Status of the Diamond Light Source Ian Martin On behalf of the Diamond Team ESLS-XXIII Workshop Paul Scherrer Institute, Villigen 24th November 2015

Talk Outline Introduction to Diamond Operations update Statistics RF status New insertion devices Injection studies / SR septum move DDBA upgrade status Conclusions Ian Martin ESLS XXI, PSIII, (Nov 2015)

Diamond Light Source Diamond Light Source Diamond is the UK’s national synchrotron radiation facility Located at Rutherford Appleton Laboratory, Oxfordshire Construction began March 2003 Commissioning 2005 - 2006 Start of user operations Jan 2007 Lattice DBA Structure 24 cell Symmetry 6 (broken by mini-beta cells) Straights 18 × 5m / 6 × 8m Energy 3 GeV Circumference 561.6 m H / V Tunes 27.210 / 13.364 H / V Chromaticity 2.0 / 2.0 H / V Emittance 2.6 nm.rad / 8 pm.rad Energy spread 0.096 % Current 300 mA Lifetime >7h Ian Martin, AS Visit, Jan 2015

Diamond operating modes during 2015 (4344 h out of 5040 h completed): Fill Patterns Diamond operating modes during 2015 (4344 h out of 5040 h completed): 686 bunch mode (192 h) 900 bunch mode (3768 h) Single-bunch hybrid (456 h) Multi-bunch hybrid (168 h) Low-alpha THz (192 h) Low-alpha short-pulse (120 h) 156 bunch mode (144 h) Currently investigating alternative ‘THz’ mode, reducing alpha and bunch current in order to drop below bursting threshold but maintain THz spectrum (>50 cm-1 required). Alpha to remain negative. Ian Martin ESLS XXI, PSIII, (Nov 2015)

Operations Update Courtesy V. Kempson * + Currently above target >72h MTFB for the first time * + *Allocated hours adjusted after cavity swap +Data up to end Run#4 2015 Courtesy V. Kempson Ian Martin ESLS XXI, PSIII, (Nov 2015)

Operations Update Courtesy V. Kempson Ian Martin ESLS XXI, PSIII, (Nov 2015)

RF Cavity 2B Failure Cavity 2B failed during cool-down on 2nd Sept 2014 Removed from ring and sent back to RI for repair; replaced with new Cavity 2D Leak found on indium seal on fluted beam tube (FBT) from helium cryostat into cavity UHV Estimated return December 2015 Lost 2 weeks user time as a result of swap Run 5 start brought forward by 1 week to partially compensate lost user time Temperature Helium O2 Vacuum Courtesy C. Christou Ian Martin ESLS XXI, PSIII, (Nov 2015)

RF Cavity 2D Failure Cavity 2D installed September 2014 (Site Acceptance Tests incomplete) Poor reliability >1 MV, many fast vacuum trips, unable to condition out. Solved by dropping to 0.8MV Window leak occurred 14th July during beam tests after a regular partial warm-up / pulse conditioning session Temporarily repaired using vacuum sealant. Cavity detuned and kept cold for remainder of the run (150 mA, Cavity 3C increased from 1.4 MV to 1.7 MV) Replaced with Cavity 1A in August; subsequent performance has been good RF window will be swapped in RAL Space clean room (winter 2015, date TBC) Courtesy C. Christou Ian Martin ESLS XXI, PSIII, (Nov 2015)

Normal Conducting Cavity Plan In order to mitigate impact of SCF failure, two EU HOM-damped normal conducting cavities have been ordered from RI (cf BESSY, ALBA): Can be run at modest voltages to supplement existing SC cavities, reducing power requirements of present amplifiers (trip without beam loss) Immediate in-house repairs of NC cavities possible Acceptance scheduled for March 2017 Will be installed upstream of IDs in straights adjoining existing RF straight Requires amplifier modification (one ampl. split for 2 cavities). Use third amplifier currently powering RF Test Facility (investigating options for replacement amplifier for RFTF – solid state preferred option) New LLRF required (collaboration with / development of ALBA system) digital LLRF offers greater flexibility To be adapted to existing cavities Courtesy C. Christou Ian Martin ESLS XXI, PSIII, (Nov 2015)

0.25-3 keV (variable polarisation) I21 (RIXS) Undulator Installed in Aug., commissioned Nov. Long straight prev. used for diagnostics (relocation of equipment required) Local reduction in beta functions to allow narrow chamber and improve matching for beamline: βx: 9.8m->6.6m / βy: 6.1m->3.4m Optics in place since June, no issues Photon Energy 0.25-3 keV (variable polarisation) Device Period 56 mm Number of Periods 89 Nominal Length 5.0 m Technology APPLE-II Minimum Gap 20 mm Ian Martin ESLS XXI, PSIII, (Nov 2015)

