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Antoine Rousse - One of the best experts on this subject based on the ideXlab platform.
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controlled Betatron x ray radiation from tunable optically injected electrons
Physical Review Letters, 2011Co-Authors: Sébastien Corde, Ta K. Phuoc, R Fitour, Jerome Faure, A Tafzi, J P Goddet, Victor Malka, Antoine RousseAbstract:The features of Betatron x-ray emission produced in a laser-plasma accelerator are closely linked to the properties of the relativistic electrons which are at the origin of the radiation. While in interaction regimes explored previously the source was by nature unstable, following the fluctuations of the electron beam, we demonstrate in this Letter the possibility to generate x-ray Betatron radiation with controlled and reproducible features, allowing fine studies of its properties. To do so, Betatron radiation is produced using monoenergetic electrons with tunable energies from a laser-plasma accelerator with colliding pulse injection [J. Faure et al., Nature (London) 444, 737 (2006)]. The presented study provides evidence of the correlations between electrons and x-rays, and the obtained results open significant perspectives toward the production of a stable and controlled femtosecond Betatron x-ray source in the keV range.
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single shot phase contrast imaging using laser produced Betatron x ray beams
Optics Letters, 2011Co-Authors: S Fourmaux, Ta K. Phuoc, Sébastien Corde, Victor Malka, Philippe Lassonde, G Lebrun, S Payeur, F Martin, Stephane Sebban, Antoine RousseAbstract:Development of x-ray phase contrast imaging applications with a laboratory scale source have been limited by the long exposure time needed to obtain one image. We demonstrate, using the Betatron x-ray radiation produced when electrons are accelerated and wiggled in the laser-wakefield cavity, that a high-quality phase contrast image of a complex object (here, a bee), located in air, can be obtained with a single laser shot. The Betatron x-ray source used in this proof of principle experiment has a source diameter of 1.7 μm and produces a synchrotron spectrum with critical energy Ec=12.3±2.5 keV and 109 photons per shot in the whole spectrum.
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Betatron radiation from density tailored plasmas
Physics of Plasmas, 2008Co-Authors: K. Ta Phuoc, V. Leurent, E. Cormier-michel, C G R Geddes, C.b. Schroeder, E Esarey, Antoine Rousse, Wim LeemansAbstract:In laser wakefield accelerators, electron motion is driven by intense forces that depend on the plasma density. Transverse oscillations in the accelerated electron orbits produce Betatron radiation. The electron motion and the resulting Betatron radiation spectrum can therefore be controlled by shaping the plasma density along the orbit of the electrons. Here, a method based on the use of a plasma with a longitudinal density variation (density depression or step) is proposed to increase the transverse oscillation amplitude and the energy of the electrons accelerated in a wakefield cavity. For fixed laser parameters, by appropriately tailoring the plasma profile, the Betatron radiation emitted by these electrons is significantly increased in both flux and energy.
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Betatron oscillations of electrons accelerated in laser wakefields characterized by spectral x ray analysis
Physical Review E, 2008Co-Authors: F Albert, K. Ta Phuoc, R Fitour, A Tafzi, Rahul Shah, F Burgy, Jeanphilippe Rousseau, D Douillet, T Lefrou, Antoine RousseAbstract:Relativistic electrons accelerated by laser wakefields can produce x-ray beams from their motion in plasma termed Betatron oscillations. Detailed spectral characterization is presented in which the amplitude of the Betatron oscillations $r$ is studied by numerical analysis of electron and x-ray spectra measured simultaneously. We find that $r$ reaches as low as $1\text{ }\ensuremath{\mu}\text{m}$ in agreement with previous studies of radiation based on coherence and far-field spatial profile.
Jie Zhang - One of the best experts on this subject based on the ideXlab platform.
