SwissFEL Design and Status

Transcription

1 SwissFEL Design and Status Hans H. Braun Mini Workshop on Compact X ray Free electron Lasers Eastern Forum of Science and Technology Shanghai July 19, 2010

2 SwissFEL, the next large facility at PSI SwissFEL key parameters Wavelength range 1 Å 70 Å Pulse duration 1 fs 20 fs e Energy 5.8 GeV e Bunch charge pc Repetition rate 100 Hz

3 SwissFEL layout S band & X band C band C band C band 715 m Aramis: 1 7 Åhard X ray SASE FEL, In vacuum, planar undulators with variable gap. Athos: 7 70 Åsoft X ray FEL for SASE & Seeded operation. APPLE II undulators with variable gap and full polarization control. D Artagnan: FEL for wavelengths above Athos, seeded with an HHG source. Besides covering the longer wavelength range, the FEL is used as the initial stage of a High Gain Harmonic Generation (HGHG) with Athos as the final radiator.

4 SwissFEL Rational I Research capabilities of X ray FEL ideal complement for PSI s existing synchrotron light source and spallation neutron source research facilities European XFEL will not provide enough beam time for users in Europe Europe has with FLASH, FLASH II, FERMI@ELETTRA and maybe SPARX, NLS already good coverage for soft X ray FEL s hard X ray FEL

5 SwissFEL Rational II SwissFEL is build as a national facility in a small country Total cost have to fit in a limited financial frame λ = U K λ γ 2 λ ε N γ 4π ε N 1μm qb 2 [ nc] Lowest beam energy technically possible Small period undulators with low K values Low q B charge Normal conducting linac technology N γ

6 SwissFEL Rational III We want to build 1 st phase of SwissFEL Robust baseline design with components based on proven technologies. N & photon q B n& B γ Scientific focus rather on good time resolution than on photon hungry experiments Site constraints Power consumption < 5 MW Overall length < 900m

7 SwissFEL Science Case Magnetism: materials and processes for tomorrow s information technology Catalysis and solution chemistry: for a clean environment and a sustainable energy supply Coherent diffraction: flash photography of matter PDF of science report at Biochemistry: shedding light on the prpcesses of life Correlated electrons: the fascination of new materials

8 SwissFEL in comparison with the other hard X ray FEL projects Project LCLS, USA Start of operation April ! Beam energy GeV λ min Å SCSS, Japan European X FEL, Hamburg SwissFEL Observations SwissFEL is not a direct descendant of a Linear collider project SwissFEL has lowest beam energy Advantages: Compact and affordable on national scale Challenges : More stringent requirements for beam quality, mechanical and electronic tolerances

9 SwissFEL parameters e beam Design Parameters nominal operation modes long pulse short pulse upgrade operation mode ultra short pulse single bunch charge (pc) beam energy for 1 Å (GeV) core slice emittance (mm.mrad) projected emittance (mm.mrad) rms slice energy spread (kev) Relative energy spread (%) peak current at undulator (ka) bunch length rms (fs) bunch compression factor repetition rate (Hz) number of bunches / pulse bunch spacing (ns)

10 SwissFEL parameters photon beam FEL parameters ARAMIS (for 5.8GeV operation) nominal operation mode long pulse short pulse upgrade operation mode ultra short pulse undulator Period (mm) undulator Parameter energy Spread (kev) laser Wavelength (Å) maximum saturation length (m) saturation Pulse Energy (µj) effective Saturation Power (GW) rms photon pulse length at 1 Å (fs) number of photon at 1 Å ( 109) bandwidth (%) peak brightness (# photons mm 2 mrad 2 s 1 /0.1% bandwidth) average brightness (# photons mm 2 mrad 2 s 1 /0.1% bandwidth)

11 Time structure Aramis Athos Microbunches 28 ns 10 ms / 100 Hz 28 ns time Fast extraction at 3.4 GeV allows to serve 2 undulator lines simultaneously at full repetition rate

12 SwissFEL Milestones Gun laser MeV Injector facility 2014 Building completed Gun laser 2.1 GeV 3.4 GeV 5.8 GeV ARAMIS FEL 1-7 Å Exp1 Exp SwissFEL Phase I Accelerator and hard X ray FEL Laser pump Exp3 Gun laser 2.1 GeV 3.4 GeV 5.8 GeV ARAMIS FEL 1-7 Å Exp1 Exp SwissFEL Phase II Soft X ray FEL Seed laser ATHOS FEL 7 70 Å Exp1 Exp3 Exp2 Laser pump THz pump Exp3

13 SwissFEL Schedule

14 SwissFEL preparatory R&D, I 713 m Test of overall system performance in SwissFEL 250 MeV Injector

15 SwissFEL 250 MeV Injector Test Facility Beam got here

16 First Beam from RF Gun SwissFEL Injector March 12, 2010, ~12h10 Faraday cup signal YAG screen image Beam 100 pc Dark current

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18 goal: ε N <0.4μm for Q=200pC

