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SRF Development at daresbury laboratory A. Wheelhouse ASTeC, STFC Daresbury Laboratory

SRF Development at daresbury laboratory A. Wheelhouse ASTeC, STFC Daresbury Laboratory. 2 nd PASI Workshop, RAL 3 rd – 5 th April 2013. Outline. Mini PIPSS / IPS Programme Aims & Objectives Progress & Results SRF Cryomodule Development Aims & Objectives Progress Summary.

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SRF Development at daresbury laboratory A. Wheelhouse ASTeC, STFC Daresbury Laboratory

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  1. SRF Development at daresbury laboratoryA. WheelhouseASTeC, STFC Daresbury Laboratory 2nd PASI Workshop, RAL 3rd – 5th April 2013

  2. Outline • Mini PIPSS / IPS Programme • Aims & Objectives • Progress & Results • SRF Cryomodule Development • Aims & Objectives • Progress • Summary 4th April 2013 PASI Workshop A Wheelhouse

  3. Mini PIPSS & IPS Programme PASI Workshop A Wheelhouse

  4. Aims • The fundamental remit of the Mini PIPSS & IPS, Industry Partnership Schemes is to develop the capability of UK industry in the manufacturing of superconducting RF cavities • Mini PIPSS • Fabrication of a single cell niobium cavity (1-year) • IPS • Fabrication of a bulk niobium 9-cell accelerating structure (3-year) • Cell to cell alignment • Tuning robustness and uniformity • Tolerance management • Cleaning/processing compliance • RF surface integrity management • Technology directly applicable to future large scale accelerator facilities. • Opportunity for Daresbury Laboratory and Shakespeare Engineering Ltd to develop unique capabilities in the UK • Enable Shakespeare Engineering Ltd to exploit the large SRF commercial opportunity PASI Workshop A Wheelhouse

  5. Objectives • Mini PIPSS • Fabrication of a single cell TESLA SRF cavity • Acceleration gradient > 15 MV/m at a Qo better than 1 x 1010 • IPS • Fabrication of a 9-cell TESLA SRF cavity which will be qualified in 2 ways:- • Accelerating gradient > 20 MV/m at a Qo better than 1 x 1010after conventional Buffer Chemical Polishing (BCP) is performed • Accelerating gradient > 30 MV/m at a Qo better than 1 x 1010 when Electro-Polishing (EP) chemical processing is performed • Aim to provide a clear indication of Shakespeare’s capability and assist in qualifying them as a potential supplier PASI Workshop A Wheelhouse

  6. Cell and Beampipe Forming • Cavity half cells and beampipes fabricated by Shakespeare Engineering • Half cells pressed on a 60 t hydraulic press • Pressing performed in 3 operations • Beampipes were spun using a CNC spinning machine • Eliminates additional welded seam joint • Spinning of cones performed with intermediate heat-treatments • Beam tube finally formed on a mandrel • 3 single cell cavities welded at JLab 4th April 2013 PASI Workshop A Wheelhouse

  7. PIPSS #01 (JLab) Multipactor • Achieved 15.7 MV/m with a Q0 of 1.15 x 1010 Target • CW and pulsed conditioning • Gradient - 17.6 MV/m with a Q0 of 2.17 x 109 4th April 2013 PASI Workshop A Wheelhouse

  8. PIPSS #01 (JLab) • Additional BCP etch • Approximately 41µm removed 4th April 2013 PASI Workshop A Wheelhouse

  9. PIPSS #01 (JLab) • Vac furnace run at 600ºC for 10 hours • Plus an additional BCP etch • Approximately 28µm removed • Further high pressure rinses 4th April 2013 PASI Workshop A Wheelhouse

  10. PIPSS #01 (JLab) • Further high pressure rinses 4th April 2013 PASI Workshop A Wheelhouse

  11. PIPSS #02 (Daresbury) • Acid fume cupboard used to perform the BCP etch • Thickness removed measured on a sample piece which doubled as a stirrer • Acid temperature monitored • 85µm removed in 2 etch runs • Cavity turned up the other way for the 2nd run • HPR performed for 1 hour • Cavity sealed in a ISO4 class cleanroom PASI Workshop A Wheelhouse

  12. PIPSS #02 Evaluation • VTF manually filled from a 1000lt dewar • Reduced performance achieved on second cavity processed at DL • Ineffectivetemperature control on the BCP etch • Improvements to BCP processing is underway • Further testing to be performed PASI Workshop A Wheelhouse

  13. PIPSS #03 (FNAL) EB weld inspection FERMI Lab Standard Preparation • EB weld good • Some inclusions Electro-polishing monitoring 4th April 2013 PASI Workshop A Wheelhouse