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high resolution phase contrast imaging of biological specimens using a stable Betatron x ray source in the multiple exposure mode
Scientific Reports, 2019Co-Authors: Bo Guo, Jie Zhang, C H Pai, Jianfei Hua, Hsuhsin Chu, Xiaohui Zhang, Chaojie Zhang, W B Mori, C Joshi, Jyhpyng WangAbstract:Phase-contrast imaging using X-ray sources with high spatial coherence is an emerging tool in biology and material science. Much of this research is being done using large synchrotron facilities or relatively low-flux microfocus X-ray tubes. An alternative high-flux, ultra-short and high-spatial-coherence table-top X-ray source based on Betatron motions of electrons in laser wakefield accelerators has the promise to produce high quality images. In previous phase-contrast imaging studies with Betatron sources, single-exposure images with a spatial resolution of 6–70 μm were reported by using large-scale laser systems (60–200 TW). Furthermore, images obtained with multiple exposures tended to have a reduced contrast and resolution due to the shot-to-shot fluctuations. In this article, we demonstrate that a highly stable multiple-exposure Betatron source, with an effective average source size of 5 μm, photon number and pointing jitters of <5% and spectral fluctuation of <10%, can be obtained by utilizing ionization injection in pure nitrogen plasma using a 30–40 TW laser. Using this source, high quality phase-contrast images of biological specimens with a 5-μm resolution are obtained for the first time. This work shows a way for the application of high resolution phase-contrast imaging with stable Betatron sources using modest power, high repetition-rate lasers.
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enhancement of laser driven Betatron x rays by a density depressed plasma structure
Plasma Physics and Controlled Fusion, 2019Co-Authors: Bo Guo, Zhi Cheng, Shuang Liu, Xiao Nan Ning, Jie Zhang, C H Pai, Jianfei Hua, Hsuhsin Chu, Jyhpyng WangAbstract:We report a significant enhancement of Betatron radiation from a laser wakefield accelerator by inserting a density-depressed plasma structure. By using a technique of transverse laser machining, a longitudinally density-depressed plasma structure with tunable length and position has been fabricated to increase the Betatron amplitude of the electron beam in the laser wakefield accelerator, leading to an enhanced photon number and critical energy of the Betatron X-ray beam. By adjusting the length and position of the plasma density depression region, the photon number of the Betatron X-ray is enhanced by a factor of 3, and the critical energy is enhanced by a factor of 1.4.
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resonantly enhanced Betatron hard x rays from ionization injected electrons in a laser plasma accelerator
Scientific Reports, 2016Co-Authors: Kai Huang, Zheng Ming Sheng, Liming Chen, Nasr A M Hafz, J R Zhao, M Z Tao, Mingwei Chen, Mohammad Mirzaie, T Sokollik, Jie ZhangAbstract:Ultrafast Betatron x-ray emission from electron oscillations in laser wakefield acceleration (LWFA) has been widely investigated as a promising source. Betatron x-rays are usually produced via self-injected electron beams, which are not controllable and are not optimized for x-ray yields. Here, we present a new method for bright hard x-ray emission via ionization injection from the K-shell electrons of nitrogen into the accelerating bucket. A total photon yield of 8 × 108/shot and 108 photons with energy greater than 110 keV is obtained. The yield is 10 times higher than that achieved with self-injection mode in helium under similar laser parameters. The simulation suggests that ionization-injected electrons are quickly accelerated to the driving laser region and are subsequently driven into Betatron resonance. The present scheme enables the single-stage Betatron radiation from LWFA to be extended to bright γ-ray radiation, which is beyond the capability of 3rd generation synchrotrons.
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diagnosis of bubble evolution in laser wakefield acceleration via angular distributions of Betatron x rays
Applied Physics Letters, 2014Co-Authors: Liming Chen, Zheng Ming Sheng, J Dunn, Wenchao Yan, Nasr A M Hafz, Kai Huang, Jie ZhangAbstract:We present an indirect method to diagnose the electron beam behaviors and bubble dynamic evolution in a laser-wakefield accelerator. Four kinds of typical bubble dynamic evolution and, hence, electron beam behaviors observed in Particle-In-Cell simulations are identified correspondingly by simultaneous measurement of distinct angular distributions of the Betatron radiation and electron beam energy spectra in experiment. The reconstruction of the bubble evolution may shed light on finding an effective way to better generate high-quality electron beams and enhanced Betatron X-rays.