19 First measurement of RF gun rms phase and amplitude jitter (each pointed is rms measured for 40 RF pulses) maximum phase jitter 0.019% maximum powerampl. jitter

20 Initial RF gun used for 250 MeV will be the CTF gun 5 (designed by M. Dehler and R. Bossart at CERN in the early nineties) designed to operate under heavy beam loading conditions Pumping T Tuner Faraday Cup Pickup (one per cell) Vacuum gauge Water connectors

21 New SwissFEL gun for test in 250 MeV injector 2012

22 X band harmonic cavity Collaboration between PSI - CERN - ELETTRA Klystron from SLAC Frequency (MHz) Number of cells 72 Cell phase advance 5/6π Iris aperture range (mm) Active length (m) 0.75 Nominal decelerating voltage (MV) 29 Wave guide TE 10 mode PSI: Cell procurements CERN: Assembly brazing ELETTRA: Wake analysis & support All: tuning & RF LLE analysis Electric short on one side Mode launcher (coupler) Matching cells TM 01 mode TM 01 mode HFFS simulated fields Axial signal output wave guides Cell 36 and 63 equipped with WG couplers for dipole mode monitoring

23 Wavelength tunable gun laser system Ti:sa oscillator 5 nj MHz booster amplifier stretcher IR Dazzler regenerative amplifier + Mazzler a few µj MHz 300 µj power amplifier dual stage up to 25 mj compressor BBO,type I BBO,type I THG SHG photon energy [ev] power density [arb.units] laser tuning range Δ E=330 mev wavelength [nm] nm, up to 900 µj 100 fs, 0.7% rms nm, up to 17 mj fs, 0.37% rms

24 Intrinsic Emittance versus Laser Wavelength Phys. Rev. Lett.104, (2010) Φ literature ~ Φ Fitted + 0.3eV

25 SwissFEL preparatory R&D, II 713 m Linear accelerator

26 Linac Cost vs. gradient S band with 45 MW klystron S band with 80MW klystron and C band with 50 MW klystron Cost S45 total S80 total C50 total S45 invest. S80 invest. C50 invest. S45 10y elec. S80 10y elec. C50 10y elec Gradient MV/m Main advantage of C band are savings in electricity consumption

27 Linear space requirements Active length S band acceleration Active length C band acceleration ARAMIS string of undulators Other beam line elements Photon beam transport Experiment halls 24 m 208 m 60 m 273 m 100 m 50 m Total facility length 715 m No strong motivation for very high gradients C band instead of S band is motivated by power consumption and number of RF stations!

28 SwissFEL Linac Module New high power teststand for linac module in prepration. Procurement of C band klystron in progress 27 x C band Klystron 5.7 GHz, 50 MW, 2.5 μs, 100 Hz 40 MW 2.5 μs 120 MW 0.5 μs SLED RF Pulse Kompressor 3 db 3 db 3 db 30 MW 30 MW 30 MW 30 MW 10 m For RF strucutres, 2 m each (5712 MHZ, 26 MV/m) Energy gain per module: 208 MeV

29 Solid state modulators tests in 250 MeV injector Klystron modulator unit Oil recovery tank acting as support Provisional reinforcement modulator support (installed January 13)

30 C band pulse compression with BOC Operating mode: E 18,1,1 Q: Coupling: 11 Ø = 475 mm BOC=Barrel Open Cavity CERN BOC (3 GHz)

31 Main linac C band RF structures PSI designs, builds and test 80cm prototype. Milestone: Complete first power test before end Based on this experience design and procurement strategy will be defined. More in Hanruedi s talk

32 SwissFEL Frequencies in MHz Injector Main linac S-Band X-Band (4 x S-band) C-Band (2 x S-band?) European American f b =142.8 most parts already delivered most parts on order, could still be changed requires development of klystron with PSI presently the only customer (21xf b ) (84xf b ) 5712 klystron available almost off the shelf Spring8, KEK, LNF are already customers SwissFEL frequencies 5712 (40xf b ) Common subharmonic 142.8MHz, mimimum bunch spacing 7 ns

33 SwissFEL preparatoy R&D, III 713 m Undulatoren

34 Undulator Strategy hard x-ray: soft x-ray: SPring-8 small period small gap in-vacuum undulators high harmonics variable polarization circular and inclined APPLE II standard, fixed gap BESSY Continuous development from SLS ID s U15, gap > 4mm, length 4m UE40, gap 6.5mm, length 4m Undulator Strategy for SwissFEL

35 Undulator Development U15 Conceptual design Thomas s presentation

36 SwissFEL Building Layout 715m

37 Linac cross section 4500 mm 3500 mm 4000 mm 9600 mm

38 SwissFEL site and situation

39 1 RF Module Loading Zone ATHOS Experiments Linac m e - gun Injector 98 m Linac m Linac m ATHOS Undulators ARAMIS Experiments ARAMIS Undulators 97 m ARAMIS Collimator (51 m)

40 Power consumption

41 SwissFEL CDR Official publication 24 August 2010 for Inauguration ceremony of 250 MeV Injector Draft available from or

42 Thank you for your attention!