ELECTRON BEAM DRIVEN WAKEFIELD GENERATION AT THE AWA
ELECTRON BEAM DRIVEN WAKEFIELD GENERATION AT THE AWA FACILITY MANOEL CONDE EAAC Sept. 2019
AWA R&D PROGRAM MISSION Developing the science and technology of electron beam generation, manipulation and acceleration, for beam-driven wakefield acceleration and other applications. Research Focus • High intensity electron beam • Novel cathodes and RF guns • Electron beam driven wakefield acceleration o Structure Wakefield Acceleration (SWFA) o Plasma Wakefield Acceleration (PWFA) • Advanced Structures • High power RF generation • Phase space manipulation o Bunch shaping o Bunch compression • Novel applications 2 Electron Sources AAC Beam Physics
AWA ORGANIZATION CHART Kawtar Hafidi – HEP Interim Division Director Salman Habib – Deputy Division Director Nancy Rezek Administrative Assistant Norm Rendon Financial Officer Leon Reed Safety Coordinator Deputy Group Leader Manoel Conde Controls & RF Systems Mech. & Civil Eng. Photocathode Laser Electron Sources Beam Physics Advanced Accelerator Concepts Wanming Liu Scott Doran John Power Eric Wisniewski Gwanghui Ha Jiahang Shao 3
ADDITIONAL PERSONNEL Making things work Guest scientists: • • Sasha Zholents (ANL - APS) Chunguang Jing (Euclid Techlabs) Sergey Antipov (Euclid Techlabs) Philippe Piot (Northern Illinois University & ANL) Charles Whiteford Graduate students: • • Jimin Seok (Ulsan National Institute of Science and Technology, Korea) Maomao Peng (Tsinghua University, China) Tianzhe Xu (Northern Illinois University) Mitchell Schneider (Michigan State University)
OUR COLLABORATORS Omega-P 5
STRUCTURE-BASED WAKEFIELD ACCELERATION (SWFA) Several variations of scheme, geometry, frequency, material. Two-Beam Acceleration (TBA) Collinear Wakefield Acceleration (CWA) main beam drive beam main beam • • • Geometry: cylindrical, planar, or novel (PBG, metamaterial, etc) Frequency: typically from 10 GHz to 1 THz Material: metallic, dielectric, hybrid 6 Goals: • high efficiency • high gradient • beam quality
ARGONNE FLEXIBLE LINEAR COLLIDER 3 Te. V 30 MW beam power TBA 18 km 7. 5 km linac • Short rf pulse (20 ns) for high gradient (e+ e- 200 Me. V/m of effective gradient) • Modular design easily staged • Wall plug efficiency (~10%) 7
BEAMLINES AND TEST-STANDS 20 MW RF power station RF gun studies and conditioning ACT Cathode studies Breakdown studies drive beam witness beam Witness beamline 4 – 15 Me. V 0. 001 – 20 n. C Drive beamline 8 – 70 Me. V 0. 001 – 100 n. C (single bunch) Bunch trains (up to 32 bunches with 600 n. C total) Unique capabilities of AWA: • • • Two independent linacs Emittance exchange beamline Wide range of bunch charge (highest) & flexibility 8 Ideal test-stand for beam driven wakefield studies
TWO-BEAM-ACCELERATOR & STAGING Staging accelerating X-band 11. 7 GHz structures power extractor Two Drive trains to successively accelerate witness bunch with preserved its beam quality accelerator 70 Me. V/m in two stages 20 n. C/bunch, 16 bunches, 320 n. C total 150 Me. V/m in one stage 45 n. C/bunch, 8 bunches, 360 n. C total 300 MW in one stage 54 n. C/bunch, 8 bunches, 430 n. C total C. Jing, et al. , NIMA 898, 72 -76 (2018)
COLLINEAR WAKEFIELD ACCELERATION High gradient acceleration D. Wang, et al. , PRL 116, 054801 (2016) W-band 91 GHz structure Peak gradient 85 Me. V/m, 3 n. C/bunch, 4 bunches, 12 n. C total High transformer ratio 100 GHz slab structure High charge shaping with EEX Q. Gao, et al. , PRL 120, 114801 (2018) TR~5, 20 n. C from gun, 2 n. C after EEX
HIGH POWER GENERATION BY AN X-BAND DIELECTRIC-LOADED POWER EXTRACTOR - Maximum 200 MW rf power measured with 360 n. C 8 -bunc train, could be underestimated - No sign of breakdown nor multipacting - Good agreement between simulation and cold test result - Future structure optimized for GW power 11 J. Shao et al. , submitted to PRAB
HIGH POWER GENERATION BY AN X-BAND METALLIC POWER EXTRACTOR - Maximum 300 MW measured with 500 n. C 8 -bunch train Tunable structure - Large discrepancy between simulation and experiment observed at the forward coupler - Good agreement at the backward coupler - Possibly caused by multipacting inside the rf pickup - Six newly-designed direction coupler fabricated - Experiment to be re-conducted, aiming for 500 MW power 12 M. Peng, et al. , IPAC 2018
HIGH POWER TEST OF X-BAND METAMATERIAL POWER EXTRACTORS (PHASE I AND II) - Reverse Cherenkov radiation - Rugged all-metal structure - Enhanced beam-wave interaction Phase I: Short structure @ 11. 42 GHz - Reverse CR demonstrated - 80 MW rf power Phase II: Long structure @ 11. 7 GHz - 380 MW rf power (Preliminary results to be confirmed) 13 X. Lu et al. , PRL 122, 014801, 2019
HIGH POWER TEST OF AN X-BAND PHOTONIC BAND-GAP STRUCTURE Experiment I: HOM suppression Experiment II: collinear wakefield acceleration - Up to 6. 3 n. C single bunch - HOM damping successfully demonstrated - Two drive bunches, up to 45 n. C - Two low charge witness bunches - Maximum gradient of 35 MV/m E. Simakov, et al. , PRL 116, 064801, 2016 J. Upadhyay, in preparation
PWFA High transformer ratio 10 -12 n. C from gun, 1. 5 -2 n. C after EEX Hollow cathode arc plasma source R. Roussel, et al. , to be submitted
500 MEV SHORT PULSE TBA DEMONSTRATOR Proposed layout 70 Me. V drive beam 2 x 8 -bunch trains 40 n. C/bunch, 640 n. C total 15 Me. V main beam Single bunch 0. 1 -3 n. C - 2 stages, 2 pairs of structures per stage - Drive beam: decelerated from 70 to ~20 Me. V - Main beam: accelerated from 15 to ~500 Me. V Drive beam Waveguide delay 26 GHz dielectric structures Copper Load Phase shifter Drive beam switch Dielectric Main beam J. Shao, et al. , in Proceedings of NAPAC 2019
COLLINEAR WAKEFIELD ACCELERATION (FEL) Proposed CWA module for multi-beamline high repetition XFEL Doorstep shape drive beam, 10 n. C, TR>5 220 GHz corrugated waveguide structure with permanent magnet quadrupole A. Zholents, et al. , in Proceedings of IPAC 2018
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