1 / 16

A Plan f or the Development of Superconducting Undulator Prototypes for LCLS-II and Future FELS

P. Emma, N. Holtkamp, H.-D. Nuhn, SLAC C . Doose, J. Fuerst, Q. Hasse, Y. Ivanyushenkov, M . Kasa, G. Pile, E. Trakhtenberg, E. Gluskin, ANL D . Arbelaez, J. Corlett, S. Myers, S. Prestemon , R. Schlueter, LBNL.

zubeda
Download Presentation

A Plan f or the Development of Superconducting Undulator Prototypes for LCLS-II and Future FELS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. P. Emma, N. Holtkamp, H.-D. Nuhn, SLAC C. Doose, J. Fuerst, Q. Hasse, Y. Ivanyushenkov, M. Kasa, G. Pile, E. Trakhtenberg, E. Gluskin, ANL D. Arbelaez, J. Corlett, S. Myers, S. Prestemon, R. Schlueter, LBNL A Plan for the Development of Superconducting Undulator Prototypes for LCLS-II and Future FELS P. Emma, …for the SCU R&D collaboration: ANL, LBNL, SLAC August 28, 2014

  2. Kicking the Can Down the Road (SCU’s)… • Proposed by E. Gluskin & N. Vinokurov in 1999 for LCLS-I“not ready for SCU” (15yrsago!) • Propose to re-design LCLS-II undulator and greatly improve performance (1 TW & 7 keV)? • SCU’s operating in ANKA (2005) & APS (2013) right now • Greatest un-tapped potential available for FEL performance

  3. Superconducting Undulator Motivation Advantages of an SCU: • Higher magnetic fields allow superior FEL performance. • No permanent-magnetic material to be damaged by radiation  longer life & smaller gaps. • Reduced (?) resistive wakefield with cold bore (preliminary). • Much lower vacuum pressure, which limits gas scattering. • Smaller footprint and simpler K-control than typical, massive adjustable-gap PMU. • Easily oriented for vertical polarization*. SCU’s need practical development… * Vertical polarization allows efficient x-ray transport in horizontal deflections

  4. SCU’s Provide Much Higher Fields than PMUs SCU much higher field for given period and gap Nb3Sn NbTi LCLS-II SCU In-Vac. PMU PMU LCLS-II PMU: lu = 26 mm Bpk = 1.0 T gm= 7.3 mm 5-mm vac. gap for all (7.3-mm mag. gap) In-Vacsame vac. gap (5.3-mm mag. gap)

  5. Und. Length vs Upper-limit Photon Energy (LCLS-II) 2-m segments & 0.7-m breaks In-Vac-5 In-Vac-5 NbTi-5 Nb3Sn-5 Lower-limit photon energy = 1.5 keV (at 4 GeV) in all cases Nb3Sn-5 In-Vac-5 NbTi-5 PMU-5 Self Seeded  4.8 keV Limit 145 m 145 m/1.5 In-Vac-5 NbTi-5 7.6 keV 6.5 keV NbTi-4 In-Vac-4 Nb3Sn-4 PMU-4 lu = 25.8, 24.4 mm, 22.9, 21.3 mm, 19.3, 18.4,mm, 17.7, 16.8 mm Kmin = 0.66, 0.64, 0.65, 0.65, 0.65, 0.64, 0.63, 0.63 Kmax= 2.4, 2.5, 2.6, 2.7, 2.9, 3.0, 3.1, 3.2 Bmax < 2.1 T Includes breaks & 20% length margin for SASE saturation “5” labels (PMU-5) have 5-mm vac. gap; “4” have 4-mm “In-Vac” has same vac. gap, but 2-mm smaller mag. gap

  6. “TW-FEL” with SCU & Cu-Linac (LCLS-II) Step-wise tapered undulators (20%) 1.6 TW (4 keV) 4 GeV (1 MHz) 3-15 GeV (120 Hz)  1 MHz SXU SC-Linac Cu-Linac HXU Choose und. segment length (2 m) similar to gain length (1 m) to maximize peak power switch SCU 120 Hz Self-seeding monochromator C. Emma, C. Pellegrini, Z. Huang

  7. Resistive-wall Wake of Cold-bore Undulator 4 GeV (Gaussian bunch) Rectangular chamber 4-mm chamber gap height 9mm rms bunch length L = 100 m, ~4K 2r 0.08% Resistive-wall wakefield due to anomalous skin effect at ~4 K Based on work by B. Podobedov, PRSTAB, 12, 044401 (2009), and new G. Stupakov, K. Bane model (preliminary)

