Laser driven plasma wakefield accelerators and radiation sources · 2017. 9. 7. · ALPHA-X...

ELI Bucharest 2011ALPHA-X [email protected]

Laser driven plasma wakefield accelerators and radiation

sources

Dino JaroszynskiUniversity of Strathclyde


Outline of talk• Large and small accelerators + high power lasers• Laser driven wakes• Ultra-short bunch electron production using wakefield

accelerators • Betatron gamma ray source• Conclusion


CERN – LHC27 km circumference

SLAC

50 GeV in 3.3 km

20 MV/m

7 TeV in 27 km

7 MV/m

Large accelerators depend on superconducting Radio Frequency cavities


Synchrotrons light sources and free-electron lasers: tools for scientists

Synchrotron – huge size and cost is determined by accelerator technology

Diamond

undulatorsynchrotron

DESY undulator


Particles accelerated by electrostatic fields of plasma waves

Accelerators:

Surf a 10’s cm long microwave –conventional technology

Surf a 10’s mm long plasma wave –laser-plasma technology

2

max

23

gagg ª

[V/cm]E e nª


Wakefield acceleration

lp

Dephasing length: which gives a maximum energy:

0g

p

wgw

=

204 3 ,d g pL c ag w=

20

23 g

ag gª


Bubble structure – relativistic regime

laser

self-injected electron bunch undergoing betatron oscillations

ion bubble

0

2paR

lªion bubble radius


ALPHA-X started in 2002 Advanced Laser Plasma High-energy Accelerators towards X-rays

Compact femtosecond duration particle, synchrotron, free-electron laser and gamma ray source l = 2.8 nm – 1 mm (


ALPHA-X all-optical injection experiments on ASTRA

800 nm

350 – 540 mJ

40 fs

F/16 mirror

gg ≈ 10

1018 Wcm-2 in 25 mm spot

a0 ~ 0.7 – 1

ne~ 1.5 x 1019cm-3

S. Mangles et al. Nature 2004

3%dgg

ª

ALPHA-X: Imperial/RAL/Strathclyde

t ~ 5 – 10 fsI ~ 5 kA

Few fs duration electron bunch

20

max

2150

3gagg = ª


LBNL - Oxford campaign (ALPHA-X) team: GeV beams from capillary

Pre-formed plasma channels –Spence & Hooker (PRE 2001)

W. Leemans, … S. Hooker, (Nature Physics 2006)

ALPHA-X: Oxford & Berkeley

Channels manufactured using laser machining techniques – Jaroszynski et al., (Royal Society Transactions, 2006)


1 GeV beams

50 pC 30 pC

Acceleration to 1 GeV in 33 mm long pre-formed plasma channels

5% shot-to-shot fluctuations in mean energy

W. Leemans, … S.Hooker, (Nature Physics 2006)

E = 0.48 GeV±6% and an r.m.s. spread


210

BENDINGMAGNET

UNDULATOR

ELECTRON ENERGYSPECTROMETER

LASER IN

PLASMA ACCELERATOR

RADIATIONSPECTROMETER

Strathclyde: ALPHA-X beam line

8 m

TOPS laser:1.1 J @ 10 Hzl = 800 nm30 fs

Jaroszynski et al., (Royal Society Transactions, 2006)


Experimental Results – energy stability

Electron Spectrometer: 200 consecutive shots (spectrum on 196 shots)

69 90 124 185Energy (MeV)

100 consecutive shotsMean E0 = (137 ± 4) MeV

2.8% stability


Energy spread at 130 MeV

100 110 120 130 140 150

8000

10000

12000

14000

16000

18000

Char

ge/u

nit e

nerg

y [a

.u.]

Energy [MeV]

0.75%gsg

=

63 MeV 170 MeV

130 135 140 145 1500

5

10

15

20

25

30

Coun

ts

Energy [MeV]

r.m.s. spread of mean energy 2.8%


-0.75 -0.50 -0.25 0.00 0.25 0.50 0.75

-3

-2

-1

0

1

2

3

4

x' [m

rad]

x[mm]

Experimental Results – emittance

• divergence 1 – 2 mrad for this runwith 125 MeV electrons

• average eN = (2.2 ± 0.7)p mm mrad• best eN = (1.0 ± 0.1)p mm mrad• Elliptical beam: eN, X > eN, Y

• Second generation mask with hole f ~ 25 mm and improved detection system

0 1 2 30

5

10

Coun

t

enx [p mm mrad]

(a)

0 1 2 30

5

10

Coun

t

eny [p mm mrad]

(b)


Ultra-short pulseMeasurements at Strathclyde indicate 1-2 fs electron bunches with

1-10 pC: i.e. Multi kA peak current, with energy spread and emittance – suitable for FEL


Synchrotron radiation from an ion channel wiggler: betatron radiation

• Wiggler motion – electron deflection angle q ~(px/pz) is much larger than the angular spread of the radiation j=(1/γ)

• Only when k & p point in the same direction do we get a radiation contribution.

