development of synchrotron light sources: from …development of synchrotron light sources: from...

Development of synchrotron light sources:

from third to fourth generation

R. Bartolini

Diamond Light Source Ltd

and

John Adams Institute, University of Oxford

RREPS11

London, RHUL ,13 September 2011

Outline

• Introduction

synchrotron radiation properties and users’ requirements

• 3rd generation light sources

performance, trends and limitations

• 4th generation light sources

AP and FEL challenges

• beyond 4th generation and conclusions

Laser plasma accelerators driven light sources

RREPS11


Broad Spectrum which covers from microwaves to hard X-rays (tunable with IDs)

High Flux: high intensity photon beam

High Brilliance (Spectral Brightness): highly collimated photon beam generated by a small divergence and small size source

Polarisation: both linear and circular (with IDs)

Pulsed Time Structure: pulsed length down to

High Stability: submicron source stability in SR

Flux = Photons / ( s BW)

Synchrotron radiation properties

Brilliance = Photons / ( s mm2 mrad2 BW ) Partial coherence in SRs

Full T coherence in FELs

10s ps in SRs

10s fs in FELs

RREPS11


1992 ESRF, France (EU) 6 GeV ALS, US 1.5-1.9 GeV 1993 TLS, Taiwan 1.5 GeV 1994 ELETTRA, Italy 2.4 GeV PLS, Korea 2 GeV MAX II, Sweden 1.5 GeV 1996 APS, US 7 GeV LNLS, Brazil 1.35 GeV 1997 Spring-8, Japan 8 GeV 1998 BESSY II, Germany 1.9 GeV 2000 ANKA, Germany 2.5 GeV SLS, Switzerland 2.4 GeV 2004 SPEAR3, US 3 GeV CLS, Canada 2.9 GeV 2006: SOLEIL, France 2.8 GeV DIAMOND, UK 3 GeV ASP, Australia 3 GeV MAX III, Sweden 700 MeV Indus-II, India 2.5 GeV 2008 SSRF, China 3.4 GeV 2009 PETRA-III, D 6 GeV 2011 ALBA, E 3 GeV

3rd generation storage ring light sources

ESRF

SSRF

> 2011 NSLS-II, US 3 GeV SESAME, Jordan 2.5 GeV MAX-IV, Sweden 1.5-3 GeV TPS, Taiwan 3 GeV SOLARIS, Poland 3 GeV CANDLE, Armenia 3 GeV

3rd generation storage ring light sources

under construction or planned NLSL-II

Max-IV

RREPS11


Photon energy

Brilliance

Flux

Stability

Polarisation

Time structure

Ring energy

Small Emittance

Insertion Devices

High Current; Feedbacks

Vibrations; Orbit Feedbacks; Top-Up

Short bunches; Short pulses

Accelerator physics and technology challenges

RREPS11


The brilliance of the photon beam is determined (mostly) by the electron beam

emittance that defines the source size and divergence

Brilliance and low emittance

''

24 yyxx

fluxbrilliance

2

,

2

, ephexx

2

,

2

,'' ' ephexx

2

xxxx )D(

2

xxx'x )'D(

ESRF

APS SPring8

ALS

ELETTRA

PLS

MAX-II

BESSY-II

SLS

CLS

SPEAR3

SAGA-LS ASP

Diamond SOLEIL

SSRF

PETRA-III

ALBA

CANDLE

Max-IV NSLS-II

TPS

0

4

8

12

16

20

0 1 2 3 4 5 6 7 8 9

Em

itta

nc

e (n

m)

Energy (GeV)

Brilliance with IDs

Medium energy storage rings with In-vacuum undulators operated at low gaps (e.g.

5-7 mm) can reach 10 keV with a brilliance of 1020 ph/s/0.1%BW/mm2/mrad2

Thanks to the progress with IDs technology storage ring light sources can cover

a photon range from few tens of eV to tens 10 keV or more with high brilliance

RREPS11


Diamond aerial view

Diamond is a third generation light source open for users since January 2007

100 MeV LINAC; 3 GeV Booster; 3 GeV storage ring

2.7 nm emittance – 300 mA – 18 beamlines in operation (12 in-vacuum small gap IDs)

Diamond storage ring main parameters non-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 mm

Beam divergence (h, v) 24, 4.2 mrad (at centre of 5 m ID)

IoP NPPD

Glasgow, 06 April 2011

48 Dipoles; 240 Quadrupoles; 168 Sextupoles (+ H

and V orbit correctors + Skew Quadrupoles ); 3 SC

RF cavities; 168 BPMs

Quads + Sexts have independent power supplies

All BPMS have t-b-t- capabilities

Linear optics modelling and correction

0 100 200 300 400 500 600-1

-0.5

0

0.5

1

S (m)

Hor.

Beta

Beat

(%)

0 100 200 300 400 500 600-2

-1

0

1

2

S (m)

Ver.