  8. SCU R&D Plan • ANL… • Build 2-m test cryostat (existing design) • Build & test 1.5-m long NbTi prototype und. (lu 21 mm) • LBNL… • Build & test 1.5-m long Nb3Sn prototype und. (lu 19 mm) • Develop meas. & tuning schemes (small tuning cryostat) • All Labs… • Develop field measurement and correction techniques • Demonstrate predicted field, field quality, end corrections, and cold-mass integration into cryostat • Develop conceptual design for full-length SCU in LCLS-II • Goal: By July 2015, deliver 2 fully functional, 1.5-m long, SCU prototypes meeting LCLS-II HXU spec’s

  9. (Nb3Sn) Prototype Magnet - LBNL Nb3Sn to NbTi joints at end of undulator gm= 8 mm lu= 19 mm Wire Pocket (8×7) Nb3Sn Electron Beam Nb3Sn 0.6-mm diam. wire, 60-mm braid insulation Bpk= 1.86 T IEEE Trans. on App. Supercon., Vol. 17, No. 2, June 2007 , pp. 1243-1246. Load Lines Critical Current, Ic 8×5 On-Axis Field 8×7 Peak Conductor Field Design Point 8×9 6-period prototype (Nb3Sn) built at LBNL in 2006 - reached 97% of current (lu= 14.5 mm).

  10. Undulator Assembly Components - LBNL Cooling plates are separate to allow Nb3Sn heat processing (~650 C)

  11. SCU Tape Phase Correction Scheme - LBNL Single-turn correction coils placed on each side of vacuum chamber Needs demo May not be necessary? single turn correction coils current (< 100 A) heater switches S. Prestemon, D. Arbelaez, LBNL

  12. Prototype Magnet - ANL (NbTi) Wire pocket (53 turns) lu= 21 mm gm= 8 mm NbTi e- 0.7-mm diam. Supercon NbTi SC wire Bpk= 1.66 T Lower risk, but less field Short test cores to verify tolerances and recent 1.1-m SCU1 now powered Load Lines Ic curve On-Axis Field 745 A @3.8 T Recent, very encouraging SCU1 results! (not shown) (1.66 T, 600 A, @80% Ic) Peak Cond. Field (3.35 T @80% Ic)

  13. End-coil Winding Scheme - ANL End-Terminations and Field Correctors 0 ,51,100 Amp (Measurements) Precision cores & precision winding! Tolerance: 40 G-cm “SCU” being wound on bench 15/15 15/38 53 energized by main supply (600 A) winding pack front face Fully wound 1.1-m half-magnet energized by separate supply (70 A) shows 11 complete coil packages

  14. ANL 2-m Cryostat (to test both magnets) 2-m long cryostat; 4 cryo- coolers; Loss-free He system • Existing 2-m cryostat (4K) at APS • Experience with SCU’s at APS • Each magnet to be tested in this cryostat 4 cryo- coolers 100-l LHe vessel magnet & beam pipe

  15. SCU System Concept for LCLS-II HXU 0.5-m cold breaks 2-m long segments (+quad+BPM+PS) lu = 17-19 mm, Vacuum gap = 4-5 mm 5-m cryostats 500-W cryo-plant at 4 K Joel Fuerst, ANL

  16. Summary • SCU technology promises a potential leap in FEL performance – needs development now • LCLS-II HXU can be extended to 7+ keV (1 MHz) and 1 TW (120 Hz) using the same SCU • R&D is underway – re-baseline of LCLS-II is possible, but depends on R&D and LCLS-II project schedule 1 MHz, 1 - 7+ keV  1 MHz 0.2-1.3 keV SXU SC-Linac or Cu-Linac HXU SCU switch 120 Hz, 1 - 25 keV, 1 TW (4 keV) 120 Hz Thanks to the SCU team: P.E., N. Holtkamp, H.-D. Nuhn, SLAC; C. Doose, J. Fuerst, Q. Hasse, Y. Ivanyushenkov, M. Kasa, G. Pile, E. Trakhtenberg, E. Gluskin, ANL; D. Arbelaez, J. Corlett, S. Myers, S. Prestemon, R. Schlueter, LBNL

More Related