1
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Beier NF, Allison H, Efthimion P, Flippo KA, Gao L, Hansen SB, Hill K, Hollinger R, Logantha M, Musthafa Y, Nedbailo R, Senthilkumaran V, Shepherd R, Shlyaptsev VN, Song H, Wang S, Dollar F, Rocca JJ, Hussein AE. Homogeneous, Micron-Scale High-Energy-Density Matter Generated by Relativistic Laser-Solid Interactions. PHYSICAL REVIEW LETTERS 2022; 129:135001. [PMID: 36206410 DOI: 10.1103/physrevlett.129.135001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/01/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Short-pulse, laser-solid interactions provide a unique platform for studying complex high-energy-density matter. We present the first demonstration of solid-density, micron-scale keV plasmas uniformly heated by a high-contrast, 400 nm wavelength laser at intensities up to 2×10^{21} W/cm^{2}. High-resolution spectral analysis of x-ray emission reveals uniform heating up to 3.0 keV over 1 μm depths. Particle-in-cell simulations indicate the production of a uniformly heated keV plasma to depths of 2 μm. The significant bulk heating and presence of highly ionized ions deep within the target are attributed to the few MeV hot electrons that become trapped and undergo refluxing within the target sheath fields. These conditions enabled the differentiation of atomic physics models of ionization potential depression in high-energy-density environments.
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Affiliation(s)
- N F Beier
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - H Allison
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - P Efthimion
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - K A Flippo
- Los Alamos National Laboratory, P.O. Box 1163, Los Alamos, New Mexico 87545, USA
| | - L Gao
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - S B Hansen
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - K Hill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - R Hollinger
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - M Logantha
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - Y Musthafa
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - R Nedbailo
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - V Senthilkumaran
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - R Shepherd
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - V N Shlyaptsev
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - H Song
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - S Wang
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - F Dollar
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - J J Rocca
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
- Department of Physics, Colorado State University, Fort Collins, Colorado 80521, USA
| | - A E Hussein
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
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2
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Gambari M, Clady R, Videau L, Utéza O, Ferré A, Sentis M. Experimental investigation of size broadening of a K α x-ray source produced by high intensity laser pulses. Sci Rep 2021; 11:23318. [PMID: 34857801 PMCID: PMC8640065 DOI: 10.1038/s41598-021-02585-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/15/2021] [Indexed: 11/08/2022] Open
Abstract
The size of a hard Kα x-ray source ([Formula: see text] = 17.48 keV) produced by a high intensity femtosecond laser interacting with a solid molybdenum target is experimentally investigated for a wide range of laser intensity (I ~ 1017-2.8 × 1019 W/cm2) and for four values of the temporal contrast ratio (6.7 × 107 < CR < 3.3 × 1010). Results point out the size enlargement of the x-ray source with the increase of laser intensity and with the deterioration of temporal contrast. It amounts up to sixteen times the laser spot size at the highest laser intensity and for the lowest temporal contrast ratio. Using hydrodynamic simulations, we evaluate the density scale length of the pre-plasma L/λ just before the main pulse peak. This allows us to show that a direct correlation with the laser absorption mechanisms is not relevant to explain the large size broadening. By varying the thickness of the molybdenum target down to 4 µm, the impact of hot electron scattering inside the solid is also proved irrelevant to explain the evolution of both the x-ray source size and the Kα photon number. We deduce that the most probable mechanism yielding to the broadening of the source size is linked to the creation of surface electromagnetic fields which confine the hot electrons at the solid surface. This assumption is supported by dedicated experiments where the evolution of the size enlargement of the x-ray source is carefully studied as a function of the laser focal spot size for the highest contrast ratio.
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Affiliation(s)
- M Gambari
- LP3, CNRS, Aix Marseille Université, 13288, Marseille, France.
| | - R Clady
- LP3, CNRS, Aix Marseille Université, 13288, Marseille, France
| | - L Videau
- CEA, DAM, DIF, 91297, Arpajon, France
- Laboratoire Matière Conditions Extrêmes, CEA, Université Paris-Saclay, 91680, Bruyères-le-Châtel, France
| | - O Utéza
- LP3, CNRS, Aix Marseille Université, 13288, Marseille, France
| | - A Ferré
- LP3, CNRS, Aix Marseille Université, 13288, Marseille, France
| | - M Sentis
- LP3, CNRS, Aix Marseille Université, 13288, Marseille, France.
