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Light Sources and Future Prospects

Light Sources and Future Prospects. R. Bartolini Diamond Light Source Ltd and John Adams Institute, University of Oxford. IoP NPPD Glasgow, 06 April 2011. Outline. Introduction synchrotron radiation properties and users’ requirements 3 rd generation light sources

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Light Sources and Future Prospects

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  1. Light Sources and Future Prospects R. Bartolini Diamond Light Source Ltd and John Adams Institute, University of Oxford IoP NPPD Glasgow, 06 April 2011

  2. Outline • Introduction • synchrotron radiation properties and users’ requirements • 3rd generation light sources • performance, trends and limitations • 4th generation light sources • AP and FEL challenges and enabling R&D • beyond 4th generation • Laser plasma accelerators driven light sources • Conclusions IoP NPPD Glasgow, 06 April 2011

  3. Synchrotron radiation properties Broad Spectrum which covers from microwaves to hard X-rays (tunable with IDs) High Flux: high intensity photon beam High Brilliance (Spectral Brightness): highly collimated photon beam generated by a small divergence and small size source Polarisation: both linear and circular (with IDs) Pulsed Time Structure: pulsed length down to High Stability: submicron source stability in SR Flux = Photons / ( s  BW) Partial coherence in SRs Full T coherence in FELs Brilliance = Photons / ( s  mm2  mrad2  BW ) 10s ps in SRs 10s fs in FELs IoP NPPD Glasgow, 06 April 2011

  4. ESRF SSRF 3rd generation storage ring light sources 1992ESRF, France (EU) 6 GeV ALS, US 1.5-1.9 GeV 1993 TLS, Taiwan 1.5 GeV 1994ELETTRA, Italy 2.4 GeV PLS, Korea 2 GeV MAX II, Sweden 1.5 GeV 1996APS, US 7 GeV LNLS, Brazil 1.35 GeV 1997 Spring-8, Japan 8 GeV 1998BESSY II, Germany 1.9 GeV 2000ANKA, Germany 2.5 GeV SLS, Switzerland 2.4 GeV 2004SPEAR3, US 3 GeV CLS, Canada 2.9 GeV 2006: SOLEIL, France 2.8 GeV DIAMOND, UK 3 GeV ASP, Australia 3 GeV MAX III, Sweden 700 MeV Indus-II, India 2.5 GeV 2008SSRF, China3.4 GeV 2009PETRA-III, D 6 GeV 2011ALBA, E 3 GeV

  5. 3rd generation storage ring light sources under construction or planned NLSL-II > 2011NSLS-II, US 3 GeV SESAME, Jordan 2.5 GeV MAX-IV, Sweden 1.5-3 GeV TPS, Taiwan3 GeV CANDLE, Armenia 3 GeV Max-IV IoP NPPD Glasgow, 06 April 2011

  6. Accelerator physics and technology challenges Photon energy Brilliance Flux Stability Polarisation Time structure Ring energy Small Emittance Insertion Devices High Current; Feedbacks Vibrations; Orbit Feedbacks; Top-Up Short bunches; Short pulses IoP NPPD Glasgow, 06 April 2011

  7. Brilliance and low emittance The brilliance of the photon beam is determined (mostly) by the electron beam emittance that defines the source size and divergence

  8. Brilliance with IDs Thanks to the progress with IDs technology storage ring light sources can cover a photon range from few tens of eV to tens 10 keV or more with high brilliance Medium energy storage rings with In-vacuum undulators operated at low gaps (e.g. 5-7 mm) can reach 10 keV with a brilliance of 1020 ph/s/0.1%BW/mm2/mrad2 IoP NPPD Glasgow, 06 April 2011

  9. Diamond aerial view with the new I13 beamline Diamond is a third generation light source open for users since January 2007 100 MeV LINAC; 3 GeV Booster; 3 GeV storage ring 2.7 nm emittance – 300 mA – 18 beamlines in operation (12 in-vacuum small gap IDs)

