PXIE RFQ Design Overview Derun Li for PXIE RFQ Design Team Center for Beam Physics Accelerator and Fusion Research Division Lawrence Berkeley National Laboratory April 12, 2012 PXIE RFQ Design LBNL

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Acknowledgements Matt Hoff, Qing Ji, Andrew Lambert, John Staples, Thomas Schenkel, Steve Virostek Lawrence Berkeley National Laboratory Chuan Zhang Institute for Applied Physics, Goethe University Frankfurt, Germany Gennady Romanov, Sergei Nagaitsev and … Fermi National Accelerator Laboratory Chinese ADS Team Members at Institute of Modern Physics, Lanzhou, China 2

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Outline PXIE RFQ Design Overview LBNL RFQ experience Summary of PXIE RFQ design status PXIE RFQ design details: Beam dynamics and error analysis RF structure simulation studies Engineering Thermal, RF and mechanical analyses Fabrication tests Upcoming tasks and plans

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Presentations at the Review PXIE RFQ design overview Beam dynamics design and error analysis John Staples RFQ RF structure simulation studies G. Romanov RFQ engineering design overview S. Virostek Detailed Mechanical Design M. Hoff RFQ thermal and stress analysis A. Lambert

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 LBNL RFQ Experience 5 RFQ1 - Bevatron RFQ3 – BNL Injector RFQ2 – CERN RFQ4 – LBNL Proton RFQ5 – SNS (PISL) RFQ3 (BNL) and RFQ5 (SNS) are operational currently; ADNS and spare SNS RFQ designs recently; PXIE RFQ is the first NC CW RFQ that LBNL designs and builds.

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Summary of PXIE RFQ Design Status Beam dynamics design completed, the design meets PXIE requirements: – – High acceptance from 1 to 15 mA – – Small emittance growth due to (large) errors Beam dynamics design frozen Error analysis completed RF design completed (G. Romanov’s presentation) – – RF simulation studies include: pi-mode rods, tuners, radial matcher and cut-backs – – Field distribution and dipole mode separation:  20 MHz Engineering design nearly complete Thermal and stress analysis nearly complete Fabrication tests started. 6

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 PXIE RFQ Mechanical Design Summary of PXIE RFQ design: o o RFQ: 4.45 meters long consists of four modules; o o 32 Pi-mode stabilization rods; o o 2 RF power couplers; o o 80 slug-tuners (20 per module); o o 48 RF probes; o o 8 vacuum pumping ports. 7

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 PXIE RFQ Beam Dynamics Design Beam distribution derived from ion source emittance measurements; Transmission: 99.8 % at 5 mA; 99.8 % at 5 mA; Transverse output emittance: 0.15 pi mm-mrad 0.15 pi mm-mrad Longitudinal emittance: 0.64 keV-nsec 0.64 keV-nsec From 1-15 mA

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 RF Simulation Studies of PXIE RFQ 9 ParametersPXIE-T Frequency, MHz Frequency of dipole mode, MHz Q factor14660 Q factor drop due to everything, %-14.7 Power loss per cut-back, W (In/Out)336/389 Max power loss density at cut-back, W/cm Total power loss, kW73.8 H, mm SectionPower(kW)Walls29.5 Vanes31 Input cut-backs 1.34 Output cut-backs 1.56 Pi-mode rods (32) 5.53 Tuners (80) 4.79 Sub-total73.72 Beam power at 5 mA 10.5 Total84.22

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Engineering Design Develop the PXIE design based on past LBNL RFQ experience Use proven, low risk techniques from pervious RFQ designs –Four vane copper-to-copper braze –Fly cut modulated vane tips –Brazed, water cooled pi-mode rods –Low profile, bolted module joints –Removable fixed slug tuners –Eliminated high risk features

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 PXIE RFQ Design Features All OFHC copper body machined from solid billets 4-vane cavity structure with fly cut modulated vane tips Four  1.12 m long cavity modules with bolted joints MHz frequency Total length: 4.46 m Pi-mode rods for mode stabilization Distributed fixed slug tuners CAD model of assembled 4-module PXIE RFQ design concept

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Thermal and Mechanical Analyses Numerous engineering analyses carried for design validation Cavity body and vane cutback thermo-mechanical analyses using an ANSYS RF/thermal/structural model Stress analysis using converted ANSYS thermal model Water temperature tuning analysis using a separate ANSYS model Calculation of area properties for body stiffness analysis Sub-model of the cutback region (RF, thermal, displacement)

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Fabrication Tests Vane cutting tool test Full length vane fabrication test Vane braze test

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Additional Engineering Tasks  Carry out fabrication tests (at LBNL and IMP-Lanzhou) Write engineering notes describing the test procedures Procure all necessary material  Perform additional analyses Vacuum system analysis Final RFQ support points – stress and deflection analysis  Complete final version of the RFQ 3D CAD model (close)  Generate complete set of multi-step fabrication drawings  Write a detailed engineering notes to document the final RFQ design and the results of the analyses

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Remaining Tasks and Plans – – RF power coupler: Modify/update MICE RF coupler or design a new RF coupler – – Formed cutter testing in progress at LBNL – – Procurement of copper for the fabrication tests and RFQ – – Complete the fabrication tests Visit and identify vendors for e-beam welding and RFQ brazing – – Fabrication drawings to be completed by FY12 – – Finish engineering analysis: thermal, vacuum and support structure: stress and deflection – – RFQ fabrication readiness review: October 2012 – – Begin PXIE RFQ fabrication: November

Derun Li: PXIE RFQ Design Overview PXIE RFQ Design Review, Berkeley, CA April 12, 2012 Remaining Tasks and Plans An additional fabrication test of a short RFQ module at IMP-Lanzhou: – – Include all features of PXIE/IMP RFQ – – Low power RF measurements to further bench-mark RF simulation results CST MWS SLAC ACE3P 16