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3
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Afshari M, Krumey P, Menn D, Nicoul M, Brinks F, Tarasevitch A, Sokolowski-Tinten K. Time-resolved diffraction with an optimized short pulse laser plasma X-ray source. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2020; 7:014301. [PMID: 31934600 PMCID: PMC6941949 DOI: 10.1063/1.5126316] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 12/16/2019] [Indexed: 06/07/2023]
Abstract
We present a setup for time-resolved X-ray diffraction based on a short pulse, laser-driven plasma X-ray source. The employed modular design provides high flexibility to adapt the setup to the specific requirements (e.g., X-ray optics and sample environment) of particular applications. The configuration discussed here has been optimized toward high angular/momentum resolution and uses K α -radiation (4.51 keV) from a Ti wire-target in combination with a toroidally bent crystal for collection, monochromatization, and focusing of the emitted radiation. 2 × 10 5 Ti-K α1 photons per pulse with10 - 4 relative bandwidth are delivered to the sample at a repetition rate of 10 Hz. This allows for the high dynamic range (104) measurements of transient changes in the rocking curves of materials as for example induced by laser-triggered strain waves.
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Affiliation(s)
- M Afshari
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - P Krumey
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - D Menn
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - M Nicoul
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - F Brinks
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - A Tarasevitch
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
| | - K Sokolowski-Tinten
- Faculty of Physics and Center for Nanointegration Duisburg-Essen, University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany
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4
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Stoeckl C, Filkins T, Jungquist R, Mileham C, Pereira NR, Regan SP, Shoup MJ, Theobald W. Characterization of shaped Bragg crystal assemblies for narrowband x-ray imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10G124. [PMID: 30399777 DOI: 10.1063/1.5036525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
X-ray imaging using shaped crystals in Bragg reflection is a powerful technique used in high-energy-density physics experiments. The characterization of these crystal assemblies with conventional x-ray sources is very difficult because of the required angular resolution of the order of ∼10 μrad and the narrow bandwidth of the crystal. The 10-J, 1-ps Multi-Terawatt (MTW) laser at the Laboratory for Laser Energetics was used to characterize a set of Bragg crystal assemblies. The small spot size (of the order of 5 μm) and the high power (>1018 W/cm2) of this laser make it possible to measure the spatial resolution at the intended photon energy. A set of six crystals from two different vendors was checked on MTW, showing an unexpectedly large variation in spatial resolution of up to a factor of 4.
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Affiliation(s)
- C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - T Filkins
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - R Jungquist
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - C Mileham
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - N R Pereira
- Ecopulse, Inc., 7844 Vervain Ct., Springfield, Virginia 22152, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - M J Shoup
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
| | - W Theobald
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299, USA
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5
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Li C, Liao GQ, Zhou ML, Du F, Ma JL, Li YT, Wang WM, Sheng ZM, Chen LM, Zhang J. Backward terahertz radiation from intense laser-solid interactions. OPTICS EXPRESS 2016; 24:4010-4021. [PMID: 26907053 DOI: 10.1364/oe.24.004010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report a systematic study on backward terahertz (THz) radiation generation from laser-solid interactions by changing a variety of laser/plasma parameters. We demonstrate a high-energy (with an energy flux density reaching 80 μJ/sr), broadband (>10 THz) plasma-based radiation source. The radiation energy is mainly distributed either in the >10 THz or <3 THz regions. A radial surface current formed by the lateral transport of low-energy electrons (LEE) is believed to be responsible for the radiation in the high-THz region (>10 THz), while high-energy surface fast electrons (SFE) accelerated along the target surface mainly contribute to lower frequency (<3 THz) radiation. The unifying explanation could be applied to backward THz radiation generation from solid targets with presence of relative small preplasmas.
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6
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Valdivia MP, Stutman D, Stoeckl C, Theobald W, Mileham C, Begishev IA, Bromage J, Regan SP. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023505. [PMID: 26931847 DOI: 10.1063/1.4941441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/24/2016] [Indexed: 06/05/2023]
Abstract
X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 10(23) cm(-3) in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. The 50 ± 15 μm spatial resolution achieved across the full field of view was found to be limited by the x-ray source-size, similar to conventional radiography.
