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FLASHForward Julia Grebenyuk FLASHForward team: Alexander - - PowerPoint PPT Presentation

Nov 27, 2022 337 likes •840 views

LAOLA. Plasma wakefield acceleration: towards high-quality stable beams at FLASHForward Julia Grebenyuk FLASHForward team: Alexander Aschikhin, Christopher Behrens, John Dale, Carlos Entrena, Lars Goldberg, Julia Grebenyuk, Bernhard

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Plasma wakefield acceleration: towards high-quality stable beams at

FLASHForward‣‣

Julia Grebenyuk

FLASHForward team: Alexander Aschikhin, Christopher Behrens, John Dale, Carlos Entrena, Lars Goldberg, Julia Grebenyuk, Bernhard Hidding, Tobias Kleinwächter, Alexander Knetsch, Olena Kononenko, Vladyslav Libov, Alberto Martinez de la Ossa, Jens Osterhoff, Timon Mehrling, Halil Tarik Olgun, Charlotte Palmer, Lucas Schaper, Jan-Patrick Schwinkendorf, Matthew Streeter, Bernhard Schmidt, Steffen Wunderlich, Johann Zemella

LAOLA.

1 Tuesday, February 18, 14

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Outline

Introduction to plasma acceleration

FLASHForward‣‣

General setup and schedule Physics programme Experimental setup Summary

2 Tuesday, February 18, 14

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4th July 2012 Announcement of the Higgs discovery

LHC

3 Tuesday, February 18, 14

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Livingston chart

4 Tuesday, February 18, 14

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Synchrotron light sources Free-electron lasers Particle therapy

Accelerators for applications

5 Tuesday, February 18, 14

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Circular machines: limited by the magnetic field and synchrotron radiation Linear machines: limited by accelerating gradients in RF Gradient of 100 MV/m Limited by material breakdown

Limitations

6 Tuesday, February 18, 14

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RF - Transfer of electromagnetic energy of the waves in vacuum to kinetic energy of particles Plasma acceleration - Transfer of electromagnetic energy of laser pulse or a beam to kinetic energy of particles via a medium: plasma

RF vs. plasma

7 Tuesday, February 18, 14

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First idea of ‘collective’ acceleration 1956

8 Tuesday, February 18, 14

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First idea of ‘collective’ acceleration 1956

Idea: accelerate ions by group of electrons moving in front of them Ions are heavy

9 Tuesday, February 18, 14

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−30 −25 −20 −15 −10 −5 5 −2 −1 1 2 3 4 5

a0=1.8 x=kp

  • Norm. quantities

electron density n(x)−1 scalar potential (x) laser vector potential a(x) electric field e(x)

Tajima and Dawson, 1979 > Induce large electric fields in plasma by a laser > No material breaking > Stable, high amplitude waves > Phase velocity on the

  • rder of a speed of light

Plasma acceleration

10 Tuesday, February 18, 14

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The field gradient scales with plasma density Gradients up to 100 GeV/m The size of the accelerating structure is plasma wavelength

Courtesy of

  • T. Mehrling

Plasma acceleration

E0(V/m) ≈ 96 p ne(cm−3)

11 Tuesday, February 18, 14

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Plasma density: 2.7 x 1018 cm-3 40 TW laser with 1018W cm-2

1979 > 2006

12 Tuesday, February 18, 14

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> Laser-driven accelerators (LWPA) > Beam-driven accelerators (PWFA) > Plasma beat-wave > Self-modulation beam-driven accelerators > LWPA is limited by dephasing and pump depletion length, which limits beam quality and energy gain > Laser effjciency and stability are a challange

Plasma accelerators

13 Tuesday, February 18, 14

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> Laser-driven accelerators (LWPA) > Beam-driven accelerators (PWFA) > Plasma beat-wave > Self-modulation beam-driven accelerators > LWPA is limited by dephasing and pump depletion length, which limits beam quality and energy gain > Laser effjciency and stability are a challange

Plasma accelerators

14 Tuesday, February 18, 14

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Beam-driven plasma acceleration is based

  • n similar principle

Beam space-charge repels electrons and creates a wake

Beam-driven plasma acceleration

Courtesy of A. Martinez de la Ossa

15 Tuesday, February 18, 14

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Energy doubling of the 42 GeV SLAC beam

Blumenfeld et al, Nature 445, 741 (2006)

Beam-driven plasma acceleration

16 Tuesday, February 18, 14

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How to get the surfer on the wave?

Particle injection

17 Tuesday, February 18, 14

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External injection > tailored well-characterised beam externally injected in plasma wake

How to get the surfer on the wave?

Particle injection

18 Tuesday, February 18, 14

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Internal injection > injecting and accelerating background plasma particle Wave-breaking Controlled: > ionisation-induced > colliding laser-pulses > density transitions > magnetic-field induced External injection > tailored well-characterised beam externally injected in plasma wake

How to get the surfer on the wave?

