A Free Electron Laser Project at LNF

A Free Electron Laser Project at LNF

A Free Electron Laser Project at LNF

Massimo Ferrario

Massimo Ferrario

INFN - LNF

INFN - LNF

& the SPARC/X Team

2

SPARC/X Team

SPARC/X Team

D.

D. Alesini, S. Alesini, S. Bertolucci, M.E. Bertolucci, M.E. Biagini, R. Biagini, R. Boni, M. Boni, M. Boscolo, M. Castellano, A. Boscolo, M. Castellano, A. Clozza, G.Clozza, G. Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S.

Di Pirro, A. Drago, A. Esposito, M. Ferrario, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci,Guiducci, M. Incurvati, C.Ligi, F.

M. Incurvati, C.Ligi, F.MarcelliniMarcellini, C. Milardi, C. Milardi,,

,

,

Ricci, C. Sanelli, M. Serio, F. Sanelli, M. Serio, F. Sgamma, B.Sgamma, B.Spataro, A. Stecchi, A. Stella, F. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C.Tazzioli, C. Vaccarezza

Vaccarezza, M. Vescovi, C. Vicario, M. , M. Vescovi, C. Vicario, M. ZobovZobov (INFN /LNF)(INFN /LNF)

F. Alessandria, I.

F. Alessandria, I. BoscoloBoscolo, F. , F. BroggiBroggi, S., S.CialdiCialdi, C. , C. DeMartinisDeMartinis, D. Giove, C. , D. Giove, C. MaroliMaroli,, V.

V. PetrilloPetrillo, M. , M. RomèRomè, L. Serafini, , L. Serafini, (INFN /Milano)(INFN /Milano)

D. Levi, M.

D. Levi, M. MattioliMattioli, G. Medici, P. , G. Medici, P. Musumeci Musumeci (INFN /Roma1)(INFN /Roma1)

L.

L. CataniCatani, E. , E. ChiadroniChiadroni, A. , A. CianchiCianchi, D. , D. MoriccianiMoricciani, C. Schaerf , C. Schaerf (INFN /Roma2)(INFN /Roma2)

M. Migliorati, A.

M. Migliorati, A. MostacciMostacci,, L. L. PalumboPalumbo ((UnivUniv. La Sapienza). La Sapienza) F.

F. Ciocci, G. Ciocci, G. Dattoli, A. Dattoli, A. Dipace, A. Dipace, A. Doria, F. Flora, G.P. Doria, F. Flora, G.P. Gallerano, L. Gallerano, L. Giannessi,Giannessi, E.Giovenale, G. Messina, P.L.

E.Giovenale, G. Messina, P.L. Ottaviani, S. Ottaviani, S. Pagnutti, G. Pagnutti, G. Parisi, L. Parisi, L. Picardi, M.Picardi, M. Quattromini

Quattromini, , A. A. RenieriRenieri, G. , G. RonciRonci, C. , C. RonsivalleRonsivalle, M. , M. RosettiRosetti, E. , E. SabiaSabia, M. Sassi, A., M. Sassi, A. Torre, A. Zucchini

Torre, A. Zucchini (ENEA/FIS)(ENEA/FIS)

J. B.

J. B. RosenzweigRosenzweig, S. Reiche , S. Reiche (UCLA)(UCLA)

P. Bolton, D. Dowell, P.Emma, P.

Free Electron Laser

Free Electron Laser

High Brightness

High Brightness

e

e

-

-

beams

_beams

SPARC - SPARXINO - SPARX

SPARC - SPARXINO - SPARX

Outline

4

Synchrotron Radiation

Synchrotron Radiation

Undulator

Undulator

Radiation

Radiation

High Gain FEL

High Gain FEL

==>

==>

SASE

SASE

Seeding

Seeding

Q-SASE

Q-SASE

Free Electron Laser

6

Synchrotron Radiation

Synchrotron Radiation

†

d

t

=

t

-

t

=

2

r

b

c

g

-2

r

sin 1

( )

g

c

ª

4

r

3c

g

Pulse Duration

Pulse Duration

†

8

†

w

ª

1

1

2

d

t

ª

3

2

c

g

r

_{Cut-Off Frequency of the Spectrum}

_{Cut-Off Frequency of the Spectrum}

†

T

_o

†

w

=

2p

T

Revolution Frequency

Revolution Frequency

†

d

t

N

†

d

t

ª

4

r

3c

g

10

Undulator

11

Undulator

Undulator

Radiation

Radiation

†

b

ª

K

g

=

e ˜

B

l

2

pg

mc

†

q

=

1

g

K

£

1

The electron trajectory is inside the radiation cone if The electron trajectory is determined by the

