEDF Construction Complete Start 2* 1 * Ship * See next page 38

39 JLab Cryomodule Assembly Rails used for CEBAF, SNS,

40 Project Collaboration 50% of cryomodules: 1.3 GHz Cryomodules: 3.9 GHz Cryomodule engineering/design Helium distribution Processing for high Q (FNAL-invented gas doping) 50% of cryomodules: 1.3 GHz Cryoplant selection/design (01-08) Processing for high Q (gas doping) Undulators e - gun & associated injector systems Undulator Vacuum Chamber Also supports FNAL w/ SCRF cleaning facility Undulator R&D: vertical polarization R&D planning, prototype support processing for high-q (high Q gas doping) e - gun option LCLS-II DESY AccSeminar

41 Technical Integration Project Office Technical Deputy D. Schultz LCLS-II Project Project Manager M. Reichanadter Systems Integration L. J. Plummer Project Director John Galayda Project Office R. M. Boyce Physics Support T. Raubenheimer ES&H J. Healy, I. Evans Purchasing B. Miller, J. Pearman(deputy) Organization Partner Laboratories Senior Team Leaders ANL: FNAL: JLAB: LBNL: Cornell: E. Gluskin R. Stanek G. Neil J. Corlett G. Hoffstadter C. Ginsburg R. Wells Cryogenic Systems Experiment Systems Accelerator Systems Infrastructure System Manager: System Manager: System Manager: System Manager: M. Ross M. Rowen J. Q. Chan R. Law FERMILAB LBNL Cryomodules 1 LBNL Injector Source Infrastructure East Undulators Beam Switchyard Beam Trans. Hall & Und. Hall FERMILAB Injector (SLAC) Front End, Beam Dump & NEH Cryogenics Distribution Sys. Undulator system (SLAC) Infrastructure West Sectors 0-10 JLAB Linac Cryoplant Cryomodules 2 JLAB X-R Transport & Exptl.Sys. Transport Lines Engineering Design & ESH Cryoplant LCLS-II DESY AccSeminar Controls 41

42 Cryomodule schedule and milestones (L4) WBS Cryomodule Milestones Long Lead Procurements start: 10/15/14 Cryomodule production start: 10/15/15 Cryomodule production complete: 11/12/18 Last cryomodule delivered to SLAC: 12/15/18 42

43 Milestone Schedule JLAB

44 DESY Visit: January, 2014 Goal: 1) Our first goal is to hear your comments on the LCLS-II baseline design. In the opinion of DESY / E-XFEL experts - is it a workable design? The baseline is derived almost entirely from TESLA / E-XFEL / ILC studies and DESY extensive experience and advice will be very important going forward. 2) we would like to re-start a practical, workable, collaborative arrangement between SLAC, other LCLS-II partner labs and DESY Go-To meeting teleconference link will be available 44

45 End 45