1. Options for SuperB as a light source R. Bartolini Diamond Light Source Ltd and John Adams Institute, Dept. of Physics, University of Oxford 2 nd superB meeting, Frascati 13 th December 2011

2. Motivations Luminosity and brilliance scale together both increase with the stored beam current both increase with smaller emittances (…within limits beam beam, collective effects, diffraction, etc) to get to 10 36 cm –2 s –1 the superB lattice has excellent properties which make it a competitive 3 rd generation light source 2 nd superB meeting, Frascati 13 th December 2011

3. 1992ESRF, France (EU) 6 GeV ALS, US 1.5-1.9 GeV 1993TLS, Taiwan1.5 GeV 1994ELETTRA, Italy2.4 GeV PLS, Korea 2 GeV MAX II, Sweden1.5 GeV 1996APS, US7 GeV LNLS, Brazil1.35 GeV 1997Spring-8, Japan8 GeV 1998BESSY II, Germany1.9 GeV 2000ANKA, Germany2.5 GeV SLS, Switzerland2.4 GeV 2004SPEAR3, US 3 GeV CLS, Canada2.9 GeV 2006:SOLEIL, France2.8 GeV DIAMOND, UK 3 GeV ASP, Australia3 GeV MAX III, Sweden700 MeV Indus-II, India2.5 GeV 2008SSRF, China 3.4 GeV 2009PETRA-III, Germany6 GeV 2011ALBA, Spain3 GeV 3 rd generation storage ring light sources ESRF Diamond

4. > 2011NSLS-II, US 3 GeV MAX-IV, Sweden1.5-3 GeV SOLARIS, Poland1.5 GeV SESAME, Jordan 2.5 GeV TPS, Taiwan 3 GeV CANDLE, Armenia3 GeV PEP-X, USA4.5 GeV 3 rd generation storage ring light sources under construction or planned NLSL-II Max-IV SuperB, Italy6.7 GeV 4.2 GeV 2 nd superB meeting, Frascati 13 th December 2011

5. Motivations: comparison with other light sources SuperB HER – 6.7 GeV 2 nm emittance 2 A average current ESRF upgrade (6 GeV) 4 nm emittance 300 mA (200 mA present) Pep-X 4.5 GeV 140 pm emittance and 1.5 A 10 pm with DW – 200 mA 2 nd superB meeting, Frascati 13 th December 2011 SuperB can do better Very tough competitor for SuperB …when operating

6. Emittance in 3 rd GLS, DR and colliders 2 nd superB meeting, Frascati 13 th December 2011

7. Brilliance with IDs (medium energy light sources) 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 10 20 ph/s/0.1%BW/mm 2 /mrad 2 2 nd superB meeting, Frascati 13 th December 2011

8. Brilliance with IDs (ESRF upgrade) Brilliance gain on the ESRF upgrade driven by higher stored current smaller vertical emittance and longer straight sections Low Emittance Rings Workshop, Crete 3 rd October 2011

9. Insertions for SuperB – option 1 Courtesy M. Biagini 2 sections with 5 insertions in a row in the middle of the arcs. 10 beamlines in total Available straight length 3.2 m Adequate for one Insertion Device 2 nd superB meeting, Frascati 13 th December 2011

10. Insertions for SuperB – option 2 Courtesy M. Biagini 6 distributed straight sections using the existing alternating cell structure 3  - 3  /2 12 beamlines in total Available straight length 3.2 m Adequate for one Insertion Device This option requires minimal changes to the baseline design 2 nd superB meeting, Frascati 13 th December 2011

11. option 2 – modification of 3/2 pi cell (April 2011) 2 nd superB meeting, Frascati 13 th December 2011

12. option 2 – modification of 3/2 pi cell (May 2011) 2 nd superB meeting, Frascati 13 th December 2011

13. option 2 – modification of 3/2 pi cell (Nov 2011) 2 nd superB meeting, Frascati 13 th December 2011

14. option 2 – modification of 3/2 pi cell (Dec 2011 WIP) 2 nd superB meeting, Frascati 13 th December 2011 Triplet moved upstream: length of straight section 3.5 m  5.1 m beta_y smaller  helps with Beam Stay Clear with small gap undulators contribution of cell to emittance unchanged small changes in optics function at the cell beginning/end phase advance closer to 3  /2 (H) and  /2 (V) WIP but no showstopper

15. Brilliance SuperB vs ESRF (and ESRF upgrade) Used U23 of ESRF ID27 ESRF parameters (4nm) 200 mA 0.7% coupling 2 m undulator ESRF upgrade (4nm) 300 mA 0.3% coupling 4 m undulator SuperB (2nm) 500 mA 0.7% coupling 2m undulator 2 nd superB meeting, Frascati 13 th December 2011 superB ESRF upgrade ESRF