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Affiliation(s)
- M P Valdivia
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - D Stutman
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - W Theobald
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C Mileham
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - I A Begishev
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - J Bromage
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - S P Regan
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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7
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He W, Zhao Z, Wang J, Zhang B, Qian F, Yang Z, Shui M, Lu F, Teng J, Cao L, Gu Y. Blind deconvolution for spatial distribution of Kα emission from ultraintense laser-plasma interaction. OPTICS EXPRESS 2014; 22:5875-5882. [PMID: 24663925 DOI: 10.1364/oe.22.005875] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The spatial distributions of the Kα emission from foil targets irradiated with ultra-intensity laser pulses have been studied using the x-ray coded imaging technique. Due to the effect of hard x-ray background contamination, noise as well as imperfection of imaging system, it is hard to determine the PSF analytically or measure it experimentally. Therefore, we propose a blind deconvolution method to restore both the spatial distributions of the Kα emission and the system's PSF from the coded images based on the maximum-likelihood scheme. Experimental restoration results from penumbral imaging and ring coded imaging demonstrated that both the structure integrity and the rich detail information can be well preserved.
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8
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Cristoforetti G, Anania MP, Faenov AY, Giulietti A, Giulietti D, Hansen SB, Koester P, Labate L, Levato T, Pikuz TA, Gizzi LA. Spatially resolved analysis of Kα x-ray emission from plasmas induced by a femtosecond weakly relativistic laser pulse at various polarizations. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:023103. [PMID: 23496627 DOI: 10.1103/physreve.87.023103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 11/15/2012] [Indexed: 06/01/2023]
Abstract
Spatially resolved K-shell spectroscopy is used here to investigate the interaction of an ultrashort laser pulse (λ=800 nm, τ=40 fs) with a Ti foil under intense irradiation (Iλ(2)=2×10(18)Wμm(2)cm(-2)) and the following fast electron generation and transport into the target. The effect of laser pulse polarization (p, s, and circular) on the Kα yield and line shape is probed. The radial structure of intensity and width of the lines, obtained by a discretized Abel deconvolution algorithm, suggests an annular distribution of both the hot electron propagation into the target and the target temperature. An accurate modeling of Kα line shapes was performed, revealing temperature gradients, going from a few eV up to 15-20 eV, depending on the pulse polarization. Results are discussed in terms of mechanisms of hot electron generation and of their transport through the preplasma in front of the target.
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Affiliation(s)
- G Cristoforetti
- Intense Laser Irradiation Laboratory (ILIL), INO-CNR, Via G. Moruzzi 1, 56124 Pisa, Italy
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9
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Akli KU, Orban C, Schumacher D, Storm M, Fatenejad M, Lamb D, Freeman RR. Coupling of high-intensity laser light to fast electrons in cone-guided fast ignition. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:065402. [PMID: 23367996 DOI: 10.1103/physreve.86.065402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Indexed: 06/01/2023]
Abstract
Cu wires attached to Al cones are used to investigate the energy coupling efficiency of laser light to fast electrons through a cone into a dense plasma. We present experimental and simulation results demonstrating the effect on the energy coupling of effectively placing the cone in a surrounding high density plasma as well as the effect of a large preformed plasma inside the cone. Thick cone walls, simulating plasma surrounding the cone in fast ignition, reduce the energy coupling by a factor of up to 4. An increase in prepulse inside the cone by a factor of 50 further reduces coupling by a factor of 3. Simulations with the pic code lsp that include the laser plasma interaction and the preformed plasma from the flash code show that electron refluxing in thin cone-wall targets enhances coupling to the wire. The implications for full-scale cone-guided fast ignition are discussed.
