Status of the Diamond Light Source R. Bartolini Diamond Light Source and John Adams Institute, University of Oxford ESLS XXII Workshop Grenoble, 25 November 2014
Outline Operation statistics The “ 10 years vision” exercise Conclusions ESLS XXII Workshop Grenoble, 25 November 2014
Operation statistics MTBF target of 72 h still elusive ESLS XXII Workshop Grenoble, 25 November 2014 courtesy V. Kempson
Operation statistics - 2014 Summary stats for 2014 to date with run 5 yet to finish Run Custom - 01/01/2014 To 14/11/2014. User Beam Data including beamline start up. Run Hours: 4359 Total Beam Trips: 89 Run Uptime (%) 90. 8% Unscheduled Downtime /Hrs: 398. 70 Scheduled Downtime /Hrs: 3. 38 MTBF /Hrs: 48. 98 Total Beam Delay Faults: 19 Total Other Faults: 227 MTTR /Hrs: 4. 48 ESLS XXII Workshop Grenoble, 25 November 2014 courtesy V. Kempson
Operation statistics - 2014 2 nd September: Helium leak in RF cavity 2 forced a quick cavity swap (with the spare brand new cavity – yet to be conditioned). Cancelled two weeks of users time 9 -22 September Retrieved some uptime by starting earlier in November run (at 230 m. A) ESLS XXII Workshop Grenoble, 25 November 2014 courtesy V. Kempson
Trips statistics Trips dominated by the SC RF ESLS XXII Workshop Grenoble, 25 November 2014 courtesy V. Kempson
RF trips statistics We took the following remedial actions: Probe blip: added a filter at circuit board level after the LLRF comparator to smooth out the blips IOT connection: checked all connections on IOTs (fault was in the connections on the delivered assembly) Vacuum trips: continuing with warm-ups and conditioning Drive amp chain: dispersed all parts of the faulty chain amongst the different systems ISC: started high power RF conditioning rather than DC conditioning. Focus coil: checked isolation of all coils and reworked suspicious radiation shielding IOT LLRF: changed closed-loop LLRF gain to reduce noise and reset interlock levels to allow 7 -IOT operation (still not completely tested) Filament current: Quench detector: swapped out the quench detector unit with the spare ESLS XXII Workshop Grenoble, 25 November 2014 courtesy C. Christou
… and now looking at installing a NC RF • the loss of two weeks at the start of the last run went down badly, particularly with industrial users; • general reliability of superconducting cavities has been brought into question - cavity failure is a catastrophic event putting Diamond out of action for several weeks - commonly accepted lifetime to failure of cavities is around 6 years - repair of cavity can be very slow (CLS cavity has taken 2 years) • normal conducting cavities have been considered as an option for some time - at the moment we envisage adding normal conducting cavities, not replacing superconducting cavities - normal conducting cavities will bring their own problems - removal of common modes of failure • board meeting resolved to add copper cavities sooner rather than later “the Board didn’t just approve the plan, but instructed us to go ahead” ESLS XXII Workshop Grenoble, 25 November 2014 courtesy C. Christou
e. g. EU HOM damped cavity • international collaboration, BESSY, ESRF, ALBA, … • coupler, tuner and HOMs mounted radially • requires external pumping ESLS XXII Workshop Grenoble, 25 November 2014 courtesy C. Christou
Hybrid RF straight section Install pair of EU cavities in the RF straight in place of the third SC cavity Two new cavities can be powered by existing amplifier No new breakthroughs into storage ring Cavities protected by small-bore sector valve ESLS XXII Workshop Grenoble, 25 November 2014 courtesy C. Christou
10 years vision 25 -th April – Science away day 9 -th June – Science away day Draft document on 10 Years Vision – October 2014 5 -th November: presented and discussed at the SAC ESLS XXII Workshop Grenoble, 25 November 2014
10 years vision Science driven (7 key scientific areas: biomaterials, chemistry, condensed matter, earth science, integrated structure biology, heritage, soft condensed matter) • beamline development (optics, detectors, stability, …) Machine development • reliability • stability Source development • CPMUs (in house) • DDBA • Conceptual design for Diamond II bid within next CSR – 2016; first beam >2020