Beta

Beat

(%)

Hor. - beating < 1% ptp

Ver. - beating < 1 % ptp

Very good control of the linear optics with LOCO

Emittance [2.78 - 2.74] (2.75) nm

Energy spread [1.1e-3 - 1.0-e3] (1.0e-3)

Coupling correction to below 0.1%

V beam size at source point 6 μm

V emittance 2.2 pm

Top-Up mode

17th-19th September 2009: 112 h of uninterrupted beam:

25th January 2011 first full operating week (144 hours )

0.64%

t = 26 h

RREPS11


dzVdf

c

RFs

z/2

3

Short bunches at Diamond

(low_alpha_optics) (nominal) /100

6101 ds

D

L

x

z(low alpha optics) z(nominal)/10

We can modify the electron optics to reduce

The equilibrium bunch length at low current is

Comparison of measured pulse length for

normal and low momentum compaction

2.5 ps is the resolution of the streak camera

Shorter bunch length confirmed by synchrotron tune measurements

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

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

I09 and I13: “Double mini-beta” and Horizontally

Focusing Optics

I13 October 2010

I09 April 2011

4 new

quadrupoles

new mid-straight girder

existing

girders

modified

in-vacuum undulators

Trends in 3rd generation light sources

Striving to meet advanced user’s requirements

more beamlines (canted undulator from single straight sections)

customised optics

higher brightness (low emittance – low coupling)

higher flux (higher current)

short pulses

New machine designs or upgrades are targeting 100 pm or less in the horizontal plane

… but peak brightness, transverse coherence and pulses length cannot compete with FELs

RREPS11


Transverse coherence

Users’ requirements - 4th generation light sources

SASE

direct seeding - seeding + HG Temporal coherence

High repetition rates / Time structure SC/NC RF

Polarisation control

Synchronisation to external lasers VUV and THz

Ultra short pulses (<100 fs down to sub-fs)

IDs technology or novel schemes

Tunability

Higher peak brightness

Many projects target Soft X-rays (here 40 – 1 nm) . Soft X-rays FELs require 1-3 GeV

Linacs. Hard X-rays project will also provide Soft X-rays beamlines (Swiss FEL – LCLS)

FEL radiation properties

FELs provide peak brilliance 8 order of magnitudes larger than storage ring light sources

Average brilliance is 2-4 order of magnitude larger and radiation pulse lengths are of the order of 100s fs or less

Slicing or low charge

X-rays FELs

FLASH 47-6.5 nm 1 GeV SC L-band 1MHz (5Hz) SASE

FERMI 40-4 nm 1.2 GeV NC S-band 50 Hz seeded HGHG

SPARX 40-3 nm 1.5 GeV NC S-band 100 Hz SASE/seeded

Wisconsin 1 nm 2.2 GeV SC/CW L-band 1 MHz seeded HHG

LBNL 100-1 nm 2.5 GeV SC/CW L-band 1 MHz seeded

MAX-LAB 5-1 nm 3.0 GeV NC S-band 200 Hz SASE/seeded

Shanghai 10 nm 0.8-1.3 GeV NC S-band 10 Hz seeded HGHG

NLS 20-1 nm 2.2 GeV SC/CW L-band 1-1000 kHz seeded HHG

LCLS 0.15 nm 14 GeV S-band 120 Hz SASE

SACLA 0.1 nm 8 GeV C-band 60 Hz SASE

XFEL 0.1 nm 17.5 GeV SC L-band CW (10 Hz) SASE

Swiss-FEL 0.1 nm 5.8 GeV C-band 120 Hz SASE

Swiss-FEL 10 nm 2.1 GeV NC S-band 120 Hz SASE/seeded

LCLS-II 4 nm 4 GeV NC S-band 120 Hz seeded

LCLS lasing at 1.5 Å (April 2009)

NLS Conceptual Design Report (May 2010)

The science case requires a light source with

• photon energies from THz to X-rays

• high brightness

• high repetition rate (1 kHz to 100 kHz or more)

• short pulses: 1011 ppp - 20 fs upgrade to sub-fs pulses

• full coherence

The technical solution proposed is based on a combination of advanced conventional lasers and FELs

• 2.25 GeV SC linac

• seeded harmonic cascaded FEL (50 eV to 1 keV)

RREPS11


photoinjector

3rd harmonic cavity

BC

1

BC2 BC3

laser heater accelerating modules

collimation

diagnostics

spreader

FELs

IR/THzundulators

gas filters

experimental stations

UK New Light Source (NLS)

High brightness electron gun operating (initially) at 1 kHz

2.25 GeV SC CW linac L- band

50-200 pC

3 FELS covering the photon energy range 50 eV – 1 keV (50-300; 250-800; 430-1000)

• GW power level in 20 fs pulses

• laser HHG seeded for temporal coherence

• cascade harmonic FEL • synchronised to conventional lasers (60 meV – 50 eV) and IR/THz sources for pump

probe experiments

Accelerator Physics Challenges

MEASURED SLICE EMITTANCE at 20 pC

Managing collective effects with high brightness beams is a non trivial AP task

Optimisation validate by full start to end simulations from Gun to FEL

CSR effects at BC2

Seeding improves

longitudinal coherence shorter saturation length

stability (shot to shot power, spectrum, ...) control of pulse length

allows synchronisation to external lasers

FEL physics challenges: need for seeding

Advantage of seeded operation vs SASE

SASE has a very spiky output: each cooperation length behaves independently:

no phase relation among spikes

SASE t >> 1 Seeded t ~ few TFL

Seed source are not available down to 1 keV. Frequency up-conversion done with

FEL itself (HGHG, HGHG cascade, EEHG most unproven yet)