The electron trajectory is determined by the undulator undulator field and thefield and the electron energy

12

Relativistic Mirrors

Relativistic Mirrors

†

l

=

l

g

†

l

=

l

†

l

ª

l

2

g

†

l

ª

l

2

g

1

+

K

(

)

Counter propagating pseudo-radiation

Counter propagating pseudo-radiation _{Compton back-scattered radiation Compton back-scattered radiation inin}

the moving mirror frame

the moving mirror frame

Doppler effect in the laboratory

Doppler effect in the laboratory

frame

frame

TUNABILITY

14 Due to the finite duration the radiation is not monochromatic but contains a frequency spectrum which is obtained by Fourier transformation of a truncated plane wave

†

15

†

x

_{( )}

Spectral Intensity

Spectral Intensity

16

†

P

=

e

6

_pe

c

g

_v

_˙

†

P

=

N

e

6

pe

c

g

_˙

v

†

P

=

N

e

6

pe

c

g

_˙

v

Peak power of accelerated charge:

different electrons radiate indepedently hence the total power depends linearly on the number N_e of electrons per bunch:

Incoherent Spontaneous Radiation Power:

Coherent Stimulated Radiation Power:

High Gain FEL

High Gain FEL

†

d

_g

dt

=

-e

mc

r

E

⋅

b = -

r

e

mc

r

E

⋅

b

r

Energy exchange occurs only if there is transverse motion Consider“seeding”by an external light source with wavelength

_l

18 After one wiggler period the electron sees the radiation with the same phase if the flight time delay is exactly one radiation period:

†

D

t

=

t

-

t

=

T

D

l

b

l

l

†

l

=

1

-

b

b

l

†

l

ª

l

2

g

1

+

K

(

)

In a resonant and randomly phased electron beam, nearly one half electrons absorb energy and half lose enrgy, with no net gain

The particles bunch around a phase for which there is no coupling with the radiation

19

Question: can there be a continuous energy

transfer from electron beam to light wave?

Answer: We need a Self Consistent Treatment

Newton

Lorentz Equations

Maxwell Equations

†

J

_^

†

E

_rad

,B

_w

l

/2

t>0

t=0

Optical

potential

20 †

v_p = w -j ˙

k + k_w < v//

The electron beam acts as a dielectric medium which slows down the phase velocity of the ponderomotive field compared to the average electron

longitudinal velocity. Hence resonant electrons bunch around a phase corresponding to gain.

The particles within a micro-bunch radiate coherently. The resulting strong radiationfield enhances the micro-bunching even further.

Result: collective instability, exponential growth of radiation power.

21

SASE FEL at short wavelengths require a very intense,

high quality e-beam

• FEL Parameter • Exponential growth • Gain Length

• Saturation power

• Constraint on emittance • Constraint on energy spread • Relative bandwidth † r =0.136 1 g_r J 1 / 3 B_u2 / 3l4 / 3_u r p l 3 4 u G L = ˜ ˜ ¯ ˆ Á Á Ë Ê = G L z P z P exp 9 ) ( 0

†

e

=

e

g

<

l

4

p

†

P

=

r

P

µ

N

r

g

g

<

D

22

SASE Saturation Results

TTF-FEL

DESY

98 nm

Since September 2000:

3 SASE FEL’s demonstrate saturation

LEUTL

APS/ANL

385 nm

September 2000

September 2000

VISA

ATF/BNL

840 nm

March 2001

˜

˜

¯

ˆ

Á

Á

Ë

Ê

=

L

z

P

z

P

exp

9

)

(

†

24

TTF FEL

LEUTLE

SASE Longitudinal coherence

The radiation “slips” over the electrons for a distance

N

_l

ζ

independent

processes

†

N

l

Slippage length

ª

26

SASE

28

The Quantum FEL SASE

Classical

Quantum

When the electrons emit on average

less than one photon , there are only

two

available momentum state and the device behaves like

a quantum two level

system

29 †

DJ

g

†

DJ

=

1

N

30

R. Saldin et al. in Conceptual Design of a 500 GeV e+e- Linear Collider with Integrated X-ray Laser Facility, DESY-1997-048

FEL Electron Beam Requirements:

FEL Electron Beam Requirements:

High Brightness

High Brightness

B

B

=> High Peak Current & Low

=>

High Peak Current & Low

Emittance

Emittance

†

B

_n

₌

2I

e

_n

2

B

_n

†

l

µ

s

_d

1

+

K

2

(

)

g

_g

B

B

K

_n

K

2

†

L

µ

g

K B

B

_n

n 1

(

₊

K

2

)

energy

energy

spread

spread

undulator

undulator

parameter

parameter

minimum radiation

minimum radiation

wavelength

wavelength

gain

gain

length

length

x

p

Projected Phase Space

Slice

Phase

Spaces

Projected

32 0 2 4 6 8 10 12 14 0 1 2 3

I=2.5kA

K=5

s

=0.0002

Energy [GeV]

l

[nm]

e

=1

e

=4

2 4 6 8 10 12 14 0 25 50 75 100 125 150

I=2.5kA

K=5

s

=0.0002

Energy [GeV]

en

=4

en

=1

L

[m]

34

High Brightness

36

Schematic View of the Envelope Equations

Schematic View of the Envelope Equations

r

=

I

s

2

_g

I

_e

Laminarity Parameter ==>

I

2

I

sg

+

e

s

g

s

s

g

g

s

g

g

sg

e

s

g

r

>>1

r

<<1

Laminar Beam

The

The beam undergoes

beam undergoes

two regimes

two regimes

along

along

the

the

accelerator:

accelerator

:

¢ ¢

s

+ ¢

s

g

¢

g

+

s

W

g

¢

g

=

I

2

I

sg

+

e

s

g

¢ ¢

s

+ ¢

s

g

¢

g

+

s

W

g

¢

g

=

I

2

I

sg

+

e

s

g

38

E

( )

z

=

Q

4

pe

R

L

1

-

z

L

1

-

z

L

(

)

+

A

+

z

L

z

L

(

)

+

A

Ê

Ë

Á

Á

ˆ

¯

˜

˜

=

Q

4

pe

R

L

g

(

z

,

A

)

g

= 1

g

= 5

g

= 10

A

≡

R

(

_g

L

)

L(t)

R

(t)

_D

_t

Laminar Beam-Transverse Space charge Field

x

p

Projected Phase Space

Slice

Phase

Spaces

Emittance Oscillations and Growth are driven

Emittance Oscillations and Growth are driven

by space charge differential defocusing

by space charge differential defocusing

in core and tails of the beam

40

Matching Conditions with the

Matching Conditions with the

Linac

Linac

†

¢

g

=

2

s

ˆ

I

2I

g

†

g

=

8

3

ˆ

I

2I

e

g

¢

†

s

=

0

Typical

Typical

X-FEL

X-FEL

Beam

Beam

If enth = 0.3 mm.mrad @ 1 nC I₀ =17 kA W2 @1 8 (SW acc. str.) g =¢ 50 m -1 ¤ E_acc =25 MV /m 0.1 1 10 100 I =100 A I =1 kA I =4 kA

Potential space charge emittance growth

Gas Beam

r

42

SPARC - SPARXINO - SPARX

SPARC Project

SPARC Project

7.5 +2.5

7.5 +2.5

M

M

€

€

(MIUR+INFN)

(MIUR+INFN)

R&D program towards high brightness

R&D program towards high brightness

e

e

beam

_beam

for

for

SASE-FEL

SASE-FEL

’

’

s

s

SPARX Phase I

SPARX Phase I

10 + 2.35

10 + 2.35

M

M

€

€

(MIUR+INFN)

(MIUR+INFN)

- R&D towards an X-ray FEL-SASE source

- R&D towards an X-ray FEL-SASE source

- Test Facility at 10 nm with the

- Test Facility at 10 nm with the

Daf

Da

f

ne Linac

_{ne Linac}

(

(

SPARXINO

SPARXINO

)

)

SPARX Phase II

44

SPARC

DESY

BNL

UCLA

SLAC

E

E

U

U

R

R

O

O

F

F

E

E

L

L

Under INFN responsibility

SPARC 3D CAD model

Under ENEA

responsibility

46

†

B

_n

₌

2I

e

_n

2

B

bunch compressors

bunch compressors

RF & magnetic

RF & magnetic

Pulse Shaping

Pulse Shaping

New Working Point

New Working Point

How to increase

2 15 2

10

2

m

A

I

B

=

ª

e

SPARC

SPARC

Brightness State of the Art

Brightness State of the Art

PITZ

48

Low

0 5 10 15 20 25 30 1980 1985 1990 1995 2000 enx [mmmrad] e n x [m m m ra d ] Year SLAC BOEING Thermionic injectors with sub-harmonic bunchers