  10. Energy 3 GeV Circumference 561.6 m No. cells 24 Symmetry 6 Straight sections 6 x 8m, 18 x 5m Insertion devices 4 x 8m, 18 x 5m Beam current 300 mA (500 mA) Emittance (h, v) 2.7, 0.03 nm rad Lifetime > 10 h Min. ID gap7 mm (5 mm) Beam size (h, v)123, 6.4 mm Beam divergence (h, v)24, 4.2 mrad (at centre of 5 m ID) Diamond storage ring main parametersnon-zero dispersion lattice 48 Dipoles; 240 Quadrupoles; 168 Sextupoles (+ H and V orbit correctors + Skew Quadrupoles ); 3 SC RF cavities; 168 BPMs Quads + Sexts have independent power supplies All BPMS have t-b-t- capabilities IoP NPPD Glasgow, 06 April 2011

  11. Hor.  - beating < 1% ptp Ver.  - beating < 1 % ptp Linear optics modelling and correction Emittance [2.78 - 2.74] (2.75) nm Energy spread [1.1e-3 - 1.0-e3] (1.0e-3) Coupling correction to below 0.1% V beam size at source point 6 μm V emittance 2.2 pm Very good control of the linear optics with LOCO

  12. Top-Up mode • 17th-19th September 2009: 112 h of uninterrupted beam: • 25th January 2011 first full operating week (144 hours ) 0.64% t= 26 h IoP NPPD Glasgow, 06 April 2011

  13. Short bunches at Diamond The equilibrium bunch length at low current is We can modify the electron optics to reduce  z(low alpha optics)  z(nominal)/10  (low_alpha_optics)   (nominal) /100 Comparison of measured pulse length for normal and low momentum compaction 2.5 ps is the resolution of the streak camera Shorter bunch length confirmed by synchrotron tune measurements fs = 340Hz => α1 = 3.4×10-6, σL = 1.5ps fs = 260Hz => α1 = 1.7×10-6, σL = 0.98ps

  14. I09 and I13: “Double mini-beta” and Horizontally Focusing Optics in-vacuum undulators 4 new quadrupoles existing girders modified I13 October 2010 I09 April 2011 new mid-straight girder

  15. Trends in 3rd generation light sources Striving to meet advanced user’s requirements more beamlines (canted undulator from single straight sections) customised optics higher brightness (low emittance – low coupling) higher flux (higher current) short pulses New machine designs or upgrades are targeting 100 pm or less in the horizontal plane … but peak brightness and pulses length cannot compete with FELs IoP NPPD Glasgow, 06 April 2011

  16. Users’ requirements - 4th generation light sources Higher peak brightness Transverse coherence SASE Tunability Ultra short pulses (<100 fs down to sub-fs) Temporal coherence direct seeding - seeding + HG High repetition rates / Time structure SC/NC RF IDs technology or novel schemes Polarisation control Synchronisation to external lasers VUV and THz

  17. FEL radiation properties FELs provide peak brilliance 8 order of magnitudes larger than storage ring light sources Average brilliance is 2-4 order of magnitude larger and radiation pulse lengths are of the order of 100s fs or less Slicing or low charge Many projects target Soft X-rays (here 40 – 1 nm) . Soft X-rays FELs require 1-3 GeV Linacs. Hard X-rays project will also provide Soft X-rays beamlines (Swiss FEL – LCLS)

  18. X-rays FELs

  19. LCLS lasing at 1.5 Å (April 2009)

  20. High brightness beam at LCLS Managing collective effects with high brightness beams is a non trivial AP task MEASURED SLICE EMITTANCE at 20 pC CSR effects at BC2

  21. NLS Conceptual Design Report (May 2010) • The science case requires a light source with • photon energies from THz to X-rays • high brightness • high repetition rate (1 kHz to 100 kHz or more) • short pulses: 1011ppp - 20 fs upgrade to sub-fs pulses • full coherence • The technical solution proposed is based on a combination of advanced conventional lasers and FELs • 2.25 GeV SC linac • seeded harmonic cascaded FEL (50 eV to 1 keV) IoP NPPD Glasgow, 06 April 2011

