Accelerator RFQ system Anne-Catherine CHAUVEAU for the ESS RFQ Team at CEA Saclay April, 2016

RFQ system Overview 2 Tuners x60 Cooling connector x80 RF Couplers x2 Pumping system (x36) Pick-ups (x28) 5 sections Tuned and conditioned RFQ on its support Partial RF distribution system Water cooling system MAIN GOALS of the RFQ :  Bunch the proton beam at the frequency of MHz  Accelerate the beam from the exit of the source at 75 keV up to 3.6 MeV  Provide optical characteristics to the beam in order to avoid losses at higher energy. Planning  Start date: Kick Off “Warm Linac Internal Review  Completion date: Ready for transportation to ESS Lund  Completion date: Formal transfer after conditioning operations in ESS tunnel

RFQ system Schedule 3 Coupler test and conditioning Test cavity body leak test Coupler manufacturing Coupler tender Test cavity assembly Test cavity and auxiliaries Manuf./brazing PI tender Aux. copper manufacturing Tuner tender Tuner Manuf. Poles copper manufacturing HIP RFQ tender Section 1 Machining Section 1 Ass./Braz De-ass +packing Process Qualification RFQ ass. Sec 2 Ass.Braz. Sec 2 Mach. Tuner proto manufacturing Section 1 assembly. IO plates tender IO plates finger brazing Re-Ass. Transport Condition. SAR2 16/07/1 8 RF Test Sec 5 Ass.Braz Sec 5 Mach. Sec 4 Ass.Braz Sec 4 Mach. Sec 3 Ass.Braz Sec 3 Mach. Section 1&2 assembly. Section 2&3 assembly. Section 3&4 assembly. Sec 5 Ass Cooling system tender SKID syst manuf. SKID syst tunnel inst. SKID syst transport SKID syst packing PLC progra mming PLC manufac turing PLC order IO plates manufacturing SAR1 13/03/18

RFQ Technical performances 4 To reach these performances, ESS and CEA have already put up the followings: Detailed Beam analysis study and simulations Detailed RF design studies and simulations Detailed thermal aspect study and simulations Detailed mechanical studies Detailed cooling system analysis Complete requirement definition Permanent interface definition and follow-up Remaining tasks to fulfill these requirements: Close follow up of all manufacturer process and progress Several measurements and leak tests throughout RFQ manufacturing (Bead-Pull for voltage law and 3D measurements) Main requirements: Other requirements:  L3  L4 Electromagnetic Resonators  L4 Vacuum  L4 WTR (Water)  L4 RFDS (RF Distribution System)  L4 LLRF (Low Level RF)  L4 CIC (Control command)  Alignment

RFQ System Selected technologies 5 Deliverables Tuned and conditioned RFQ on its support, RF distribution system, water cooling skid RF design four-vane structure, naturally stable single segment tunable devices: end rods, vacuum ports, slug tuners, RF couplers Fabrication of RFQ modules 4 electrodes with modulations and apertures for ancillaries one step of copper-copper brazing in vertical position (IPHI) 5 modules with length < 1 m in agreement with demonstrated technology Brazed vacuum ports avoid machining of grids in the vanes accurately positioned after electromagnetic measurements, prior to braze (Linac4, IPHI) RF couplers loops offer less power dissipation and voltage ripple (Spiral2) small coaxial window standard tuner port allows coupling adjustment at final Q Adjustable slug tuners performances achieved at last tuning step are saved under vacuum allow for last minute corrections, after transport for instance no delay required for machining after last tuning step

RFQ System Selected technologies 6 RF distribution one Power divider, one power load and two feeders loops in 90° quadrants tuned to minimize voltage perturbation phasing trombone to minimize reflection coefficient Voltage profile monitoring 5  4 pick-ups will allow reconstruction of voltage profile check RFQ voltage integrity vs. time voltage profile corrections are possible to some extent Water cooling dedicated skid with four independent circuits independent control of frequency and voltage function eventually useful for voltage corrections Transition (with SMS connector) Reflectometer Coupler Flexible waveguide Spiral2 RFQ untuned Spiral2 RFQ: tuned with copper slugs

RFQ system Integration and Verification Plan 7 RFQ Test cavity ports are identical to RFQ ports and used as ports prototypes Brazing and drilling mock-ups for manufacturer qualification Vacuum and water leak tests done several times during processing Bead-Pull and 3D measurements after poles assembly and before and after cu-cu brazing Sections tested at Saclay in parallel with other sections manufacturing Assembly process partially validated early at Saclay Pre-RF tuning of the RFQ done in Saclay prior shipping to Lund RF loop (coupler = window + loop) Several partial Mock-ups for manufacturer qualification (ceramic brazing and TiN coating) Leak test and 3D measurements during manufacturing steps. Low power RF tests (to check windows manufacturing) at Saclay with the test cavity Adjustable slug tuners One innovative prototype ordered prior to main tuner tenders (back-up solution is available) Bellow brazing qualification of manufacturer Verification of behavior under pressure on the test cavity 3D measurements, leak tests, RF tests with test cavity Cooling system Factory FAT using simulated load Test cavity: 2 RF power loops, 1 vacuum port, 1 tuner port Test cavity test stand Bead-Pull measurement

RFQ Organization at CEA partner lab 8 Project Management Office is in charge of the organisation of the CEA-ESSI project and manages the interfaces with ESS management as well as Management plan, configuration management, project Quality management, performance and progress dashboard follow- up and non conformity management. RFQ WU lead by Bruno Pottin is responsible of:  The Design  The development  The realisation and manufacturing  And the performance validations of the RFQ system Under the supervision of the ESS Project Management Office of CEA/IRFU

RFQ Budget and cost-book 9

RFQ system Major Procurements 10 TUNER COUPLERS TEST CAVITY and AUXILIARIES PROTOTYPING COUPLER CONDITIONING COPPER RFQ MANUFACTURING RFQ ASSEMBLY and TESTS RFQ RE-ASSEMBLY and CONDITIONING RFQ PACKING and TRANSPORT MPP planning is more than 200 lines Manufacturer’s planning awaits confirmation | PAGE 10 Delivery to Lund due 13/03/18 Formal Handover due 16/07/18 Assembly in Saclay will start in parallel with sections manufacturing

RFQ system Top risks 11 No “Very High” level risks after mitigation  Main risks linked to time schedule as it contains no margin and is very tight Risk that manufacturers do not succeed the 20 months challenge Risk of overcost due to late validations in the tunnel instead of Saclay (First complete test of the RFQ will be done in the tunnel. Only partial validations are done in Saclay before delivery to ESS) -> Maximum validations done in Saclay Risk on tenders meeting points especially auxiliaries Vs RFQ cavity -> Tight tracking of manufacturer progress  Risk of overcost due to request for short manufacturing delays  High technical risks on coupler manufacturing and on coupler not reaching requested power because coupler is very complex and power requirement is very high -> Manufacturer mock-up qualifications and 1 spare coupler

Next Six Months Schedule signature All main tenders should be signed shortly (RFQ, test cavity and auxiliaries and couplers) Focus is now moved to supports and assembly tools Cooling system specification done at 95% and tender started Tuner prototype due before end of april Test and validation specifications 12

RFQ system Summary 13 Schedule is very tight. Strong tendering activity made difficult because of short schedule and ESS transformation into an ERIC Very high level of technology for RFQ and RF couplers But still on track for the moment