BNL LANL-APEX LANL-AFEL BNL/UCLA/SLAC Photoninjectors SUMITOMO SUMITOMO

Low

Low

Emittance

Emittance

Sources

Sources

Heras

Heras

Thermionic

Thermionic

Injectors

Injectors

==>

=

=>

RF

RF

Photoinjectors

Photoinjectors

&

&

Emittance

Emittance

Compensation

Compensation

==>

==>

Pulse Shaping &

Pulse Shaping &

Emittance

Emittance

Oscillation Control

Oscillation Control

SPARC

SPARC

PITZ

50

Pulse Shaping

Pulse Shaping

52

Shaping obtained with single passage in the AO

crystal + 30 cm dispersive glass

Laser Pulse Shaping with “Dazzler” experiments

Slow Axis (mode 2) Fast Axis

(mode 1)

Acoustic wave

Brookhaven experiment layout

54

Pulse shape after amplification and compression

Emittance Oscillation Control

56

Matching Conditions with the

Matching Conditions with the

Linac

Linac

†

¢

g

=

2

s

ˆ

I

2I

g

†

g

=

8

3

ˆ

I

2I

e

g

¢

†

s

=

0

25 MV/m

150 MeV

0 0.5 1 1.5 2 2.5 3 3.5 0 2 4 6 8 1 0 Z_[m] Gun Linac rms beam size [mm]

rms norm. emittance [um]

-0.04 -0.02 0 0 . 0 2 0 . 0 4 0 0.001 0.002 0.003 0.004 0.005 0.006 z=0.23891 Pr R [m] -0.05 0 0 . 0 5 0 0.0008 0.0016 0.0024 0.0032 0.004 z = 1 . 5 Pr R [m] -0.04 -0.02 0 0 . 0 2 0 . 0 4 0 0.0008 0.0016 0.0024 0.0032 0.004 z = 1 0 pr _[ ra d] R _ [ m ] 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 -0.003 -0.002 -0.001 0 0.001 0.002 0.003 z=0.23891 R s [m ] Zs-Zb [m] 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 -0.003 -0.002 -0.001 0 0.001 0.002 0.003 Z=10 R s [m ] Zs-Zb [m] 0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 -0.003 -0.002 -0.001 0 0.001 0.002 0.003 z = 1 . 5 R s [m ] Zs-Zb [m] Final emittance = 0.4 mm

Matching onto the Local Emittance Max., “Ferrario Working Point” also adopted by

LCLS and TESLA-XFEL injectors

Optimum Injection in the Linac

58 14.5 m 1.5m 20º 1.5 m D 10.0 m 6.0 m

RF sections

Undulator

Gun Solenoids

Slice analysis of beam properties

Slice analysis of beam properties

at the

60 0 2 4 6 8 10 12 14 16 0.1 1 10 100 1.₁₀3 1.₁₀4 1.₁₀5 1.₁₀6 1.₁₀7 1.₁₀8 Z (m) P o w e r ( W )

Radiation power growth along the

Radiation power growth along the

undulator

undulator

@ 530 nm

@ 530 nm

UNDULATOR

Undulator period (cm) 2.8 Undulator parameter k 2.143 Undulator gap (mm) 9.25 # Undulator sections 6 # Undulator periods per section 78 Drift length between undulator sections (cm) 36.5 Additional quadrupole gradient (T/m) 5.438 Additional quadrupole length (cm) 8.4 FEL radiation wavelength (fundamental, nm) 499.6 Average beta function (m) 1.516 Expected saturation length (m) < 12

GENESIS simulation of the SPARC SASE-FEL

High Peak Current

62

Coherent Synchrotron Radiation (CSR)

Coherent Synchrotron Radiation (CSR)

·

·

Powerful radiation generates energy spread in bends

_{Powerful radiation generates energy spread in bends}

·

·

Causes bend-plane emittance growth

_{Causes bend-plane emittance growth}

·

·

Energy spread breaks achromatic system

_{Energy spread breaks achromatic system}

D

E

/

E

= 0

D

D

x = R

x = R

(

(

s

s

)

)

D

D

E/E

E/E

bend-plane emittance growth

bend-plane emittance growth

e

e

R

R

s

s

coherent radiation for

coherent radiation for

l

_l

_>

_>

s

_s

overtaking length:

overtaking length:

L

_L

ª

_ª

(24

(24

s

s

R

R

₎

₎

D

E

/

E

< 0

s

D

x

q

q

L

L

l

l

no SASE

no SASE

T.