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Affiliation(s)
- K U Akli
- The Ohio State University, Columbus, Ohio 43210, USA
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10
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Akli KU, Storm MJ, McMahon M, Jiang S, Ovchinnikov V, Schumacher DW, Freeman RR, Dyer G, Ditmire T. Time dependence of fast electron beam divergence in ultraintense laser-plasma interactions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:026404. [PMID: 23005866 DOI: 10.1103/physreve.86.026404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 06/25/2012] [Indexed: 06/01/2023]
Abstract
We report on the measurement and computer simulation of the divergence of fast electrons generated in an ultraintense laser-plasma interaction (LPI) and the subsequent propagation in a nonrefluxing target. We show that, at Iλ(2) of 10(20) Wcm(-2)μm(2), the time-integrated electron beam full divergence angle is (60±5)°. However, our time-resolved 2D particle-in-cell simulations show the initial beam divergence to be much smaller (≤30°). Our simulations show the divergence to monotonically increase with time, reaching a final value of (68±7)° after the passage of the laser pulse, consistent with the experimental time-integrated measurements. By revealing the time-dependent nature of the LPI, we find that a substantial fraction of the laser energy (~7%) is transported up to 100 μm with a divergence of 32°.
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Affiliation(s)
- K U Akli
- The Ohio State University, Columbus, Ohio 43210, USA
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11
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Stoeckl C, Fiksel G, Guy D, Mileham C, Nilson PM, Sangster TC, Shoup MJ, Theobald W. A spherical crystal imager for OMEGA EP. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:033107. [PMID: 22462906 DOI: 10.1063/1.3693348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A narrowband x ray imager for the Cu K(α) line at ~8 keV using a spherically bent quartz crystal has been implemented on the OMEGA EP laser at the University of Rochester. The quartz crystal is cut along the 2131 (211) planes for a 2d spacing of 0.3082 nm, resulting in a Bragg angle of 88.7°, very close to normal incidence. An optical system is used to remotely align the spherical crystal without breaking the vacuum of the target chamber. The images show a high signal-to-background ratio of typically >100:1 with laser energies ≥1 kJ at a 10-ps pulse duration and a spatial resolution of less than 10 μm.
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Affiliation(s)
- C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
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12
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Li X, Wang J, Zhu W, Ye Y, Li J, Yu Y. Enhanced inner-shell x-ray emission by femtosecond-laser irradiation of solid cone targets. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:046404. [PMID: 21599313 DOI: 10.1103/physreve.83.046404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 12/06/2010] [Indexed: 05/30/2023]
Abstract
The possibility of enhancing inner-shell x-ray emission, especially Kα emission, by femtosecond-laser irradiation of solid cones instead of foils was investigated theoretically. In a model for hot electron (HE) transport and Kα x-ray generation, Kα emission from laser-irradiated solid cones and foils is investigated. As a complementarity to the model, the contributions from electric and magnetic fields generated by the HE current in solid cones and foils are discussed. The results indicate that the efficiency of HE energy conversion to Kα photons is improved and the optimum HE temperature is increased.
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Affiliation(s)
- XiaoYa Li
- National Key Laboratory of Shock Wave and Detonation Physics, Mianyang, 621900 Sichuan, China.
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13
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Lin XX, Li YT, Liu BC, Liu F, Du F, Wang SJ, Lu X, Chen LM, Zhang L, Liu X, Wang J, Liu F, Liu XL, Wang ZH, Ma JL, Wei ZY, Zhang J. Effect of prepulse on fast electron lateral transport at the target surface irradiated by intense femtosecond laser pulses. Phys Rev E 2011; 82:046401. [PMID: 21230399 DOI: 10.1103/physreve.82.046401] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 07/09/2010] [Indexed: 11/07/2022]
Abstract
The effects of preplasma on lateral fast electron transport at front target surface, irradiated by ultraintense (>10(18) W/cm2) laser pulses, are investigated by Kα imaging technique. A large annular Kα halo with a diameter of ∼560 μm surrounding a central spot is observed. A specially designed steplike target is used to identify the possible mechanisms. It is believed that the halos are mainly generated by the lateral diffusion of fast electrons due to the electrostatic and magnetic fields in the preplasma. This is illustrated by simulated electron trajectories using a numerical model.
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Affiliation(s)
- X X Lin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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14
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Zamponi F, Lübcke A, Kämpfer T, Uschmann I, Förster E, Robinson APL, Giulietti A, Köster P, Labate L, Levato T, Gizzi LA. Directional bremsstrahlung from a Ti laser-produced x-ray source at relativistic intensities in the 3-12 keV range. PHYSICAL REVIEW LETTERS 2010; 105:085001. [PMID: 20868103 DOI: 10.1103/physrevlett.105.085001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 05/12/2010] [Indexed: 05/29/2023]
Abstract
Front and rear side x-ray emission from thin titanium foils irradiated by ultraintense laser pulses at intensities up to ≈5 × 10(19) W/cm2 was measured using a high-resolution imaging system. Significant differences in intensity, dimension, and spectrum between front and rear side emission intensity in the 3-12 keV photon energy range was found even for 5 μm thin Ti foils. Simulations and analysis of space-resolved spectra explain this behavior in terms of directional bremsstrahlung emission from fast electrons generated during the interaction process.
