Diamond Light Source Status and Diamond Light Source Status and Future ChallangesFuture Challanges

R. BartoliniDiamond Light Source Ltd

and

John Adams InstituteUniversity of Oxford

DL-RAL Joint Accelerator Workshop

20 January 2009

SummarySummary

1) Introduction to Diamond

2) Status of the 3 GeV 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

235 m

100 MeV Linac

3 GeV BoosterC = 158.4 m

3 GeV Storage RingC = 561.6 m

Experimental Hall and Beamlines

235 m

office building

peripheral labs. and

offices

future long beamlines

technical plant

Diamond LayoutDiamond Layout

Milestones and key factsMilestones and key facts

First LINAC beam (100 MeV)

First turn in booster

First turn in Storage ring

Beamline commissioning start

First users

300 mA

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

31st August 2005

21st December 2005

3rd May 2006

23rd October 2006

29th January 2007

15th September 2007

DL-RAL Joint Accelerator Workshop

20 January 2009

Diamond storage ring main parametersDiamond storage ring main parametersnon-zero dispersion latticenon-zero dispersion lattice

Energy 3 GeV

Circumference 561.6 m

No. cells 24

Symmetry 6

Straight sections 6 x 8m, 18 x 5m

Insertion devices 4 x 8m, 18 x 5m

Beam current 300 mA (500 mA)

Emittance (h, v) 2.7, 0.03 nm rad

Lifetime > 10 h

Min. ID gap 7 mm (5 mm)

Beam size (h, v) 123, 6.4 m

Beam divergence (h, v) 24, 4.2 rad

(at centre of 5 m ID)

48 Dipoles; 240 Quadrupoles;

168 Sextupoles (+ H / V orbit correctors + Skew Quadrupoles );

3 SC RF cavities; 168 BPMs

Diamond Storage RingDiamond Storage Ring

DL-RAL Joint Accelerator Workshop

20 January 2009

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:

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

Correction of linear optics with LOCOCorrection of linear optics with LOCO

((LLinear inear OOptics from ptics from CClosed losed OOrbit)rbit)

LOCO: fits quadrupoles to LOCO: fits quadrupoles to reproduce the theoretical reproduce the theoretical

closed orbit response matrixclosed orbit response matrix

circles = modelcircles = model

crosses = measuredcrosses = measured

0 50 100 150 200-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

Quad number

Str

engt

h va

riatio

n fr

om m

odel

(%

)

LOCO comparison

17th April 2008

7th May 2008 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

2.78 (2.75) nm

Energy spread

1.1e-3 (1.0e-3)

Emittance coupling

0.5%

Emittance and energy spreadEmittance and energy spreadmeasured using two X-ray pinholes camerasmeasured using two X-ray pinholes cameras

Measured emittance very close to the theoretical values confirms the optics

Emittance coupling is now routinely corrected to 0.1% with LOCO

Closest tune approach 0, rms Dy 1 mm

13 Insertion Devices operational13 Insertion Devices operational

7 IDS in Phase I

and

first ID of Phase II

were installed and commissioned in

early 2007

Beamline ID Type

I02 U23 In-vacuum

I03 U21 In-vacuum

I04 U23 In-vacuum

I06 HU64 APPLE-II

I15 SCW 3.5 T Superconducting Multipole Wiggler

I16 U27 In-vacuum

I18 U27 In-vacuum

I22 U25 In-vacuum

I07 U23 In-vacuum

I11 U22 In-vacuum

I19 U22 In-vacuum

I24 U21 In-vacuum

I04.1 30.8 mm Short ex-vacuum

• 10 in-vacuum undulators

• 1 variable polarization APPLE-II device

• 1 3.5T superconducting wiggler

• 1 short ex-vacuum

mmx 3.121231.0 radradx 4.2241.0' mmy 6.04.61.0

xx 1.0 '1.0' xx yy 1.0 '1.0' yy

Beam stability should be better than 10% of the beam size and divergence

For Diamond nominal optics (at the centre of the short straight sections)

radrady 4.041.0'

but IR beamlines will have tighter requirements

for 3rd generation light sources this implies sub-m stability

Strategies and studies to achieve sub-m stability

• identification of sources of orbit movement

• passive damping measures

• orbit feedback systems

Orbit stability requirements at DiamondOrbit stability requirements at Diamond

Ground vibrations to beam vibrationsGround vibrations to beam vibrations

Amplification factor girders to beam: H 31 (theory 35); V 12 (theory 8);

1-100 Hz

Horizontal Vertical

Long StraightStandard Straight

Long StraightStandard Straight

Position (μm)

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%)

Angle (μrad)

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%)

Significant reduction of the rms beam motion up to 100 Hz;