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concurrence of monoenergetic electron beams and bright x rays from an evolving laser plasma bubble
Proceedings of the National Academy of Sciences of the United States of America, 2014Co-Authors: Wenchao Yan, Zheng Ming Sheng, Liming Chen, J Dunn, Min Chen, L Zhang, Kai Huang, Jie ZhangAbstract:Desktop laser plasma acceleration has proven to be able to generate gigaelectronvolt-level quasi-monoenergetic electron beams. Moreover, such electron beams can oscillate transversely (wiggling motion) in the laser-produced plasma bubble/channel and emit collimated ultrashort X-ray flashes known as Betatron radiation with photon energy ranging from kiloelectronvolts to megaelectronvolts. This implies that usually one cannot obtain bright Betatron X-rays and high-quality electron beams with low emittance and small energy spread simultaneously in the same accelerating wave bucket. Here, we report the first (to our knowledge) experimental observation of two distinct electron bunches in a single laser shot, one featured with quasi-monoenergetic spectrum and another with continuous spectrum along with large emittance. The latter is able to generate high-flux Betatron X-rays. Such is observed only when the laser self-guiding is extended over 4 mm at a fixed plasma density (4 × 1018 cm−3). Numerical simulation reveals that two bunches of electrons are injected at different stages due to the bubble evolution. The first bunch is injected at the beginning to form a stable quasi-monoenergetic electron beam, whereas the second one is injected later due to the oscillation of the bubble size as a result of the change of the laser spot size during the propagation. Due to the inherent temporal synchronization, this unique electron–photon source can be ideal for pump–probe applications with femtosecond time resolution.
Victor Malka - One of the best experts on this subject based on the ideXlab platform.
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High-Brilliance Betatron γ-Ray Source Powered by Laser-Accelerated Electrons
Physical Review Letters, 2018Co-Authors: J. Ferri, K. Ta Phuoc, Sébastien Corde, A. Döpp, Agustin Lifschitz, A. Doche, C. Thaury, B. Mahieu, I. Andriyash, Victor MalkaAbstract:Recent progress in laser-driven plasma acceleration now enables the acceleration of electrons to several gigaelectronvolts. Taking advantage of these novel accelerators, ultrashort, compact, and spatially coherent x-ray sources called Betatron radiation have been developed and applied to high-resolution imaging. However, the scope of the Betatron sources is limited by a low energy efficiency and a photon energy in the 10 s of kiloelectronvolt range, which for example prohibits the use of these sources for probing dense matter. Here, based on three-dimensional particle-in-cell simulations, we propose an original hybrid scheme that combines a low-density laser-driven plasma accelerator with a high-density beam-driven plasma radiator, thereby considerably increasing the photon energy and the radiated energy of the Betatron source. The energy efficiency is also greatly improved, with about 1% of the laser energy transferred to the radiation, and the gamma-ray photon energy exceeds the megaelectronvolt range when using a 15 J laser pulse. This high-brilliance hybrid Betatron source opens the way to a wide range of applications requiring MeV photons, such as the production of medical isotopes with photonuclear reactions, radiography of dense objects in the defense or industrial domains, and imaging in nuclear physics.
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controlled Betatron x ray radiation from tunable optically injected electrons
Physical Review Letters, 2011Co-Authors: Sébastien Corde, Ta K. Phuoc, R Fitour, Jerome Faure, A Tafzi, J P Goddet, Victor Malka, Antoine RousseAbstract:The features of Betatron x-ray emission produced in a laser-plasma accelerator are closely linked to the properties of the relativistic electrons which are at the origin of the radiation. While in interaction regimes explored previously the source was by nature unstable, following the fluctuations of the electron beam, we demonstrate in this Letter the possibility to generate x-ray Betatron radiation with controlled and reproducible features, allowing fine studies of its properties. To do so, Betatron radiation is produced using monoenergetic electrons with tunable energies from a laser-plasma accelerator with colliding pulse injection [J. Faure et al., Nature (London) 444, 737 (2006)]. The presented study provides evidence of the correlations between electrons and x-rays, and the obtained results open significant perspectives toward the production of a stable and controlled femtosecond Betatron x-ray source in the keV range.