  14. PIPSS #03 Tests FermiLab Tests • Cavity tested at 2K • Maximum accelerating gradient 25 MV/m with Q0=1.5x1010 • Gradient limited by a quench • First quench at 18 MV/m • Quenched twice at 21 MV/m • Finally quenched at 25 MV/m • Limited by repetitive quenches at 25 MV/m which showed no sign of conditioning after 20 mins • No field emission above background was observed • Some multipacting was noted at around 18 MV/m • Instabilities in Ptransmitted signal were observed • Common ILC-shape multipacting range • Multipacting processed • Successfully met target 4th April 2013 PASI Workshop A Wheelhouse

  15. PIPSS #03 Tests Target 4th April 2013 PASI Workshop A Wheelhouse

  16. PIPSS #03 - Further Qualification • Further processing performed • Cavity has been CBP • Removing ~180µm • Light 30µm electro-polish to remove a weld inclusion • Vacuum bake at 800ºC • Cavity to be tested 5/4/13 CBP Typical before and after CBP 4th April 2013 PASI Workshop A Wheelhouse

  17. IPS Programme • 3-year programme on-going • Cavity drawings complete • Tooling has been manufactured • Pressing trials being completed with Copper • Assessing repeatability and reproducibility • Niobium half cells to be pressed soon • Further beampipe spinning trials • Thicker sheets • SRF infrastructure development • Automated BCP process • Automated HPR • It is hoped that FNAL can continue to assist in qualifying Shakespeare with this structure. 9-cell cavity drawings BCP facility HPR stand 4th April 2013 PASI Workshop A Wheelhouse

  18. SRF Cryomodule Development ALICE 4th April 2013 PASI Workshop A Wheelhouse

  19. Aims & Objectives • To lead the design of a new, high current and world leading cryomodule. • To educate and demonstrate effective: • Processing, • Handling, • Assembly, • Testing, • QA processes. • To integrate the new cryomodule onto ALICE • Commission cryomodule + cryogenics systems • To validate cryomodule performance with beam 4th April 2013 PASI Workshop A Wheelhouse

  20. SRF Cryomodule • International collaboration initiated in early 2006: • ASTeC (STFC) • Cornell University • DESY • FZD-Rossendorf • LBNL • Stanford University • TRIUMF (2009) • Fabricate new cryomodule and validate with beam. • Dimensioned to fit on ALICE: • Same CM footprint • Same cryo/RF interconnects • ‘Plug Compatible’ Existing Cryomodule on ALICE ERL (New) Cryomodule 4th April 2013 PASI Workshop A Wheelhouse

  21. SRF Cryomodule Existing Cryomodule on ALICE ERL (New) Cryomodule 4th April 2013 PASI Workshop A Wheelhouse

  22. Coupler Conditioning • High power conditioning of the CPI input couplers: • Up to 30 kW (pulsed) • Up to 10 kW (CW) • For these tests, couplers water/air cooled only • No vacuum activity seen Pulsed Conditioning 4th April 2013 PASI Workshop A Wheelhouse

  23. Coupler Conditioning • High power conditioning of the CPI input couplers: • Up to 30 kW (pulsed) • Up to 10 kW (CW) • For these tests, couplers water/air cooled only • No vacuum activity seen CW Conditioning 4th April 2013 PASI Workshop A Wheelhouse

  24. Cryomodule Assembly HOM assembly µ metal installation Cavity wiring Cavity string 4th April 2013 PASI Workshop A Wheelhouse

  25. Cold Tests (Off-line) • Check the cryogenic performance • Understand the processes and establish commissioning and operating procedures • Validate instrumentation • Cavity frequency verification • Issue with tuner sticking had to be resolved • Identify and resolve any unknown issues • 80K tests successfully completed • Attempted to cool-down to 4K however: • Large temperature gradient between the two cavities • Helium reservoirs did not fill completely • Result of blockage between cavity bottom fill connection and excessive heat load at the input transfer line 4th April 2013 PASI Workshop A Wheelhouse

  26. Cryomodule Evaluation • Cryomodule installed and cooled to 2K • Optimisation presently being performed on the cryogenic system Evaluation Programme:- • Establish gradient and Q0 • Measure Lorentz force detuning at high gradient • Performance measurements with piezo tuners • Determine DLLRF control limitations wrtQext • Evaluate the effect of beam loading with DLLRF, piezo control for various Qextlevels under pulsed and CW conditions • Characterise cavities in CW mode at high gradient: • Evaluate thermal transients across cavity string and 2-phase line • Synergies with PXIE operational requirements to be evaluated Cryomodule installed on ALICE 4th April 2013 PASI Workshop A Wheelhouse

  27. Summary • Verified the fabrication of a single cell SRF cavity • 9-cell SRF cavity and infrastructure development progressing • UK SRF capability in a stronger position thanks to FNAL collaboration • Cavity string integrated into the cryomodule • Cryogenically commissioned cryomodule off-line • Cryomodule now installed in ALICE • Cryomodule characterisation about to commence 4th April 2013 PASI Workshop A Wheelhouse

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