regae: rf photo injector based ued at cfelpbpl.physics.ucla.edu/uesdm_2012/talks/manz...

REGAE: RF photo injector based UED at CFELStephanie Manz

MPSD, University of [email protected]

• REGAE setup & design parameters

• electron diffraction

• real space imaging

outline:

Stephanie Manz, MPSD / UHH / CFEL

Relativistic Electron Gun for Atomic Exploration

REGAE

CFEL ...

… a scientific cooperation of DESY,University of Hamburg and the Max Planck Society


Relativistic Electron Gun for Atomic Exploration

REGAEbeamline schematic:


REGAE setup

cathode and gun

parameters:

-S-band (3 GHz)-repetition rate 50 Hz-gradient up to 110 MV/m-RF pulse length: 6 s


REGAE setup

(re) buncher cavity

parameters:

-S-band (3 GHz)-gradient up to 25 MV/m


REGAE setup

synchronization


feedback

stability


Short term, rf + laser after the gun: < 50 fsLong term (46h), rf only:

Frank Mayet, Master thesis, 2012:

REGAE design parameters

beam dynamics

0 1 2 3 4 5 6 7 8 9 100

200

400

600

800

1000

1200

beam

siz

e [

m]

postion [m]

parameters:

laser spot: 7µm

laser pulse: 0.5 ps

Q = 0.16 pC

no space charge space charge

Stephanie Manz, MPSD / UHH / CFELASTRA simulation: http://www.desy.de/~mpyflo/


emittance

parameters:

laser spot: 7µm

laser pulse: 0.5 ps

Q = 0.16 pC


0 1 2 3 4 5 6 7 8 9 1010-3

10-2

10-1

100

emitt

ance

[mra

d m

m]

postion [m]



coherence length

0 1 2 3 4 5 6 7 8 9 100

5

10

15

20

25

30

35

40

45

50

cohe

renc

e le

ngth

[nm

]

postion [m]

parameters:

laser spot: 7µm

laser pulse: 0.5 ps

Q = 0.16 pC




time resolution

0 1 2 3 4 5 6 7 8 9 100

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

bunc

h le

ngth

[mm

]

postion [m]

parameters:

laser spot: 7µm

laser pulse: 0.5 ps

Q = 0.16 pC


~ 10 fs + timing jitter fromsynch. electronics


first shots of static diffraction

electron diffraction

0 100 200 300 400 500 600 700 800 900

-50

0

50

100

150

200

250

300

350

sample:

100 nm gold(poly crystalline)

detector: Andor iXon 3 EMCCD+ FOS

inte

nsity

[a.u

.]

r


single shotaverage of 40

• REGAE setup & design parameters

• electron diffraction

• real space imaging

outline:


relativistic TEM

inelastic scattering

10-1

100

101

102

103

100

101

total stopping power in tissue (ESTAR, NIST)

[MeV

cm

2 / g]

electron energy [MeV]

this example: water

but qualitatively similarfor most materials

low MeV range idealin terms of ionization

but:must also consider knock on damageand radio chemistry


relativistic TEM

elastic scattering

0,1 0,5 1 2 3

10-2

10-1

100

Si, 2.32 g/cm3

Au, 19.3 g/cm3

Cu, 8.92 g/cm3

liquid water

energy [MeV]

mea

n fr

ee p

ath

[m

]


relativistic TEM

outlook

rel. electron microscopy: advantage for sample thickness of several 100 nm

resolution will still be limited by multiple scattering effectsmagnification will still be limited by damage

go for : - magnification up to 105

- 10 to 100 electrons / nm2 for dynamic imaging - maximum repetition rare 50Hz


next steps

• measure time resolution at target position

• improve emittance

• time resolved diffraction

• implement lens system for real space imaging


DESY: Klaus Flöttmann Hossein Delsim-Hashemi Matthias Hoffmann Matthias Felber Holger Schlarb Kurt Müller Sven Lederer Markus Huening

accelerator physics, UHH:

Shima BayestehTim GehrkeFrank MayetMax Hachmann

Max Planck Research Department for Structural Dynamics, UHH:

R. J. Dwayne MillerMasaki HadaAlbert CasandrucDong-Fang ZhangJulian Hirscht

Sercan KeskinSantosh JangamStuart HayesRegis GenglerKostyantyn PichuginGerman SciainiAlexander MarxTaisuke Hasegawa

U of Toronto:Christina MuellerGustavo Moriena

regae: rf photo injector based ued at cfelpbpl.physics.ucla.edu/uesdm_2012/talks/manz...

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