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single shot phase contrast imaging using laser produced Betatron x ray beams
Optics Letters, 2011Co-Authors: S Fourmaux, Ta K. Phuoc, Sébastien Corde, Victor Malka, Philippe Lassonde, G Lebrun, S Payeur, F Martin, Stephane Sebban, Antoine RousseAbstract:Development of x-ray phase contrast imaging applications with a laboratory scale source have been limited by the long exposure time needed to obtain one image. We demonstrate, using the Betatron x-ray radiation produced when electrons are accelerated and wiggled in the laser-wakefield cavity, that a high-quality phase contrast image of a complex object (here, a bee), located in air, can be obtained with a single laser shot. The Betatron x-ray source used in this proof of principle experiment has a source diameter of 1.7 μm and produces a synchrotron spectrum with critical energy Ec=12.3±2.5 keV and 109 photons per shot in the whole spectrum.
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direct observation of Betatron oscillations in a laser plasma electron accelerator
EPL, 2008Co-Authors: Yannick Glinec, Jerome Faure, Agustin Lifschitz, J Vieira, Ricardo Fonseca, L O Silva, Victor MalkaAbstract:During experiments performed on a laser-plasma–based accelerator, correlation of the electron output angle with the electron energy has been observed. These spectral oscillations of the electron beam centroid are attributed to Betatron oscillations of the electron beam during its propagation. An analytical model for Betatron oscillations including constant longitudinal acceleration is described and used to validate the scenario and retrieve physical parameters. The oscillations can arise from an off-axis injection of the electrons, which can be reproduced using an asymmetric laser intensity profile in Particle-In-Cell (PIC) simulations. This study emphasizes the influence of non-ideal interaction conditions inherent to experiments.
E Esarey - One of the best experts on this subject based on the ideXlab platform.
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modeling classical and quantum radiation from laser plasma accelerators
Physical Review Special Topics-accelerators and Beams, 2013Co-Authors: C G R Geddes, C.b. Schroeder, E Esarey, G R Plateau, Min Chen, S S Bulanov, S G Rykovanov, W P LeemansAbstract:The development of models and the ``Virtual Detector for Synchrotron Radiation'' (vdsr) code that accurately describe the production of synchrotron radiation are described. These models and code are valid in the classical and linear (single-scattering) quantum regimes and are capable of describing radiation produced from laser-plasma accelerators (LPAs) through a variety of mechanisms including Betatron radiation, undulator radiation, and Thomson/Compton scattering. Previous models of classical synchrotron radiation, such as those typically used for undulator radiation, are inadequate in describing the radiation spectra from electrons undergoing small numbers of oscillations. This is due to an improper treatment of a mathematical evaluation at the end points of an integration that leads to an unphysical plateau in the radiation spectrum at high frequencies, the magnitude of which increases as the number of oscillation periods decreases. This is important for Betatron radiation from LPAs, in which the Betatron strength parameter is large but the number of Betatron periods is small. The code vdsr allows the radiation to be calculated in this regime by full integration over each electron trajectory, including end-point effects, and this code is used to calculate Betatron radiation for cases of experimental interest. Radiation from Thomson scattering and Compton scattering is also studied with vdsr. For Thomson scattering, radiation reaction is included by using the Sokolov method for the calculation of the electron dynamics. For Compton scattering, quantum recoil effects are considered in vdsr by using Monte Carlo methods. The quantum calculation has been benchmarked with the classical calculation in a classical regime.
