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JLab ERL Possibilities

JLab ERL Possibilities

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JLab ERL Possibilities

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  1. JLab ERL Possibilities

  2. JLab ERLs • JLab uniquely positioned to contribute to ERL technology • SRF center of excellence • Large scale SRF recirculator • High power SRF-ER FEL driver • Extensive design, construction, & operations experience base • Experience with high brightness sources • High power SRF injector expertise • Can identify numerous ERL-related projects • High current gun • High power injector • High current recirculator testing

  3. ERL-Related Projects • Can identify numerous ERL-related projects • tests with IR Demo • test concepts, software, etc in manageably small system • high current gun • high power injector • high current recirculator testing in FEL upgrade • 10 mA initially (1-2 yrs) • 100 mA with AES gun (3-4 yrs) • energy recovery, current doubling, beam physics (RF, CSR, BBU, space charge) tests • CEBAF-ER • CEBAF-ER/CD • GERBAL • JERBAL

  4. ITV1F02 Pass 1 Pass 2 Pass 3 ITV2F00 Pass 1 Pass 2 ITV4F05 Pass 1 Pass 2 ITV1G02 Pass 3

  5. CEBAF-ER • Can easily & non-invasively perform 1st large scale test of energy recovery using CEBAF • requires 8 FEL dipoles (4 DW, 4 GW), power supplies, stands • build half-wavelength chicane at end of north linac, extraction chicane at end of south (requires construction of 2 vacuum chambers, installation) • accelerate 1 pass up, recover 1 pass down • “turn chicane off & download standard settings” to return to NP ops. • Big return for small investment

  6. CEBAF-ER concept • By “borrowing” FEL DW & GW dipoles can build phase delay & extraction chicanes to create (noninvasive) CEBAF-ER and CEBAF-ER/CD • Chicanes limited to single pass energies • Install after linacs • Use FEL stands & power supplies • Simplifies geometry, beam handling

  7. CEBAF-ER optics • Beam transport constraints include the all typical ones as well as the commonality of transport during energy recovery

  8. CEBAF-ER/CD • Can current-double by putting a quarter wavelength chicane after the south linac • (actually, two 1/8th wavelength GW chicanes (BL limited)) • Must tinker with injector/linac energies and east arc excitations to get coasting beam into east S/R acceptances • Ei=65 MeV, EN=ES=234 MeV, use arcs 5 and 9 • or use asymmetric linacs (prelude to JERBAL): Ei=65 MeV, EN=351 MeV, ES=117 MeV, use arcs 7, 9 and 3 • Helps if commonality of transport is a problem – gives independent knobs • Demo experience suggests handling multiple beams in common structure may require some delicacy in sorting out the steering and focusing. Of course, CEBAF linacs do this daily!!!

  9. low energy east arc full energy west arc full energy east arc full energy west arc low energy east arc CEBAF-ER/CDb optics • Balanced linac solution, 65/234/234, arcs 5 and 9, common transport from injection to dump • Some mismatch evident on later passes; will propagate thru arcs & may be fussy…

  10. Multipass CEBAF-ER • A prelude to JERBAL • Requires more robust chicanery (in arcs rather than at ends of linac) • Steering & matching of multiple beams in common transport structures a concern

  11. A Final Comment on Commonality • Mismatch issues arise in CEBAF-ER because blank zones in linacs generate symmetry violations – the machine doesn’t reflect around the center of the highest energy transport • Can avoid this in future machines (to within error tolerances!) by using modularized reflectively symmetric optics – making the linacs symmetric up and down & matching arcs to reflectively symmetric envelopes

  12. GERBAL • Generic Energy-Recovering Bisected Asymmetric Linacs • Energy Recovering – for sure! • Bisected – recirculate high energy beam to high energy linac to improve focusing to energy match • Asymmetric Linacs– low energy linac short, high energy linac long • Short low energy linac reduces mismatch of higher passes, improves focusing/energy match, dynamic range • “Generic” – a design initiative: study general behavior without reference to specific parameter sets • Establish • optimal injection:final energy ratios • pass count • Linac length • SRF parameters

  13. JERBAL • Jlab Energy-Recovering Bisected Asymmetric Linacs • SR source • Parameters to meet user demands • Based on JLab technology, experience

  14. An Energy-Recovered Linac for SR • The “JLab Energy-Recovering Bisected Asymmetric Linacs”, or JERBAL, is a 10 GeV driver for SR production

  15. Photon Farm (9.6 GeV beam) 1.2 GeV Linac 1.2 GeV accel. 1.2 GeV ER 10 MeV Injector 1 MW Dump 4.8 GeV ER 4.8 GeV accel. 6.0 GeV accel. 6.0 GeV ER 3.6 GeV Linac recirc recirc recirc recirc recirc recirc recirc JERBAL, cont. • Machine configuration: • Transverse optics

  16. JERBAL, cont. • Site plan

  17. Directions • FELs can in principle provide ERL-related opportunities here for some time • Test-bed for high current sources, injectors, tractably-scoped technology tests & physics initiatives (CSR, BBU, wakefield, novel photon sources, space charge, etc) • CEBAF presents possibilities • CEBAF-ER in short term • CEBAF-ER/CD with some additional work • CASA resouces well matched to “GERBAL” investigations • General broad-scope, high level system studies • Specific collaborations (Cornell, BNL, LBNL) • JLab – potential future as a multipurpose facility – with, e.g., JERBAL as a user center