Higher frequencies performance limited mainly by the correctors power

supply bandwidth

Global fast orbit feedback at DiamondGlobal fast orbit feedback at Diamond

1-100 Hz

Standard Straight H

Standard Straight V

Position (μm)

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%)

Angle (μrad)

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%)

Summary of Current Machine StatusSummary of Current Machine Status

Target Achieved

Energy 3 GeV 3 GeV

Beam current 300 mA 300 mA Machine Development 250 mA User Mode

Emittance - horizontal 2.7 nm rad 2.7 nm rad - vertical 27 pm rad 4-50 pm rad ~ 27 pm in User Mode

Lifetime at 300 mA > 10 h ~ 18 h

Min. ID gap 7 mm 5-7 mm User Mode, dep. on ID

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

Higher average brightness

• Higher average current

• Constant flux on sample

Improved stability

• Constant heat load

• Beam current dependence of BPMs

Flexible operation

• Lifetime less important

• Smaller ID gaps

• Lower coupling

Top-Up motivationTop-Up motivation

BPMs block stability

• without Top-Up 10 m

• with Top-Up < 1 m

Crucial for long term sub- m stability

Top-Up operation consists in the continuous (very frequent) injection to keep the stored current constant to prevent the natural beam current decay

User-Mode OperationsUser-Mode Operations

“Standard” operation: 250 mA maximum, 2 injections/day

DL-RAL Joint Accelerator Workshop

20 January 2009

Top-Up operationTop-Up operation

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

• 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 DevicesFuture Insertion Devices

Beamline date Type

I12 Mar 094.2 T Superconducting Multipole Wiggler; contract with BINP;

Beamline extending outside diamond buliding

I20 Jun 092 x hybrid wigglers 2T, W83, construction in-house;

I07 End 09Cryogenic Permanent Magnet Undulator (U17.7) contract with

Danfysik. Will substitute the in-vacuum U23 device installed as a temporary measure.

I10 2010

Two APPLE II devices with 10 Hz polarization switching using 5-kicker scheme; engineering implications under study

2 girder changes

I13 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

I09 2011

Helical undulator + in-vac. CPMU, with “double mini-beta” optics proposed; beam dynamics implications under study.

1 or 2 girder changes

A long straight sections is divided into two by a triplet of quadrupolesto achieve double mini beta in V and a virtual focus in H for coherence applications

Pos. ‘A’

Customised optics in long straight sectionsCustomised optics in long straight sections

I13 beamlineI13 beamline

DL-RAL Joint Accelerator Workshop

20 January 2009

Low – alpha optics

Higher Harmonic Cavities

RF voltage modulation

Femto–slicing

1) shorten the e- bunch 2) chirp the e-bunch + slit or optical compression

3) Laser induced local energy-density modulation

e– bunch

Crab Cavities

Synchro-betatron kicks

There are three main approaches to generate short radiation pulses in storage rings

Ultra-short radiation pulses in a storage ringUltra-short radiation pulses in a storage ring

0 10 20 30 40 50 60 70 80 90

-10

0

10

20

30

x

y

x

(m

)

s (m)0 10 20 30 40 50 60 70 80 90

-20

0

20

40

(c

m)

Low alpha opticsLow alpha optics

dzVdf

c

RFsz /2

3

If high current effects are negligible the bunch length is

= 1.710–4; V = 3.3 MV; = 9.6 10–4 z = 2.8 mm (9.4 ps)

z depends on the magnetic lattice (quadrupole magnets) via 610

1 dsD

Lx

We can modify the electron optics to reduce

(low_alpha_optics) 10–6

z 0.3 mm (1 ps)

15.2 15.4 15.6 15.8 16 16.2 16.4 16.6

-0.2

-0.1

0

0.1

0.2

(m

)

s (m)15.2 15.4 15.6 15.8 16 16.2 16.4 16.6

-5

0

5

(c

m)

100

102

104

10-6

10-4

10-2

100

102

disp

lace

men

t P

SD

[ m

2 /Hz]

frequency [Hz]

x

y

fs=340Hz

fs = 340Hz => α1 = 3.4×10-6, σL = 1.5ps

fs = 260Hz => α1 = 1.7×10-6, σL = 0.98ps

100

102

104

10-6

10-4

10-2

100

102

disp

lace

men

t P

SD

[ m

2 /Hz]

frequency [Hz]

x

y

fs=260Hz

Machine tests with 1 ps latticeMachine tests with 1 ps lattice

ε = 34 nm.rad; κ = 0.03%

Qx = 21.137; Qy = 12.397

Future WorkFuture 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 mA) 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 and staff from Diagnostics, Controls, Operations, IDs, RF, …

DL-RAL Joint Accelerator Workshop

20 January 2009