  22. experimental stations gas filters IR/THzundulators photoinjector diagnostics 3rd harmonic cavity accelerating modules spreader laser heater collimation BC1 BC2 BC3 FELs UK New Light Source (NLS) High brightness electron gun operating (initially) at 1 kHz 2.25 GeV SC CW linac L- band 50-200 pC • 3 FELS covering the photon energy range 50 eV – 1 keV (50-300; 250-800; 430-1000) • GW power level in 20 fs pulses • laser HHG seeded for temporal coherence • cascade harmonic FEL • synchronised to conventional lasers (60 meV – 50 eV) and IR/THz sources for pump probe experiments

  23. A01 BC3 Gun BC2 SPDR FELs LH A04 A02 A09 A05 A39 A10 A06 A03 A11 A07 A12 A08 A13 BC1 A14 Accelerator Physics challenges Soft X-ray are driven by high brightness electron beam 1 – 3 GeV n  1 m ~ 1 kA  /   10–4 This requires: a low emittance gun (norm. emittance cannot be improved in the linac) acceleration and compression through the linac keeping the low emittance The operation of seeded FELs requires in addition e- pulse shape control (flat slice parameters  flat gain length over ~100s fs) careful reduction of jitter of e- beam properties Optimisation validated by start-to-end simulation Gun to FEL Astra/PARMELA Impact-T GENESIS/GINGER Elegant/IMPACT/CSRTrack

  24. FEL physics challenges: need for seeding Advantage of seeded operation vs SASE SASE  >> 1 Seeded  ~ few TFL SASE has a very spiky output: each cooperation length behaves independently: no phase relation among spikes Seedingimproves longitudinalcoherenceshortersaturationlength stability (shottoshotpower, spectrum, ...) controlofpulselength allowssynchronisationtoexternallasers Seed source are not available down to 1 keV. Frequency up-conversion done with FEL itself (HGHG, HGHG cascade, EEHG most unproven yet)

  25. FEL physics challenges: harmonic cascade Optimisation of cascaded harmonic FEL for highest power and highest contrast ratio Conflicting requirements: generate bunching at higher harmonics of interest keep the induced energy spread low but Courtesy N. Thompson

  26. Sub-fs radiation pulses Generation of sub-fs radiation pulses has been proposed with a variety of mechanisms • laser slicing (Zholents, Saldin, Fawley) • mode locking (Thompson, McNeil) • single spike (Bonifacio, Pellegrini) • echo – based (Xiang –Huang-Stupakov) e-beam ~ 100 fs

  27. NLS – recirculatinglinac option High brightness electron gun operating (initially) at 1 kHz 2.25 GeV SC CW linac L- band 50-200 pC Option with recirculating linac (10 modules instead of 18 modules) Linac 8 modules

  28. The ALICE layout and main parameters Accelerator and Laser In Combined Experiments Parameter Value Gun Energy 350 keV Injector Energy 8.35 MeV Max. Energy 35 MeV Linac RF Frequency 1.3 GHz Max Bunch Charge 80 pC Courtesy J. Clarke

  29. The ALICE electron test accelerators • An R&D facility dedicated to accelerator science and technology • Offers a unique combination of accelerator, laser and free-electron laser sources • Enabling studies of electron and photon beam combination techniques • Provides a range of photon sources for development of scientific programmes and techniques • Highlights of the scientific programme include • R&D on SC DC photoinjectors and on SC RF for CW L-band Linacs • Diagnostics (e.g. ultrashort pulses) timing and synchronisation • Energy recovery - Emma injector • Compton backscattering - THz radiation • and IR-FEL IoP NPPD Glasgow, 06 April 2011

