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Laser-Plasma Acceleration in Sweden. Claes-Göran Wahlström Department of Physics, Lund University and Lund Laser Centre. Electrons. Protons. X-rays. Lund - an old city with a large university. Lund - A city with a strong accelerator future. LWFA. 3.5 GeV e -. 2.5 GeV p+.
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Laser-Plasma Acceleration in Sweden Claes-GöranWahlström Department of Physics, Lund University and Lund Laser Centre Electrons Protons X-rays
Lund - an old city with a large university
Lund - A city with a strong accelerator future LWFA 3.5 GeV e- 2.5 GeV p+ 2020
European Spallation Source - ESS Goal: Neutrons in Lund before 2020 Klystrons Ion source Neutron Instruments 2.5 GeV Proton Accelerator Investment: 1.5 B€ / ~10y Operations: 10 M€ / y Spallation Target station
ESS 2.5 GeV proton LINAC • -390 m length • -2.9 ms pulses • -2.5 GeV proton energy • -14 Hz • -5 MW average beam power • Ongoing international R&D • Mats Lindroos – Project leader
MAX IV with its 3.5 GeV LINAC FEL expansion ShortPulseFacility 3.5 GeV Linear accelerator (ca 250 m) 3 GeV Ring (528 m circ.) Electronsource 3 GHz normal conducting 100 Hz rep rate RF photo cathode gun 2 bunch compressors 3 Operation modes: Ring injection / SPF /FEL Emittance (norm): 0.4-1 mm mRad (FEL/SPF-mode) Charge: 20-100 pC (FEL/SPF-mode) Bunch length: 100 fs
Established at Lund University in 1995 Atomic Physics Combustion Physics Laboratory Astrophysics Chemical Physics LU Medical Laser Centre Laser research at MAX-lab • ~110 Scientists, incl. 14 Professors, 65 PhD. Students • European Large Scale Infrastructure since 1996 Lund High-Power Laser Facility
Lund Laser Centre – a partner in Laserlab-Europe • LASERLAB-EUROPEThe Integrated Initiative of European Laser Laboratories • The LLC provides Access to External Users
The Ultra-High Intensity Laser Physics Group Matthias Burza Guillaume Genoud Kristoffer Svensson Franck Wojda C-G W Lovisa Senje Martin Hansson Olle Lundh Anders Persson ~6% of LLC
Key Collaborators for Electron Acceleration Stuart Mangles, A. Thomas, S. Kneip, Z. Najmudin, K. Krushelnick, N. Dover, M. Bloom, M. Kaluza, C. Kamperidis et al.. Plasma Physics Group Imperial College, London, UK Brigitte Cros, K. Cassou, F. Wojda, Jinchuan JU, et al. Laboratoire de Physique des Gaz et des Plasmas (LPGP), Université Paris Sud 11, Orsay, France With the support of MaxLas, EuroLEAP and Laserlab Europe
LWFA with IC London 2005 - • 35 fs, 680 mJ Laser pulses • f/10 focusing
Laser polarization Electron beam profile Beam profile tilt º Laser polarization º LWFA of Monoenergetic Electron Beams in the First Plasma Wave Period Mangles et al. PRL 96, 215001 (2006). Electron Beam Profile • Electron Beam Profile (E > 7 MeV) elliptical • Axis of ellipse along direction of laser polarization • Electron motion in E-field of the laser increases beam divergence in direction of polarization • Electrons and laser overlap spatially
Electron beam stability - contrast ratio • Plasma Physics and Controlled Fusion 48, B83 (2006). • r = 107 • r = 106
Effect of Coma on the electron beam • flat wavefront: • e-spectrum well collimated and no variation of beam position with energy • 0.175 λ coma: • Beam divergence is increased • e-beam exhibits variation of beam position with energy, amplitude ~ 20 mrad Profile Electron spectrum Flat wavefront 0.175 λ coma
Effect of Coma on the X-ray spectrum Mangles et al.,Applied Physics Letters 95, 181106 (2009). • increasing the amplitude of coma aberration clearly increases the critical energy of the X-ray spectrum → increase oscillation amplitude from rβ = 1 ± 0.4 μm to 3 ± 1 μm
Effect of Spherical Aberration on theWavebreaking Threshold Submitted (2011)
Hollow Dielectric Waveguide CapillariesWith LPGP Orsay, Brigitte Cros et al.F. Wojdaet al., Phys. Rev. E80, 066403 (2009). L • Material: Glass • Length: 10 to 100 mm • Inner diam: 100-150 μm • Filled with H2 • Excellent matched guiding over several cm possible • Technical challenge: very sensitive to laser pointing and spot quality
Implementing Adaptive Optics in the Compressed Beam After Before
Active Pointing StabilizationG. Genoudet al. Rev. Sci. Instr.82, 033102 (2011) Target Piezo mirror 2D Photo-sensitive detector Reference beam Fast shutter FIR digital filter Labview FPGA
Electrons and X-rays from CapillariesG. Genoudet al. Submitted 2011 laser pulse, 40 fs, 700 mJ f/9 off-axis parabolic mirror Capillary, multimode Deformable mirror Magnet Lanex screen+aluminium shield CCD camera and objective Metalic filters X-ray sensitive CCD camera
Betatron X-rays from Capillaries 1. Estimation of the source positionG. Genoudet al. Submitted (2011) ? Laser focus End of X-ray source → X-ray emission stops after ~3 mm behind the laser focus
Betatron x-rays from Capillaries 2. Estimation of the source size Line-out l Detector a l s b → upper limit for the transverse source size ~7 µm
Electron Acceleration at the Lund Laser Centre 10 Hz Multi-TW laser Gas jets Quasi-monoenergetic electrons Stability studies Beam quality studies Wavebreaking studies Betatron X-rays Gas-filled dielectric capillaries Linear plasma waves over long distance Electron acceleration inside capillaries Betaton X-rays emission Plans, facilities... Tomorrow
The MAX-lab test-FEL facility Ti:Sapphire Seed laser Optical fibre Ti:Sapphire Gun laser Modulatorundulator Radiatorundulator Mono-chromator Half-chicane Chicane Gun laser Dog-leg Linac 2 Linac 1 Dump Seed laser Recirculator Gun