16. Brilliance SuperB vs ESRF (and ESRF upgrade) Used U23 of ESRF ID27 ESRF parameters (4nm) 200 mA 0.7% coupling 2 m undulator ESRF upgrade (4nm) 300 mA 0.3% coupling 4 m undulator SuperB (2nm) 500 mA 0.3% coupling 4m undulator 2 nd superB meeting, Frascati 13 th December 2011

17. Brilliance SuperB vs ESRF (and ESRF upgrade) Used U23 of ESRF ID27 ESRF parameters (4nm) 200 mA 0.7% coupling 2 m undulator ESRF upgrade (4nm) 300 mA 0.3% coupling 4 m undulator SuperB (2nm) 2 A 0.3% coupling 4m undulator 2 nd superB meeting, Frascati 13 th December 2011

18. Bending magnet radiation ESRF  = 23.2 m  critical energy  c = 20.7 keV SuperB (HER)  = 85.2 m  critical energy  c = 7.5 keV SuperB (LER)  = 28.4 m  critical energy  c = 5.8 keV Bending magnet in HER SL CELL can be made shorter and stronger to increase the critical energy 2 nd superB meeting, Frascati 13 th December 2011 Integrated flux SuperB HER2A SuperB HER 500 mA ESRF 300 mA

19. Hybrid or camshaft mode: combination of multibunch and single bunch e.g. 500 mA in consecutive bunches in 3/4 of the ring + e.g. 10 mA single bunch in the centre of the "dark" portion 500 ns Time resolved pump-(Xray)probe experiment 2 nd superB meeting, Frascati 13 th December 2011 CDR bunch length at full current is 5 mm – 17 ps

20. Low – alpha optics Higher Harmonic Cavities RF voltage modulation Femto–slicing 1) shorten the e- bunch2) chirp the e-bunch + slit or optical compression 3) Laser induced local energy-density modulation e – bunch Crab Cavities Synchro-betatron kicks There are three main approaches to generate short radiation pulses in storage rings Ultra-short radiation pulses in a storage ring These approaches will require careful studies and will required significnaln modification to the storage ring. Can the Linac be used a la SPPS – MaX-IV?

21. Preliminary requirements from IIT’s users Beamlines of interest for IIT are X-ray diffraction SAXS imaging with phase contrast plus possibly IR high photon energy beamline100 keV for industrial applications ESRF upgrade used as paradigm e.g. ID21 ESRF 2–9 keV 3 IDs in one section one out of vacuum (41 mm undulator), one wiggler, one APPLE device Courtesy E. Di Fabrizio (IIT) 2 nd superB meeting, Frascati 13 th December 2011

22. Preliminary requirements from IIT’s users Photon Energy 4-15 keV one beamline possibly 100 keV or higher Spot size – spot divergence low divergence (1 mrad down to 1 urad) small spot size (below 1 um) possibly symmetric, i.e. round photon beam Photon Flux better than ESRF upgrade  E/E 10 –4 (with monochromators) Polarisation Linear might consider circular or elliptic in a second phase Pulse length 20 ps are adequate, longer is also fine, not an issue; THz beamline might requires shorter pulses in a second phase Courtesy E. Di Fabrizio (IIT) 2 nd superB meeting, Frascati 13 th December 2011

23. Undulators for e.g. 4-15 keV (IIT domain) Cover continuously the range 4-15 keV e.g. used U29 with SuperB (2nm) K = 2.3 and 7 mm gap 500 mA 0.7% coupling 2m undulator 500 mA 0.3% coupling 4m undulator 2 A 0.3% coupling 4m undulator 2 nd superB meeting, Frascati 13 th December 2011 Can also use a revolver undulator and work in first harmonics at lower K for better heat load management

24. Preliminary requirements from IIT’s users QMUL, London 12 th September 2011 Improvement expected also from the construction of state-of-the-art beamlines e.g. long beamlines (  100 m) for small focus or coherence e.g. Diamond I13 250 m from ID to sample

25. Provisional beamlines layout Tor Vergata Campus

26. optics controls and operational challenges State of the art light sources proved emittance and stability of the type required for Emittance tuning and coupling correction Dynamics aperture Momentum aperture and Touschek lifetime Stability (Top-Up and feedback systems) OK ….BUT @ 300-500 mA (for medium energy rings) The main issues are related to the operation with high current which is a new territory for light sources Collective effects heat load on beamlines FE and components

27. Linear optics modelling with LOCO Linear Optics from Closed Orbit response matrix – J. Safranek et al. Modified version of LOCO with constraints on gradient variations (see ICFA Newsl, Dec’07)  - beating reduced to 0.4% rms Quadrupole variation reduced to 2% Results compatible with mag. meas. and calibrations Hor.  - beating Ver.  - beating LOCO allowed remarkable progress with the correct implementation of the linear optics Quadrupole gradient variation