  30. FIR wavelength FEL (8  6 m) First Lasing Data: 23/10/10 Simulation (FELO code)

  31. Possible future directions for 4th generation light sources • Ultracold injectors: low emittance, low charge, to shorten the saturation length • Insertion Devices: development of new undulators beyond Apple-II, compact, shorter periods, higher fields, wakefield control, compact (e.g. Superconducting U) • RF: Optimise performance and reduce cost of SC RF (gradient choices 13-15 MV/m for LBNL, NLS, BESSY) or use simple low risk design with high gradient (possibly high repetition rate based on C-band X-band) • FEL physics: Critical assessment of various seeding schemes, non-seeding and slicing options, HHG, HGHG cascade and sub fs pulses • AP Physics: alternative compression schemes to avoid the limits posed by microbunching (velocity bunching) • Diagnostics: New diagnostics for ultra short bunches, arrival time, low charge but also dealing with COTR • Timing and synhcronisation: sub 10-fs resolution over 100s m; long term stability • Stability and feedbacks: positions (sub m over large frequency range), energy, charge, …

  32. Beyond fourth generation light sources The progress with laser plasma accelerators in the last years have open the possibility if using them for the generation for synchrotron radiation and even to drive a FELs First observation of undulator radiation achieved in Soft X-ray FEL type beam can be achieved with relatively modest improvements on what presently achieved and significant improvement on the stability of these beams Layout of a compact light source driven by a LPWA

  33. LBNL-Oxford experiment (2006) Laser plasma wakefield accelerators demonstrated the possibility of generating GeV beam with promising electron beam qualities W. P. Leemans et al. Nature Physics2 696 (2006) E = 1.0 +/-0.06 GeV ΔE = 2.5% r.m.s Δθ = 1.6mradr.m.s. Q = 30 pC charge Capillary: 310 μm Laser: 40 TW Density: 4.3 ×1018 cm-3 Density 4.3 1018 cm–3 Laser Power > 38 TW (73 fs) to 18 TW (40 fs) IoP NPPD Glasgow, 06 April 2011

  34. Undulator radiationfrom LPWA First combination of a laser-plasma wakefield accelerator, producing 55–75MeV electron bunches, with an undulator to generate visible synchrotron radiation

  35. Undulator radiation Soft Xrays MPQ experiment radiation spectrum Electron spectrum Spontaneous undulator radiation and off-axis dependence M. Fuchs et al, Nature Physics (2009)

  36. Undualtor radiation Soft Xrays – MPQ experiment Stability of the electron beam quality is crucial for a successful FEL operation IoP NPPD Glasgow, 06 April 2011

  37. Alpha - X Project Courtesy M. Wiggins IoP NPPD Glasgow, 06 April 2011

  38. Diagnosticsdevelopment Can LPWA beam drive a Free Electron Laser (e.g. in the Soft X-rays) ? Activity on diagnostics to characterise such electron pulses Energy - Energy spread – Emittance - Pointing stability 125 MeV divergence 2-4 mrad Average emittance 2 um – best emtittance 1 um Resolution limted Courtesy M. Wiggins IoP NPPD Glasgow, 06 April 2011

  39. Alpha X - Summary Beam quality appear to be close to the one required for driving FEL in the UV - XUV: 170 MeV beam Measured emittance below 1 m Charge 1 – 5 pC in 2 fs corresponding to 1-2 kA Measured energy spread better 1% should be sufficient at least to measure FEL gain in the XUV range Progress is advancing nicely towards a working compact soft X-ray driven by a LPWA electron beam based on gas jet or capillary accelerator talk by D: Jarosinsky tomorrow IoP NPPD Glasgow, 06 April 2011

  40. Conclusions Users’ requirements pose difficult challenges for storage ring and FEL design and operation The methods and solutions developed show that these challenges can be met. Experimental tests of seeding in the coming future will confirm the extent of seeding capabilities to cover the whole Soft X-ray spectrum down to 1 nm However, more compact and economic solutions to meet the present challenges are needed: Injectors – IDs – LINACs RF technology …. LPWA Thank you for your attention. IoP NPPD Glasgow, 06 April 2011

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