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Affiliation(s)
- F Zamponi
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena, Germany.
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15
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Zastrau U, Audebert P, Bernshtam V, Brambrink E, Kämpfer T, Kroupp E, Loetzsch R, Maron Y, Ralchenko Y, Reinholz H, Röpke G, Sengebusch A, Stambulchik E, Uschmann I, Weingarten L, Förster E. Temperature and Kalpha-yield radial distributions in laser-produced solid-density plasmas imaged with ultrahigh-resolution x-ray spectroscopy. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 81:026406. [PMID: 20365664 DOI: 10.1103/physreve.81.026406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Indexed: 05/29/2023]
Abstract
We study warm dense matter formed by subpicosecond laser irradiation at several 10(19) W/cm(2) of thin Ti foils using x-ray spectroscopy with high spectral (E/DeltaE approximately 15,000) and one-dimensional spatial (Deltax=13.5 microm) resolutions. Ti Kalpha doublets modeled by line-shape calculations are compared with Abel-inverted single-pulse experimental spectra and provide radial distributions of the bulk-electron temperature and the absolute-photon number Kalpha yield in the target interiors. A core with approximately 40 eV extends homogeneously up to ten times the laser-focus size. The spatial distributions of the bulk-electron temperature and Kalpha yield are strongly correlated.
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Affiliation(s)
- U Zastrau
- Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany.
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16
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Lu W, Nicoul M, Shymanovich U, Tarasevitch A, Zhou P, Sokolowski-Tinten K, von der Linde D, Masek M, Gibbon P, Teubner U. Optimized Kalpha x-ray flashes from femtosecond-laser-irradiated foils. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:026404. [PMID: 19792265 DOI: 10.1103/physreve.80.026404] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Indexed: 05/28/2023]
Abstract
We investigate the generation of ultrashort Kalpha pulses from plasmas produced by intense femtosecond p-polarized laser pulses on Copper and Titanium targets. Particular attention is given to the interplay between the angle of incidence of the laser beam on the target and a controlled prepulse. It is observed experimentally that the Kalpha yield can be optimized for correspondingly different prepulse and plasma scale-length conditions. For steep electron-density gradients, maximum yields can be achieved at larger angles. For somewhat expanded plasmas expected in the case of laser pulses with a relatively poor contrast, the Kalpha yield can be enhanced by using a near-normal-incidence geometry. For a certain scale-length range (between 0.1 and 1 times a laser wavelength) the optimized yield is scale-length independent. Physically this situation arises because of the strong dependence of collisionless absorption mechanisms-in particular resonance absorption-on the angle of incidence and the plasma scale length, giving scope to optimize absorption and hence the Kalpha yield. This qualitative description is supported by calculations based on the classical resonance absorption mechanism and by particle-in-cell simulations. Finally, the latter simulations also show that even for initially steep gradients, a rapid profile expansion occurs at oblique angles in which ions are pulled back toward the laser by hot electrons circulating at the front of the target. The corresponding enhancement in Kalpha yield under these conditions seen in the present experiment represents strong evidence for this suprathermal shelf formation effect.
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Affiliation(s)
- W Lu
- Institut für Experimentelle Physik, Universität Duisburg-Essen, D-47048 Duisburg, Germany
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17
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Fourmaux S, Serbanescu C, Kincaid RE, Krol A, Kieffer JC. K(alpha) x-ray emission characterization of 100 Hz, 15 mJ femtosecond laser system with high contrast ratio. APPLIED PHYSICS. B, LASERS AND OPTICS 2008; 94:569-575. [PMID: 20052295 PMCID: PMC2801139 DOI: 10.1007/s00340-008-3342-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report K(alpha) x-ray production with a high energy (110 mJ per pulse at 800 nm before compression/15 mJ at 400 nm after compression), high repetition rate (100 Hz), and high pulse contrast (better than 10(-9) at 400 nm) laser system. To develop laser-based x-ray sources for biomedical imaging requires to use high-energy and high-power ultra-fast laser system where compression is achieved under vacuum. Using this type of laser system, we demonstrate long-term stability of the x-ray yield, conversion efficiency higher than 1.5 x 10(-5) with a Mo target, and the x-ray spot size close to the optical focal spot. This high-repetition K(alpha) x-ray source can be very useful for x-ray phase-contrast imaging.