28. Measured emittances Coupling without skew quadrupoles off K = 0.9% (at the pinhole location; numerical simulation gave an average emittance coupling 1.5% ± 1.0 %) Emittance [2.78 - 2.74] (2.75) nm Energy spread [1.1e-3 - 1.0-e3] (1.0e-3) After coupling correction with LOCO (2*3 iterations) 1 st correction K = 0.15% 2 nd correction K = 0.08% V beam size at source point 6 μm Emittance coupling 0.08% → V emittance 2.2 pm Variation of less than 20% over different measurements

29. Comparison machine/model and Lowest vertical emittance Model emittance Measured emittance  -beating (rms) Coupling* (  y /  x ) Vertical emittance ALS 6.7 nm 0.5 %0.1%4-7 pm APS 2.5 nm 1 %0.8%20 pm ASP 10 nm 1 %0.01%1-2 pm CLS 18 nm17-19 nm4.2%0.2%36 pm Diamond 2.74 nm2.7-2.8 nm0.4 %0.08%2.2 pm ESRF 4 nm 1%0.1%4.7 pm SLS 5.6 nm5.4-7 nm4.5% H; 1.3% V0.05%2.0 pm SOLEIL 3.73 nm3.70-3.75 nm0.3 %0.1%4 pm SPEAR3 9.8 nm < 1%0.05%5 pm SPring8 3.4 nm3.2-3.6 nm1.9% H; 1.5% V0.2%6.4 pm SSRF 3.9 nm3.8-4.0 nm<1%0.13%5 pm * best achieved

30. Top-Up operation consists in the continuous (very frequent) injection to keep the stored current constant – with beamline shutters open. Stability and Top-Up Operation Already in operation at APS, SLS, SPring8, TLS New machines such as Diamond, SOLEIL are also operating Top-Up Retrofitted in ALS, SPEAR3, ELETTRA, BESSY-II, ESRF (few bunches mode) Slow beam drifts due to varying thermal load practally eliminated by Top-Up  I/I  10 –3 Standard decay modeTop-Up mode

31. Significant reduction of the rms beam motion up to 100 Hz; Higher frequencies performance limited mainly by the correctors power supply bandwidth Stability and global fast orbit feedback 1-100 Hz Standard Straight H Standard Straight V Position (μm) Target12.30.64 No FOFB2.53 (2.1%)0.37 (5.8%) FOFB On0.86 (0.7%)0.15 (2.3%) Angle (μrad) Target2.420.42 No FOFB0.53 (2.2%)0.26 (6.2%) FOFB On0.16 (0.7%)0.09 (2.1%)

32. Comments on the compatibility of light source / collider For light source operation to be parasitic to collider operation and compete with other state of the art light sources it needs: Orbit and optics control: the orbit and optics must be controlled at all the source points not just at the interaction points The beamlines do not want to re-align their optics. The orbit should be back to the beamline within few hundreds of microns after a shut down so that only minor adjustments are made. >10% beat-beating is considered unacceptable There is no freedom to use the orbit to correct the optics at least at the source point. 2 nd superB meeting, Frascati 13 th December 2011 Clear understanding of the heat load management e.g. optics design, distances, material, cooling systems, etc

33. Comments on the compatibility of light source / collider Stability: Orbit variation up to 100 Hz or more must be compensated. This requires a FOFB. Additional variation when moving the IDs gap Thermal load variation generate BPM block movement of the order of 10-15 um in decay mode at 150 mA at Diamond. The variation heat load of a 6 GeV 0.7 A beam will be huge. Top up required for stability Lifetime – Touschek lifetime requires large momentum aperture. (3-4%). True even in Top-Up. Watch alpha_2. However when parasitic to the collider the lifetime is dominated by collisions (beam beam bremsstrahlung). High current operation: Collective effects stronger in B factories, but will be made more acute if in-vacuum ID and narrow gap vessels are to be introduced. IBS does not seem to be a problem for most recent light sources (e.g NLSL-II) 2 nd superB meeting, Frascati 13 th December 2011

34. Acknowledgments M. Biagini, P. Raimondi (INFN) E. Levichev, S.Syniatkin (BINP) E. Di Fabrizio (IIT) and the SILS WG M. Benfatto (INFN) M. Cianci (embl-Hamburg) M. Coreno (ELETTRA) F. D’Acapito (ESRF) L. Giannessi (ENEA) L. Paolasini (ESRF) C. Mariani (Universita Roma and SILS president) 2 nd superB meeting, Frascati 13 th December 2011 Thank you for your attention