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Diamond Light Source Status and Future Challanges

Diamond Light Source Status and Future Challanges. R. Bartolini Diamond Light Source Ltd and John Adams Institute University of Oxford. DL-RAL Joint Accelerator Workshop 20 January 2009. Summary. 1) Introduction to Diamond 2) Status of the 3 GeV Storage Ring

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Diamond Light Source Status and Future Challanges

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  1. Diamond Light Source Status and Future Challanges R. Bartolini Diamond Light Source Ltd and John Adams Institute University of Oxford DL-RAL Joint Accelerator Workshop 20 January 2009

  2. Summary 1) Introduction to Diamond 2) Status of the 3 GeV Storage Ring Orbit correction;Optics control; IDs; Orbit stability; 3) Latest developments and future challenges Top-Up operation; Further ID installation;Customised optics; Ultra short radiation pulse generation; DL-RAL Joint Accelerator Workshop 20 January 2009

  3. Diamond Layout 100 MeV Linac 3 GeV Booster C = 158.4 m 3 GeV Storage Ring C = 561.6 m Experimental Hall and Beamlines technical plant peripheral labs. and offices office building 235 m future long beamlines 235 m

  4. First LINAC beam (100 MeV) First turn in booster First turn in Storage ring Beamline commissioning start First users 300 mA January 2009: 13 IDs operational 2007: 3120 h operation (uptime for users 92.4%) 2008: 4080 h operation (uptime for users 94.9%) 2009: 4656 h operation 31st August 2005 21st December 2005 3rd May 2006 23rd October 2006 29th January 2007 15th September 2007 Milestones and key facts DL-RAL Joint Accelerator Workshop 20 January 2009

  5. Diamond storage ring main parametersnon-zero dispersion lattice 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) 48 Dipoles; 240 Quadrupoles; 168 Sextupoles (+ H / V orbit correctors + Skew Quadrupoles ); 3 SC RF cavities; 168 BPMs

  6. Diamond Storage Ring DL-RAL Joint Accelerator Workshop 20 January 2009

  7. The beam orbit is corrected to the BPMs zeros by means of a set of 168 dipole corrector magnets: the BPMs can achieve sub-m precision; the orbit rms is corrected to below 1 m rms: Storage Ring Closed Orbit < 1m(first achieved 22th October 2006)

  8. Correction of linear optics with LOCO(Linear Optics from Closed Orbit) LOCO: fits quadrupoles to reproduce the theoretical closed orbit response matrix circles = model crosses = measured Modified version of LOCO with constraints on gradient variations (see ICFA newsletter, Dec’07)  - beating reduced to 0.4% rms Quadrupole variation reduced to 2% Results compatible with mag. meas.

  9. Emittance and energy spreadmeasured using two X-ray pinholes cameras Measured emittance very close to the theoretical values confirms the optics Emittance 2.78 (2.75) nm Energy spread 1.1e-3 (1.0e-3) Emittance coupling 0.5% Emittance coupling is now routinely corrected to 0.1% with LOCO Closest tune approach 0, rms Dy 1 mm

  10. 13 Insertion Devices operational 7 IDS in Phase I and first ID of Phase II were installed and commissioned in early 2007 • 10 in-vacuum undulators • 1 variable polarization APPLE-II device • 1 3.5T superconducting wiggler • 1 short ex-vacuum

  11. Orbit stability requirements at Diamond Beam stability should be better than 10% of the beam size and divergence but IR beamlines will have tighter requirements for 3rd generation light sources this implies sub-m stability For Diamond nominal optics (at the centre of the short straight sections) • Strategies and studies to achieve sub-m stability • identification of sources of orbit movement • passive damping measures • orbit feedback systems

  12. Ground vibrations to beam vibrations Amplification factor girders to beam: H 31 (theory 35); V 12 (theory 8);

  13. Global fast orbit feedback at Diamond Significant reduction of the rms beam motion up to 100 Hz; Higher frequencies performance limited mainly by the correctors power supply bandwidth

  14. Summary of Current Machine Status Target Achieved Energy 3 GeV 3 GeV Beam current 300 mA 300 mA Machine Development 250 mA User Mode Emittance - horizontal 2.7 nm rad 2.7 nm rad - vertical 27 pm rad 4-50 pm rad ~ 27 pm in User Mode Lifetime at 300 mA > 10 h ~ 18 h Min. ID gap7 mm 5-7 mm User Mode, dep. on ID Stability< 10% 2.3% (H), 6.3% (V) No feedback of beam size 0.7% (H), 2.3% (V) Feedback, 1-100 Hz & divergence DL-RAL Joint Accelerator Workshop 20 January 2009

  15. Top-Up motivation Top-Up operation consists in the continuous (very frequent) injection to keep the stored current constant to prevent the natural beam current decay • Higher average brightness • Higher average current • Constant flux on sample • Improved stability • Constant heat load • Beam current dependence of BPMs • Flexible operation • Lifetime less important • Smaller ID gaps • Lower coupling • BPMs block stability • without Top-Up  10 m • with Top-Up < 1 m • Crucial for long term sub- m stability

  16. User-Mode Operations “Standard” operation: 250 mA maximum, 2 injections/day DL-RAL Joint Accelerator Workshop 20 January 2009

  17. Top-Up operation • First operation with external users, 3 days, Oct. 28-30th • No top-up failures, no beam trips due specifically to top-up • Now Top-Up is the regular user operation mode DL-RAL Joint Accelerator Workshop 20 January 2009

  18. Future Insertion Devices

  19. Customised optics in long straight sections A long straight sections is divided into two by a triplet of quadrupoles to achieve double mini beta in V and a virtual focus in H for coherence applications Pos. ‘A’

  20. I13 beamline DL-RAL Joint Accelerator Workshop 20 January 2009

  21. Ultra-short radiation pulses in a storage ring There are three main approaches to generate short radiation pulses in storage rings e– bunch 1) shorten the e- bunch 2) chirp the e-bunch + slit or optical compression 3) Laser induced local energy-density modulation Low – alpha optics Higher Harmonic Cavities RF voltage modulation Femto–slicing Crab Cavities Synchro-betatron kicks

  22. If high current effects are negligible the bunch length is Low alpha optics z = 2.8 mm (9.4 ps)  = 1.710–4; V = 3.3 MV;  = 9.6 10–4 z depends on the magnetic lattice (quadrupole magnets) via  We can modify the electron optics to reduce   (low_alpha_optics)  10–6 z 0.3 mm (1 ps)

  23. fs=260Hz Machine tests with 1 ps lattice fs = 340Hz => α1 = 3.4×10-6, σL = 1.5ps fs = 260Hz => α1 = 1.7×10-6, σL = 0.98ps fs=340Hz ε = 34 nm.rad; κ = 0.03% Qx = 21.137; Qy = 12.397

  24. Continue optics optimisation • maintain nominal optics, lifetime characterisation, injection efficiency; • characterisation of the non-linear optics (pinger magnet installed by end of 2007) • Continue ID commissioning (Phase II and Phase III ID installation till 2014) • optics compensation vs gap, DA effect, lifetime vs gap, frequency map vs gap • ID request operation at 5 mm gap • High current operation (300 mA) and TMBF • impedance database; characterization of the instabilities (multi-bunch, single bunch) • Maintain/Improve Top-up, FOFB performance • Low alpha optics for users Future Work Thanks to R. Fielder, E. Longhi, I. Martin, B. Singh, J. Rowland and staff from Diagnostics, Controls, Operations, IDs, RF, … DL-RAL Joint Accelerator Workshop 20 January 2009

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