Cryo-cooled, In-vac Hybrid I24 CPMU Upgrade I24 Upgrade project aims to increase brilliance and flux at ~12.6 keV Super-Conducting and Cryo-Permanent Magnet Undulator designs considered; in-house CPMU selected based on cost, risk reduction, timescales Installation scheduled March 2016 Similar upgrade also underway for I03 (Aug 2016) ×1.85 Photon Energy 7-25 keV Device Period 17.6 mm Number of Periods 117 Nominal Length 2.0 m Technology Cryo-cooled, In-vac Hybrid Minimum Gap 5 mm ×4.5 ×4.5 Ian Martin ESLS XXI, PSIII, (Nov 2015)

Injection Studies Storage ring septum has been moved from -16 mm to -12 mm from stored beam Allows kickers to be run at lower field – (residual kick reduced from ±300 / 150 μm in H / V to ±250 / 40 μm following move) Allows for single-shot, on-axis injection (DDBA upgrade commissioning) Required new upstream and downstream bellows to be manufactured SR septum vacuum leak caused by short-circuit 15/11/2015. Replaced with spare. Kicker vessel swap planned for March 2016 (damaged coating on existing vessels) Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Upgrade Project Idea from Diamond-II storage ring upgrade project: replace existing cell 2 with a modified 4BA (DDBA) cell DDBA cell Introduces an additional straight section (VMX beamline 0.7 m ex-vac -> 2.0 m in-vac) Serves as a prototype for full lattice upgrade Lots of R&D required (magnet design challenging, vacuum with small apertures, engineering integration, etc.) Additional straight Insertion Device existing DBA cell modified DDBA cell BM beamline ID beamline Courtesy R. Bartolini Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Upgrade Project Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Magnets Small bore / high gradient magnets required for tight control of dispersion and beta functions through the arc Challenging design, but not pushing the boundaries (other projects more aggressive) Magnet Contract placed June 2014. Delivery status: Sextupoles: in production Quadrupoles: remaking first of series magnet (first magnet not to field spec) Dipoles: first of series under-going tests Delivery expected early 2016 Courtesy R. Bartolini, C. Bailey Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Vacuum Vacuum vessels are to be a mix of copper alloy and stainless steel Cu dipole and high-heat load vessels SS elsewhere Typically 18 x 27 mm internal ellipse (cf existing vessels: SS, 38 x 82 mm octagonal) Discrete ion pump and non-evaporable getter (NEG) pumps (no NEG coating) Distributed and lumped photon absorbers Vessel contract: placed Aug 2014 Final Design Review Jan 2015 Currently in final assembly and test (Nov 2015) Delivery expected early 2016 Courtesy M. Cox Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Installation Preparation work for DDBA girder installation underway since May 2014 Restricted to shut-down periods Controls Instrumentation Area extended to accommodate new DDBA hardware Temporary cabling / racks installed for existing cell 2 hardware (ID + Front End + 3 girders) Existing infrastructure has been moved over to temporary cables New cabling for DDBA components currently being installed (complete June 2016) Girder installation / commissioning during 8 week shutdown August / September 2016 Ian Martin ESLS XXI, PSIII, (Nov 2015)

DDBA Commissioning Virtual accelerator (Tracy model via EPICS) set up for high level applications testing (MML, TuneFB, SOFB, FOFB, VEFB, RFFB, LOCO, BBA) Commissioning with beam scheduled for 20th September to 1st October Intention is to return to Standard operating mode in Run#4 2016: 900 bunches / 300 mA / εy = 8 pm.rad Fall back option to reduce beam current or εy New J02 ID installed March 2017 Mode Available from Standard 900 bunch, target 300 mA Run#4 2016 Hybrid 686 bunch+1, target 300mA Run#5 2016 156-bunch, target 135 mA Run#1 2017 Low-alpha Run#2 2017 Ian Martin ESLS XXI, PSIII, (Nov 2015)

Conclusions DDBA upgrade will be the biggest change to the Diamond storage ring since it was commissioned in 2006. R&D underpins full ring replacement. Further Diamond-I upgrades still under consideration: Decision on whether to proceed with 2nd DDBA cell for DIAD beamline Other options for DIAD include replacing a single arc sextupole with a short wiggler, or alternatively replacing a single dipole with a super- bend Work on full Diamond-II upgrade continues in parallel: Modified 4BA (DDBA cell) received most attention Other MBA cells also under being looked at (5BA, modified 6BA, …) Ian Martin ESLS XXI, PSIII, (Nov 2015)