T.

Limberg

Limberg

,

,

P.

P.

Piot

Piot

, et al.

, et al.

Energy Spectrum at TTF-FEL (DESY)

TraFiC

64

14.5 m

1.5m

10.0 m

6.0 m

Undulator

Gun

Solenoids

Velocity Bunching

Velocity Bunching

Longitudinal Focusing

Longitudinal Focusing

0 0.5 1 1.5 2 2.5 3 0 2 4 6 8 1 0 Z_[m] Gun Linac

rms norm. emittance [um]

beam current [kA]

-150 -100 -50 0 50 100 - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 0 . 3 D E _ [K e V ] -1500 -1000 -500 0 500 1000 - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 1 . 5 D E _ [K e V ] -4000 -2000 0 2000 4000 6000 - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 4 . 5 D E _ [K e V ] - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 1 0 B u n ch in g 1 0 Dz [mm] - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 0 . 3 B u n ch in g 1 0 Dz [mm] - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 3 B u n ch in g 1 0 Dz [mm] - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 4 . 5 B u n ch in g 1 0 Dz [mm] -4000 -2000 0 2000 4000 6000 - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 1 0 D E _ [K e V ] -3000 -2000 -1000 0 1000 2000 3000 - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 3 D E _ [K e V ] - 2-1.5 - 1-0.5 0 0.5 1 1.5 2 z = 1 . 5 B u n ch in g Dz [mm] 1 0 z p_z z

66

Magnetic and RF Compressors studies

Magnetic and RF Compressors studies

Beam Conditioning

Beam Conditioning

Seeding

Seeding

Cascading

Cascading

SPARC energy upgrade

SPARC energy upgrade

New Cathodes development

New Cathodes development

High repetition rate gun

High repetition rate gun

11 GHz accelerating structures

11 GHz accelerating structures

High resolution Diagnostic

High resolution Diagnostic

e

e

R

R

s

s

coherent radiation

coherent radiation

for

for

l

_l

_>

_>

s

_s

q

q

L

L

l

l

MAMBO

MAMBO

68

MAMBO

MAMBO

Channelling

Channeling of Charged Particles and Channeling Radiation

Channeling of Charged Particles and Channeling Radiation

(S.

(S.

Dabagov

Dabagov

et al.)

et al.)

@ Channeling

@ Channeling

e

-Atomic plane of crystal

) ~

(

1 j j_L U _E

70 ChR ChR lab 2 2 0 2

1

2

w

g

q

g

w

+

ª

g

µ

dt

dN

g

µ

P

- number of photons per unit of time

- number of photons per unit of time

- radiation power

- radiation power

For X-ray frequencies:

For X-ray frequencies:

100

100 MeV MeV electrons channeled in 105 electrons channeled in 105 mmm m Si Si (110) emit ~ 10-3 (110) emit ~ 10-3 ph/e-

ph/e-corresponding to a Photon Flux ~ 10

corresponding to a Photon Flux ~ 108 8 _ph/secph/sec

@ Channeling Radiation

E

E

@

@

2

2

g

_g

E

E

(1-cos

(1-cos

y

_y

)

)

•

Produzioni di impulsi X :

10

10

_fotoni/s

_fotoni/s

_{, durata 3 ps,}

_{monocromatici}

_{monocromatici}

tunabili nel range

20

20

keV

keV

- 1

- 1

MeV

MeV

.

Raggiungimento di

10

10

_fotoni/s

_fotoni/s

_{con spot focali all’interazione}

di

5

5

m

m

m

m

.

•

Studi di tecniche di

mammografia

(e

angiografia coronarica

)

con X monocromatici.

†

N

µ

S

f

N

N

s

=

2

⋅

10

72

La realizzazione di una immagine (su superficie 18x24 cm

La realizzazione di una immagine (su superficie 18x24 cm22_{) in tempi) in tempi}

di

di 2600 s2600 s scende a scende a 2.6 s2.6 s con con ll’’upgrade upgrade previsto su SPARC che portaprevisto su SPARC che porta il

il numnum. di fotoni a 2.5 10. di fotoni a 2.5 101111 _gg/s/s

The constrast (sensitivity to tissue density variations) goes from 8% to 0.1%, while the spatial resolution goes from 0,15 -0,3 mm to 0.01-0.015 mm. This means the capability to detect a tumor 30 times smaller in volume, i.e. a 2 year earlier detection of the tumor.