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Affiliation(s)
- S Fourmaux
- INRS-EMT, Université du Québec, Varennes, J3X 1S2, Canada,
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18
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Chen H, Shepherd R, Chung HK, Kemp A, Hansen SB, Wilks SC, Ping Y, Widmann K, Fournier KB, Dyer G, Faenov A, Pikuz T, Beiersdorfer P. Fast-electron-relaxation measurement for laser-solid interaction at relativistic laser intensities. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:056402. [PMID: 18233771 DOI: 10.1103/physreve.76.056402] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 09/25/2007] [Indexed: 05/25/2023]
Abstract
We present measurements of the fast-electron-relaxation time in short-pulse (0.5 ps) laser-solid interactions for laser intensities of 10(17), 10(18), and 10(19) Wcm2, using a picosecond time-resolved x-ray spectrometer and a time-integrated electron spectrometer. We find that the laser coupling to hot electrons increases as the laser intensity becomes relativistic, and that the thermalization of fast electrons occurs over time scales on the order of 10 ps at all laser intensities. The experimental data are analyzed using a combination of models that include Kalpha generation, collisional coupling, and plasma expansion.
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Affiliation(s)
- H Chen
- Physics and Advanced Technologies, Lawrence Livermore National Laboratory, University of California, Livermore, California 94550, USA
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19
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Labate L, Giulietti A, Giulietti D, Köster P, Levato T, Gizzi LA, Zamponi F, Lübcke A, Kämpfer T, Uschmann I, Förster E. Novel x-ray multispectral imaging of ultraintense laser plasmas by a single-photon charge coupled device based pinhole camera. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:103506. [PMID: 17979418 DOI: 10.1063/1.2800774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Spectrally resolved two-dimensional imaging of ultrashort laser-produced plasmas is described, obtained by means of an advanced technique. The technique has been tested with microplasmas produced by ultrashort relativistic laser pulses. The technique is based on the use of a pinhole camera equipped with a charge coupled device detector operating in the single-photon regime. The spectral resolution is about 150 eV in the 4-10 keV range, and images in any selected photon energy range have a spatial resolution of 5 microm. The potential of the technique to study fast electron propagation in ultraintense laser interaction with multilayer targets is discussed and some preliminary results are shown.
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Affiliation(s)
- L Labate
- Intense Laser Irradiation Laboratory, IPCF, Consiglio Nazionale delle Ricerche, Via Moruzzi 1, 56124 Pisa, Italy.
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20
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Riley D, Angulo-Gareta JJ, Khattak FY, Lamb MJ, Foster PS, Divall EJ, Hooker CJ, Langley AJ, Clarke RJ, Neely D. Kalpha yields from Ti foils irradiated with ultrashort laser pulses. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:016406. [PMID: 15697734 DOI: 10.1103/physreve.71.016406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Indexed: 05/24/2023]
Abstract
We have studied the emission of Kalpha radiation from Ti foils irradiated with ultrashort (45 fs) laser pulses. We utilized the fundamental (800 nm) light from a Ti:sapphire laser on bare foils and foils coated with a thin layer of parylene E (CH). The focusing was varied widely to give a range of intensities from approximately 10(15) - 10(19) W cm(-2). Our results show a conversion efficiency of laser to Kalpha energy of approximately 10(-4) at tight focus for both types of targets. In addition, the coated targets exhibited strong secondary peaks of conversion at large defocus, which we believe are due to modification of the extent of preformed plasma due to the dielectric nature of the plastic layer. This in turn affects the level of resonance absorption. A simple model of Kalpha production predicts a much higher conversion than seen experimentally and possible reasons for this are discussed.
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Affiliation(s)
- D Riley
- School of Mathematics and Physics, Queen's University of Belfast, University Road, Belfast, BT7 1NN, Northern Ireland.
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