Particle injection

19 Tuesday, February 18, 14

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Challenges: > Requires short bunches > Synchronisation > Matching, emittance conservation

External injection

  • T. Mehrling et al, Phys. Rev. ST Accel. Beams 15, 111303 (2012)

20 Tuesday, February 18, 14

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Self-injection of background plasma electrons to the wake when some particles outrun the wake Process is diffjcult to control

Final bunch quality depends strongly of the mechanism of population

  • f 6D phase-space > control of injection is crutial

Wave breaking

21 Tuesday, February 18, 14

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Energy transfer from the driver to the witness beam In standard PWFA setups transformer ratios are < 2 For ramped-current beams transformer-rations are predicted to be very high (>5)

Eacc - maximum of the accelerating field of the witness beam Edecel - maximum of the decelerating field of the drive beam

R = Eacc Edecel

Transformer ratio

  • K. V. Lotov. Efficient operating mode of the plasma wakefield accelerator. Physics of Plasmas,

12:053105, May 2005.

22 Tuesday, February 18, 14

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LAOLA at DESY

LAOLA, the Laboratory for Laser- and beam-driven plasma Acceleration is a collaboration between groups from DESY and the University of Hamburg.

http://laola.desy.de

23 Tuesday, February 18, 14

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Plasma acceleration at DESY

Courtesy of J. Osterhoff

24 Tuesday, February 18, 14

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FLASHForward

Courtesy of J. Osterhoff

25 Tuesday, February 18, 14

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DESY and FLASH

↑ 300 m

  • 2.3 km
  • 6.4 km

↑ 3.4 km

> FLASH: linear accelerator using super-conducting RF structures > Primary role: drive an FEL by high current, short, low emittance beams > Similar requirements for PWFA

26 Tuesday, February 18, 14

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FLASHForward scientific goals

> Generate and accelerate beams in PWFA; > Demonstrate high transformer ratios (>2) from the driver to the witness.

1

27 Tuesday, February 18, 14

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FLASHForward scientific goals

> Generate and accelerate beams in PWFA; > Demonstrate high transformer ratios (>2) from the driver to the witness. Explore controlled injection processes > External Injection of a secondary bunch (second bunch generated by a second laser at the FLASH source); > Second bunch accelerated by wake generated by first; > Controlled internal injection (density transitions, ionisation-induced, Trojan horse).

II 1

28 Tuesday, February 18, 14

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FLASHForward scientific goals

> Generate and accelerate beams in PWFA; > Demonstrate high transformer ratios (>2) from the driver to the witness. Explore controlled injection processes > External Injection of a secondary bunch (second bunch generated by a second laser at the FLASH source); > Second bunch accelerated by wake generated by first; > Controlled internal injection (density transitions, ionisation-induced, Trojan horse). Application of generated bunches > capture and transport of generated bunches to an undulator > FEL

II 1 III

29 Tuesday, February 18, 14

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FLASH beam

FLASH Gaussian beam 20 to 500 fs longitudinal RMS 10 microns radial RMS Energy ~1.2 GeV, 0.1% energy spread 1 μm transverse emittance, ~2.5 kA peak current Standard mode, can be used in parallel with main FLASH

30 Tuesday, February 18, 14

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FLASH beam

FLASH Gaussian beam 20 to 500 fs longitudinal RMS 10 microns radial RMS Energy ~1.2 GeV, 0.1% energy spread 1 μm transverse emittance, ~2.5 kA peak current Standard mode, can be used in parallel with main FLASH FLASH ‘triangular’ beam 60 to 200 fs length Energy ~1.2 GeV, 0.1% energy spread 1 μm transverse emittance, ~2.5 kA peak current Requires dedicated runtime Predicted high transformer ratios

Piot et al., Phys. Rev. Lett. 108, 034801 (2012)

31 Tuesday, February 18, 14

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sdasd sdasd

Phase I (2015+) > FLASH2 beamline design and installation > PWFA experiments with controlled injection techniques

FLASHForward

sdasd

32 Tuesday, February 18, 14

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Phase I (2015+) > FLASH2 beamline design and installation > PWFA experiments with controlled injection techniques

FLASHForward

Phase II (2018+) > PWFA-induced beams for applications > Installation on undulator and corresponding diagnostics

33 Tuesday, February 18, 14

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Experimental setup

> FLASH beam extraction and its transport to the interaction region; > The main interaction region (plasma cell inside the experimental chamber); > Post-plasma diagnostics to measure properties of the driver and witness bunches; > Witness beam extraction out of the plasma and transport to the undulators.