FEL physics challenges: harmonic cascade

Optimisation of cascaded harmonic FEL for highest power and highest contrast ratio

Conflicting requirements:

generate bunching at higher harmonics of interest

keep the induced energy spread low

Courtesy N. Thompson

u,seed n

2

seed2u,

2but

Sub-fs radiation pulses

Slicing +

wavelength

Slicing +

current

Slicing +

Energy chirp

Single

spike

Mode-

Locking

Pulse length 300 as 250 as 200 as

or less 300 as

23 as

every 150 as

Photon energy 12 keV 12 keV 12 keV 12 keV 8.6keV

Photon per pulse 108 109 1010 108 108

Peak Power 5 GW 50 GW 100 GW 5 GW 5 GW

contrast poor poor good excellent good

Rep rate Laser seed Laser

seed Laser seed LINAC Laser seed

synchronisation YES YES YES NO YES

• laser slicing (Zholents, Saldin, Fawley)

• mode locking (Thompson, McNeil)

• single spike (Bonifacio, Pellegrini)

• echo – based (Xiang –Huang-Stupakov)

Generation of sub-fs radiation pulses has been proposed with a variety of mechanisms

e-beam ~ 100 fs

)t(E

Possible future directions for 4th generation

light sources

• Ultracold injectors: low emittance, low charge, to shorten the saturation length

• Insertion Devices: development of new undulators beyond Apple-II, compact,

shorter periods, higher fields, wakefield control, compact (e.g. Superconducting U)

• RF: Optimise performance and reduce cost of SC RF (gradient choices 13-15

MV/m for LBNL, NLS, BESSY) or use simple low risk design with high gradient (possibly high repetition rate based on C-band X-band)

• FEL physics: Critical assessment of various seeding schemes, non-seeding and

slicing options, HHG, HGHG cascade and sub fs pulses

• AP Physics: alternative compression schemes to avoid the limits posed by

microbunching (velocity bunching)

• Diagnostics: New diagnostics for ultra short bunches, arrival time, low charge but

also dealing with COTR

• Timing and synhcronisation: sub 10-fs resolution over 100s m; long term stability

• Stability and feedbacks: positions (sub mm over large frequency range), energy,

charge, …

The progress with laser plasma accelerators in the last years have open the

possibility if using them for the generation for synchrotron radiation and even to drive

a FELs

First observation of undulator radiation achieved in Soft X-ray

FEL type beam can be achieved with relatively modest improvements on what

presently achieved and significant improvement on the stability of these beams

Beyond fourth generation light sources

Layout of a compact light source

driven by a LPWA

LBNL-Oxford experiment (2006)

W. P. Leemans et al. Nature Physics 2 696 (2006) E = 1.0 +/-0.06 GeV

ΔE = 2.5% r.m.s

Δθ = 1.6 mrad r.m.s.

Q = 30 pC charge

Capillary: 310 μm

Laser: 40 TW

Density: 4.3 ×1018 cm-3

Density 4.3 1018 cm–3

Laser Power > 38 TW (73 fs) to 18 TW (40 fs)

Laser plasma wakefield accelerators demonstrated the possibility of generating

GeV beam with promising electron beam qualities

RREPS11


Undulator radiation from LPWA

First combination of a laser-plasma wakefield accelerator, producing 55–75MeV

electron bunches, with an undulator to generate visible synchrotron radiation

Undulator radiation Soft Xrays

MPQ experiment

22

2

2

u

2

K1

2

Spontaneous undulator radiation and

off-axis dependence

M. Fuchs et al, Nature Physics (2009)

Electron spectrum

radiation spectrum

Undualtor radiation Soft Xrays – MPQ experiment

Stability of the electron beam quality is crucial for a successful FEL operation

RREPS11


Alpha - X Project

Courtesy M. Wiggins

RREPS11


Diagnostics development

Can LPWA beam drive a Free Electron Laser (e.g. in the Soft X-rays) ?

Activity on diagnostics to characterise such electron pulses

Energy - Energy spread – Emittance - Pointing stability

Courtesy M. Wiggins

125 MeV - divergence 2-4 mrad - Average emittance 2 um – best emtittance 1 um

Resolution limted

Beam quality close to lasing requirements

RREPS11


Users’ requirements pose difficult challenges for storage ring and FEL design and

operation

The methods and solutions developed show that these challenges can be met.

Experimental tests of seeding in the coming future will confirm the extent of seeding

capabilities to cover the whole Soft X-ray spectrum down to 1 nm

However, more compact and economic solutions to meet the present challenges

are needed:

Injectors – IDs – LINACs RF technology …. LPWA

Conclusions

Thank you for your attention.

RREPS11


development of synchrotron light sources: from …development of synchrotron light sources: from...

Documents