• Spectrum rich in harmonics – peaking at• Radiation rate therefore only emission at dephasing length

1uag >> >>

deflection angle – au /g

j=1/g

338

ucrit

ah ª2W gµ dL


SCALING LAWS

• Betatron Frequency: • Transverse momentum:• Divergence: • Critical photon Energy:• Efficiency:

• Wavelength:

/ 2pbw w g=

ea n rb bgµ

/abJ g=2

c eE n rbgµ

Betatron radiation emission during LWFA

/phot cycleN aba=

2 22 2

2 3/231 ( ) 1 ( )

2 2 2h e ee p e

a ach h

b b bl pl g j g jg w g

Ê ˆ Ê ˆ= + + = + +Á ˜ Á ˜

Ë ¯ Ë ¯


Gamma Ray Source demoistrated on Gemini using PW laser108 photons between .1 and 7 MeVBrilliance 1023 photons/(s mrad2 mm2 0.1%bandwidth) is

femtosecond duration pulses


Typical high energy spectra: Gemini experiment using plasma channel 85% of shots


Synchrotron, betatron and FEL radiation peak brilliance

ALPHA-X ideal 1GeV bunch

FEL: Brilliance 5 – 7 orders of magnitude larger

lu = 1.5 cm

en = 1 p mm mrad

te = 10 fs

Q = 100 – 200 pC

I = 25 kA

dg/g < 1%

I(k) ~ I0(k)(N+N(N-1)f(k)) FEL = spontaneous emission x 107

betatron source


The Scottish Centre for the Application of Plasma Based Accelerators: SCAPA

1000 m2 laboratory space: 200-300 TW laser and 10 “beam lines” producing particles and radiation sources for applications: nuclear physics, health sciences, plasma physics, homeland security etc.

New £100m Strathclyde Technology Innovation Centre


Strathclyde (students and staff):Team: Dino Jaroszynski, Salima Abu-Azoum, Maria-Pia Anania, ConstantinAniculaesei, Rodolfo Bonifacio, Enrico Brunetti, Sijia Chen, Silvia Cipiccia, David Clark, Bernhard Ersfeld, John Farmer, David Grant, Ranaul Islam, Riju Issac, Yevgen Kravets, Tom McCanny, Grace Manahan, Adam Noble, Guarav Raj, Richard Shanks, Anna Subiel, Xue Yang, Gregory Vieux, Gregor Welsh and Mark WigginsCollaborators: Gordon Rob, Brian McNeil, Ken Ledingham and Paul McKenna

ALPHA-X: Current and past collaborators:ELI-NP Bucharest, Lancaster U., Cockcroft Institute / STFC - ASTeC, STFC – RAL CLF, U. St. Andrews, U. Dundee, U. Abertay-Dundee, U. Glasgow, Imperial College, IST Lisbon, U. Paris-Sud - LPGP, Pulsar Physics, UTA, CAS Beijing, LBNL, FSU Jena, U. Stellenbosch, U. Oxford, LAL, U. Twente, TUE, U. Bochum, ....

ALPHA-X project

Current Support:

EPSRC, E.U. Laserlab, STFC

consortium


FIN

Thank you

Laser driven plasma wakefield accelerators and radiation sources��Outline of talkCERN – LHC�27 km circumferenceSynchrotrons light sources and free-electron lasers: tools for scientistsParticles accelerated by electrostatic fields of plasma wavesWakefield accelerationBubble structure – relativistic regimeALPHA-X started in 2002 �Advanced Laser Plasma High-energy �Accelerators towards X-raysALPHA-X all-optical injection experiments on ASTRALBNL - Oxford campaign (ALPHA-X) team: GeV beams from capillary1 GeV beamsSlide Number 12Slide Number 13Energy spread at 130 MeVSlide Number 15Ultra-short pulseSlide Number 18Slide Number 19Gamma Ray Source demoistrated on Gemini using PW laserTypical high energy spectra: Gemini experiment using plasma channel 85% of shotsSynchrotron, betatron and FEL radiation peak brillianceThe Scottish Centre for the Application of Plasma Based Accelerators: SCAPASlide Number 26FIN��Thank you

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Laser driven plasma wakefield accelerators and radiation sources · 2017. 9. 7. · ALPHA-X...

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