34 Tuesday, February 18, 14

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FLASHForward with gaussian driver

> Can be used in parallel with FLASH 1/2

  • peration

> Transformer ratio of ~2 > Field gradients up to 17 GV/m > Doubling of FLASH beam energy within less than 10 cm > Most of the physics programme will be done in this mode

Simulations by A. Martinez de la Ossa

FLASH Gaussian beam 20 to 500 fs longitudinal RMS 10 microns radial RMS Energy ~1.2 GeV, 0.1% energy spread 1 μm transverse emittance, ~2.5 kA peak current

35 Tuesday, February 18, 14

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> Maximum transformer ratios were predicted for beams with triangular current profiles > Simulations showed transformer ratios of ~6 > 50 GV/m peak field strength > Boosting the energy of a witness beam to ~5 GeV in less than 10 cm FLASH ‘triangular’ beam 60 to 200 fs length Energy ~1.2 GeV, 0.1% energy spread 1 μm transverse emittance, ~2.5 kA peak current

FLASHForward with triangular driver

Simulations by A. Martinez de la Ossa

36 Tuesday, February 18, 14

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SLIDE 37
  • J. Grebenyuk et all, AAC proceedings 2013, DOI:10.1016/j.nima.2013.10.054

Bulanov et al., Phys. Rev. E 58, R5257 (1998);

Density transition injection

m] µ y [

  • 40
  • 20

20 ] n [n

1 10 1 10

2

10

I [kA] 0.5 1 1.5 2

z = 5.4 mm

(a)

m] µ [ ζ

  • 200
  • 100

m] µ y [

  • 20

20 [GV/m]

z

E

  • 10

10

(b)

> When plasma density changes from high to low, the phase velocity of the wake slows down > Facilitates wave-breaking

37 Tuesday, February 18, 14

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Resulting beam: > highly-correlated longitudinal phase space > high current > normalised emittance < 10-7 m rad > energy spread < 0.5% High-brightness beam

Density transition injection

Bulanov et al., Phys. Rev. E 58, R5257 (1998);

  • J. Grebenyuk et all, AAC proceedings 2013, DOI:10.1016/j.nima.2013.10.054

38 Tuesday, February 18, 14

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ionisation-induced injection |

  • A. Martinez de la Ossa

> Radial electrical fields of the driver trigger ionisation > Injection happens in highly- localised region > Trapping potential has to be reached, which require high driver beam currents

  • A. Martinez de la Ossa, EAAC proceedings (2013)

39 Tuesday, February 18, 14

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  • A. Martinez de la Ossa et al, Phys. Rev. Lett. 111, 245003 (2013)

> Two species of gas required: > Hydrogen as low-ionisation threshold species (pre-ionised) > Helium for as high-ionisation threshold species Wakefield triggers injection

ionisation-induced injection |I

40 Tuesday, February 18, 14

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  • A. Martinez de la Ossa et al, Phys. Rev. Lett. 111, 245003 (2013)

ionisation-induced injection |I

Resulting beam: > highly-correlated longitudinal phase space > high current > normalised emittance < 10-6 m rad > energy spread <1% High-brightness beam

41 Tuesday, February 18, 14

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> Injection by use of low-power laser pulses with fs-scale which induces ionisation > Synchronisation is important

  • B. Hidding, Phys. Rev. Lett. 108, 035001 (2012)

ionisation-induced injection |II

Resulting beam: > normalised emittance < 10-6 m rad > energy spread <1% High-brightness beam

42 Tuesday, February 18, 14

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.

Scientific concept: J.Dale Technical concept: K.Ludwig

> Transversal and rotational manipulations > Aligning of electron and laser beams > ‘Trojan horse’ injection laser > Transverse interferometer for plasma diagnostics

Interaction region

43 Tuesday, February 18, 14

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Requirements: > plasma range of 1x1016 -> 5x1017 cm-3 > possibility to produce custom density profiles Concept: > three gas inlets > gas jet for controlled injection techniques Plasma generated by either > Ionisation laser

Precise tailoring of plasma profile > stable and reproducible beams

Plasma target

Scientific concept: A. Maier, L.Schaper, N.Delbos Technical concept: K.Ludwig , S.Lederer

44 Tuesday, February 18, 14

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Diagnostics driven by PWFA requirements

Scientific concept: V.Libov, C.Behrens Technical concept: K.Ludwig, M.Körfer

Beam diagnostics

45 Tuesday, February 18, 14

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Diagnostics driven by PWFA requirements Driver beam: > Broadband energy spectrometer > Transverse beam profile diagnostics

Scientific concept: V.Libov, C.Behrens Technical concept: K.Ludwig, M.Körfer

Beam driver

Beam diagnostics

46 Tuesday, February 18, 14

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Diagnostics driven by PWFA requirements Driver beam: > Broadband energy spectrometer; > Transverse beam profile diagnostics.

Scientific concept: V.Libov, C.Behrens Technical concept: K.Ludwig, M.Körfer

Beam driver Witness beam

Beam diagnostics

Witness beam: > high-resolution spectrometer; > quadrupoles and screens for profile and emittance measurements; > transition radiation spectrometers for longitudinal measurements; > cameras for ionisation beam measurements.

47 Tuesday, February 18, 14

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> Advance the field of PWFA > Explore controlled injection 2016+ > Possibility to produce fs-scale ultra-low emittance beams > High-brightness beams - very promising for applications 2018+

FLASHForward outlook

48 Tuesday, February 18, 14

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Many interesting experiments to come Exciting physics Please join us!

Thank you for your attention

http://laola.desy.de

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