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

2. 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)

3. 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
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 /
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

4. 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)

5. 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)

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

7. 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)

8. 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)

9. 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)

10. 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
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)

11. 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)

12. 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)

13. 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)

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

15. 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 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)

16. 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)

17. 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)

18. 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#
Hybrid 686 bunch+1, target 300mA
Run#
156-bunch, target 135 mA
Run#
Low-alpha
Run#
Ian Martin
ESLS XXI, PSIII, (Nov 2015)

19. Conclusions
DDBA upgrade will be the biggest change to the Diamond storage ring since it was commissioned in 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)