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
courtesy V. Kempson
ESLS XXII Workshop
Grenoble, 25 November 2014
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
courtesy V. Kempson
ESLS XXII Workshop
Grenoble, 25 November 2014
Operation statistics - 2014
2nd 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 mA)
courtesy V. Kempson
ESLS XXII Workshop
Grenoble, 25 November 2014
Trips statistics
Trips dominated by the SC RF
courtesy V. Kempson
ESLS XXII Workshop
Grenoble, 25 November 2014
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
courtesy C. Christou
ESLS XXII Workshop
Grenoble, 25 November 2014
… 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”
courtesy C. Christou
ESLS XXII Workshop
Grenoble, 25 November 2014
e.g. EU HOM damped cavity
• international collaboration, BESSY, ESRF, ALBA, …
• coupler, tuner and HOMs mounted radially
• requires external pumping
courtesy C. Christou
ESLS XXII Workshop
Grenoble, 25 November 2014
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
courtesy C. Christou
ESLS XXII Workshop
Grenoble, 25 November 2014
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 [1.1e-3 - 1.0-e3] (1.0e-3)
• Emittance coupling ~0.08% achieved → vertical emittance ~ 2.0 pm
6 mm rms vertical
Diamond is currently running at reduced coupling 0.3% (8pm 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 ASTeC 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)
courtesy J. Schouten
ESLS XXII Workshop
Grenoble, 25 November 2014
DDBA
Modifying one straight section to add an ID – DDBA cell
24 DDBA cell provide a 270pm 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/m2
<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
3.4m
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 4BA or 5BA – 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 I20 (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 202x (0  x  1)
ESLS XXII Workshop
Grenoble, 25 November 2014