Diamond Light Source Status and Future Challanges R

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 Ge. V 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

Diamond Layout 100 Me. V Linac 3 Ge. V Booster C = 158. 4 m 3 Ge. V Storage Ring technical plant C = 561. 6 m Experimental Hall and Beamlines peripheral labs. and offices office building 235 m future long beamlines 235 m

Milestones and key facts 31 st August 2005 First LINAC beam (100 Me. V) 21 st December 2005 First turn in booster 3 rd May 2006 First turn in Storage ring Beamline commissioning start 23 rd October 2006 First users 29 th January 2007 15 th September 2007 300 m. A 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 DL-RAL Joint Accelerator Workshop 20 January 2009

Diamond storage ring main parameters non-zero dispersion lattice Energy Circumference 3 Ge. V 561. 6 m No. cells 24 Symmetry 6 Straight sections 6 x 8 m, 18 x 5 m Insertion devices 4 x 8 m, 18 x 5 m Beam current 300 m. A (500 m. A) Emittance (h, v) 2. 7, 0. 03 nm rad Lifetime Min. ID gap Beam size (h, v) 48 Dipoles; 240 Quadrupoles; 168 Sextupoles (+ H / V orbit correctors + Skew Quadrupoles ); 3 SC RF cavities; 168 BPMs > 10 h 7 mm (5 mm) 123, 6. 4 m Beam divergence (h, v) 24, 4. 2 rad (at centre of 5 m ID)

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

Storage Ring Closed Orbit < 1 m (first achieved 22 th October 2006) 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:

Correction of linear optics with LOCO (Linear Optics from Closed Orbit) LOCO: fits quadrupoles to reproduce 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.

Emittance and energy spread measured using two X-ray pinholes cameras Measured emittance very close to theoretical values confirms the optics Emittance 2. 78 (2. 75) nm Energy spread 1. 1 e-3 (1. 0 e-3) Emittance coupling 0. 5% Emittance coupling is now routinely corrected to 0. 1% with LOCO Closest tune approach 0, rms Dy 1 mm

13 Insertion Devices operational Beamline ID Type I 02 U 23 In-vacuum I 03 U 21 In-vacuum I 04 U 23 In-vacuum and I 06 HU 64 APPLE-II first ID of Phase II I 15 SCW 3. 5 T Superconducting Multipole Wiggler I 16 U 27 In-vacuum I 18 U 27 In-vacuum I 22 U 25 In-vacuum I 07 U 23 In-vacuum I 11 U 22 In-vacuum I 19 U 22 In-vacuum I 24 U 21 In-vacuum I 04. 1 30. 8 mm Short ex-vacuum • • 10 in-vacuum undulators 1 variable polarization APPLE-II device 1 3. 5 T superconducting wiggler 1 short ex-vacuum 7 IDS in Phase I were installed and commissioned in early 2007

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 3 rd 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

Ground vibrations to beam vibrations Amplification factor girders to beam: H 31 (theory 35); V 12 (theory 8); 1 -100 Hz Position (μm) Angle (μrad) Horizontal Vertical Long Straight Standard Straight Target 17. 8 12. 3 1. 26 0. 64 Measured 3. 95 (2. 2%) 2. 53 (2. 1%) 0. 70 (5. 5%) 0. 37 (5. 8%) Target 1. 65 2. 42 0. 22 0. 42 measured 0. 38 (2. 3%) 0. 53 (2. 2%) 0. 14 (6. 3%) 0. 26 (6. 2%)

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 Standard Straight H Standard Straight V Target 12. 3 0. 64 No FOFB 2. 53 (2. 1%) 0. 37 (5. 8%) FOFB On 0. 86 (0. 7%) 0. 15 (2. 3%) Target 2. 42 0. 42 No FOFB 0. 53 (2. 2%) 0. 26 (6. 2%) FOFB On 0. 16 (0. 7%) 0. 09 (2. 1%) 1 -100 Hz Position (μm) Angle (μrad)

Summary of Current Machine Status Target Achieved Energy 3 Ge. V Beam current 300 m. A Machine Development 250 m. A User Mode Emittance - horizontal - vertical 2. 7 nm rad 27 pm rad 2. 7 nm rad 4 -50 pm rad ~ 27 pm in User Mode Lifetime at 300 m. A > 10 h Min. ID gap 5 -7 mm User Mode, dep. on ID 7 mm ~ 18 h 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

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 BPMs block stability Improved stability • Constant heat load • Beam current dependence of BPMs Crucial for long term sub- m stability Flexible operation • Lifetime less important • Smaller ID gaps • Lower coupling • without Top-Up 10 m • with Top-Up < 1 m

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

Top-Up operation • First operation with external users, 3 days, Oct. 28 -30 th • 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

Future Insertion Devices Beamline date Type I 12 Mar 09 4. 2 T Superconducting Multipole Wiggler; contract with BINP; Beamline extending outside diamond buliding I 20 Jun 09 I 07 I 10 I 13 I 09 2 x hybrid wigglers 2 T, W 83, construction in-house; End 09 Cryogenic Permanent Magnet Undulator (U 17. 7) contract with Danfysik. Will substitute the in-vacuum U 23 device installed as a temporary measure. 2010 Two APPLE II devices with 10 Hz polarization switching using 5 kicker scheme; engineering implications under study 2 girder changes 2010 Two In-vacuum undulators with “double mini-beta” optics proposed; beam dynamics and engineering implications under study. 1 or 2 girder changes Beamline extending outside diamond buliding 2011 Helical undulator + in-vac. CPMU, with “double mini-beta” optics proposed; beam dynamics implications under study. 1 or 2 girder changes

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’

I 13 beamline DL-RAL Joint Accelerator Workshop 20 January 2009

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 Low – alpha optics Crab Cavities Higher Harmonic Cavities Synchro-betatron kicks RF voltage modulation 3) Laser induced local energy-density modulation Femto–slicing

Low alpha optics If high current effects are negligible the bunch length is = 1. 7 10– 4; V = 3. 3 MV; = 9. 6 10– 4 z = 2. 8 mm (9. 4 ps) 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)

Machine tests with 1 ps lattice fs = 340 Hz => α 1 = 3. 4× 10 -6, σL = 1. 5 ps fs = 260 Hz => α 1 = 1. 7× 10 -6, σL = 0. 98 ps fs=340 Hz fs=260 Hz ε = 34 nm. rad; κ = 0. 03% Qx = 21. 137; Qy = 12. 397

Future Work • 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 m. A) and TMBF impedance database; characterization of the instabilities (multi-bunch, single bunch) • Maintain/Improve Top-up, FOFB performance • Low alpha optics for users Thanks to R. Fielder, E. Longhi, I. Martin, B. Singh, J. Rowland staff from Diagnostics, Controls, Operations, IDs, RF, … DL-RAL Joint Accelerator Workshop 20 January 2009