Consolidate operation with low V emittance 8 pm Diamond operates with a very good control of the beam optics • Optics deviation (beta-beating) redecue to 1% level • Emittance [2. 78 - 2. 74] (2. 75) nm • Energy spread [1. 1 e-3 - 1. 0 -e 3] (1. 0 e-3) • Emittance coupling ~0. 08% achieved → vertical emittance ~ 2. 0 pm 6 mm rms vertical Diamond is currently running at reduced coupling 0. 3% (8 pm V) for users Transparent realignment of the machine to easy operation at low coupling (see M. Apollonio’s talk) ESLS XXII Workshop Grenoble, 25 November 2014
stability One beamline has been given control of the electron beam with a window of 20 um H and V to adjust for long term beam movement and static alignment Motion relative to the beam size courtesy G. Rehm Now coupling electron beam stability and photon beam stability at sample Feedback on beamline component not obvious (mirrors 1. 4 m long) Electron beam “easier” to move for small high frequencies variations
IDs Seven planned CPMU + SCU development with ASTe. C and RAL TD • • • New cooling system (already under development) In situ shimming (wish list) which will require a bench to measure both warm and cold develop cold measuring bench (use experience from Bessy, ESRF) ESLS XXII Workshop Grenoble, 25 November 2014 courtesy J. Schouten
DDBA Modifying one straight section to add an ID – DDBA cell 24 DDBA cell provide a 270 pm emittance existing DBA cell modified DDBA cell BM beamline Insertion Device ID beamline Magnets, vessel , BPM buttons contract placed now progressing reasonably well towards their FDR First magnet due by April 2015 – installation 8 weeks SD in August 2016 Beam back November 2016 (one week AP commissioning time) ESLS XXII Workshop Grenoble, 25 November 2014
Status (magnets) Even if the minimisation of the emittance is not the primary target, the tight control of dispersion and beta functions requires very strong quads T/m 2 <2000 17. 5 cm 55 T/m 25 cm 65 T/m 25 cm -14. 4 T/m 67 cm 55 T/m 25 cm -14. 4 T/m 97 cm 3. 4 m mid-cell straight Challenging designs but no showstoppers ! Other projects (e. g. ESRF) have more aggressive requirements
Diamond II DLS will produce a Conceptual Design report for Diamond II ~2016 Initial studies are based on MBA (modified 4 BA or 5 BA – 140 -270 pm) Making a strong effort to tailor the machine design to the user requirements customised optics length of the shutdown is not a settled questions yet… Most of technological choices and engineering issues are expected to be similar to the single cell DDBA Possible new are of development (wrt to DDBA) magnet design – permanent magnet – longitudinal gradient vacuum chamber design and vacuum system (antechamber - NEG) diagnostics for stability (including electron and photons) ESLS XXII Workshop Grenoble, 25 November 2014
(preliminary) SAC feedback SAC requested a clear assessment of the overall benefit of a low emittance upgrade beamline by beamline
An example: dispersive branch in I 20 (WIP) This beamline requires large horizontal divergence in order to have a large photon energy span at the sample The energy range is correlated with the angle of incidence on the polychromatic mirror (dispersive beamline) Source divergence defined by the slits opening angle in the FE if ID (wiggler) radiation fan has divergence >> than the slit opening angle Design the straight section with large electron beam divergence + use a wiggler? May prove sufficient…
Conclusions Diamond is continuously striving to provide a reliable and stable source of high brightness X-rays to users A 10 years vision is being shaped beamline upgrade optic, detectors machine upgrade reliability stability source development new IDs DDBA conceptual design for Diamond II New low emittance lattice by 202 x (0 x 1) ESLS XXII Workshop Grenoble, 25 November 2014
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