MaMBO Experiment:

MaMBO Experiment:

Mammography Monochromatic Beam Outlook

Accelerazione a plasma

Accelerazione a plasma

di pacchetti di elettroni (

di pacchetti di elettroni (

25 pC

25

pC)

)

da

da

100 MeV

100

MeV a 130

a 130 MeV

MeV

con

con

spread

spread

energetico < 5%,

energetico < 5%,

emitt

emitt

. < 1

. < 1

m

m

m, con laser non guidato (5 mm

_{m, con laser non guidato (5 mm}

acc

acc

.

.

length

length

).

).

Accelerazione con laser guidato (

Accelerazione con laser guidato (

5 cm

5 cm

) fino a 400

) fino a 400

MeV

MeV

,

,

gradienti > 5 GV/m

gradienti > 5 GV/m

.

.

F

_p

ª

50

m

m

l

_p

ª

30

-

100

m

m

e

£

g

D

n

n

l

2

p

The SPARXINO Opportunity

The SPARXINO Opportunity

1

1

GeV

GeV

Energy [GeV]

l

[nm]

I = 1

I = 1 kA

kA

K = 3

K = 3

s

s

= 0.1 %

= 0.1 %

e

e

=4

=4

e

e

=1

=1

76

SPARC Injector + DA

SPARC Injector + DA

F

F

NE Linac

_{NE Linac}

SPARXINO

SPARXINO

a 10 nm SASE FEL source at LNF

The SPARXINO Physics

78

Scientific case: new research frontiers in

• Atomic, molecular and cluster physics

• Plasma and warm dense matter

• Condensed matter physics

• Material science

• Femtosecond chemistry

• Life science

• Single Biological molecules and clusters

• Imaging/holography

†

D

E

_ª

h

D

t

Classical Vacuum

Classical Vacuum

Quantum Vacuum

Quantum Vacuum

QED test:

QED test:

Boiling the Vacuum

Boiling the Vacuum

a sizeable rate for spontaneous pair production requires extraordinary

a sizeable rate for spontaneous pair production requires extraordinary

strong electric field strengths of order or above the

strong electric field strengths of order or above the Schwinger Schwinger criticalcritical value

Quantum Vacuum

Quantum Vacuum

Perturbing field and probe light do not "mix"

Perturbing field and probe light do not "mix"

and the exiting probe photons are unchanged

and the exiting probe photons are unchanged

The perturbing field "changes" the structure of

The perturbing field "changes" the structure of

the quantum vacuum: probe light and field

the quantum vacuum: probe light and field

now "mix" and exiting photon carry

now "mix" and exiting photon carry

information on the structure of the vacuum.

information on the structure of the vacuum.

The properties of the QUANTUM VACUUM are

The properties of the QUANTUM VACUUM are

recorded in the

recorded in the polarisation polarisation state of the probe light,state of the probe light,

which has changed from linear to elliptical. This

which has changed from linear to elliptical. This

phenomenon is also called Vacuum Magnetic

phenomenon is also called Vacuum Magnetic

Birefringence

Birefringence

Classical Vacuum

Classical Vacuum

QED test:

QED test:

Vacuum Magnetic Birefringence

Vacuum Magnetic Birefringence

G.

82

•

Measurement schematic

•

Relevant requirements

– high magnetic field strength

– long optical path in the magnetic region

– high photon energy/high photon flux

– low background/high signal to noise ratio

QED test:

The SPARX Future?

The SPARX Future?

2

2

GeV

_GeV

Energy [GeV]

I = 2.5 kA

I = 2.5 kA

K = 3

K = 3

s

s

= 0.03 %

= 0.03 %

l

[nm]

e

e

=1

=1

e

e

=4

=4

84

FERMI

FERMI

40 nm ==> 10 nm ==> ?

40 nm ==> 10 nm ==> ?

MAMBO

MAMBO

2003 2004 2005 2006 2007 2008

2003 2004 2005 2006 2007 2008

2009 2010 2011 2012

2009 2010 2011 2012

TTF-II

TTF-II

6 nm

6 nm

LCLS

LCLS

0.1 nm

0.1 nm

TESLA

TESLA

X-FEL

X-FEL

0.1 nm

0.1 nm

SASE

SASE

Seeding

Angstrom

Angstrom

+

Channelling

Channelling

SPARX-I => Test Facility

SPARX-I => Test Facility

=>

=>

SPARX-II

SPARX-II

(SPARXINO)

(SPARXINO)

R&D X-FEL