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low emittance electron bunches from a laser plasma accelerator measured using single shot x ray spectroscopy
Physical Review Letters, 2012Co-Authors: G R Plateau, C G R Geddes, E Esarey, D B Thorn, N H Matlis, Min Chen, C Benedetti, A J Gonsalves, K Nakamura, C.b. SchroederAbstract:: X-ray spectroscopy is used to obtain single-shot information on electron beam emittance in a low-energy-spread 0.5 GeV-class laser-plasma accelerator. Measurements of Betatron radiation from 2 to 20 keV used a CCD and single-photon counting techniques. By matching x-ray spectra to Betatron radiation models, the electron bunch radius inside the plasma is estimated to be ~0.1 μm. Combining this with simultaneous electron spectra, normalized transverse emittance is estimated to be as low as 0.1 mm mrad, consistent with three-dimensional particle-in-cell simulations. Correlations of the bunch radius with electron beam parameters are presented.
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low emittance electron bunches from a laser plasma accelerator measured using single shot x ray spectroscopy
Physical Review Letters, 2012Co-Authors: G R Plateau, C G R Geddes, E Esarey, D B Thorn, N H Matlis, Min Chen, C Benedetti, A J Gonsalves, K Nakamura, C.b. SchroederAbstract:X-ray spectroscopy is used to obtain single-shot information on electron beam emittance in a low-energy-spread 0.5 GeV-class laser-plasma accelerator. Measurements of Betatron radiation from 2 to 20 keV used a CCD and single-photon counting techniques. By matching x-ray spectra to Betatron radiation models, the electron bunch radius inside the plasma is estimated to be $\ensuremath{\sim}0.1\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. Combining this with simultaneous electron spectra, normalized transverse emittance is estimated to be as low as 0.1 mm mrad, consistent with three-dimensional particle-in-cell simulations. Correlations of the bunch radius with electron beam parameters are presented.
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spectroscopy of Betatron radiation emitted from laser produced wakefield accelerated electrons
Review of Scientific Instruments, 2010Co-Authors: D B Thorn, C G R Geddes, C.b. Schroeder, E Esarey, N H Matlis, G R Plateau, M Battaglia, S Shiraishi, Th Stohlker, Csaba TothAbstract:X-ray Betatron radiation is produced by oscillations of electrons in the intense focusing field of a laser-plasma accelerator. These hard x-rays show promise for use in femtosecond-scale time-resolved radiography of ultrafast processes. However, the spectral characteristics of Betatron radiation have only been inferred from filter pack measurements. In order to achieve higher resolution spectral information about the Betatron emission, we used an x-ray charge-coupled device to record the spectrum of Betatron radiation, with a full width at half maximum resolution of 225 eV. In addition, we have recorded simultaneous electron and x-ray spectra along with x-ray images that allow for a determination of the Betatron emission source size, as well as differences in the x-ray spectra as a function of the energy spectrum of accelerated electrons.
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Betatron radiation from density tailored plasmas
Physics of Plasmas, 2008Co-Authors: K. Ta Phuoc, V. Leurent, E. Cormier-michel, C G R Geddes, C.b. Schroeder, E Esarey, Antoine Rousse, Wim LeemansAbstract:In laser wakefield accelerators, electron motion is driven by intense forces that depend on the plasma density. Transverse oscillations in the accelerated electron orbits produce Betatron radiation. The electron motion and the resulting Betatron radiation spectrum can therefore be controlled by shaping the plasma density along the orbit of the electrons. Here, a method based on the use of a plasma with a longitudinal density variation (density depression or step) is proposed to increase the transverse oscillation amplitude and the energy of the electrons accelerated in a wakefield cavity. For fixed laser parameters, by appropriately tailoring the plasma profile, the Betatron radiation emitted by these electrons is significantly increased in both flux and energy.
Sébastien Corde - One of the best experts on this subject based on the ideXlab platform.
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High-Brilliance Betatron γ-Ray Source Powered by Laser-Accelerated Electrons
Physical Review Letters, 2018Co-Authors: J. Ferri, K. Ta Phuoc, Sébastien Corde, A. Döpp, Agustin Lifschitz, A. Doche, C. Thaury, B. Mahieu, I. Andriyash, Victor MalkaAbstract:Recent progress in laser-driven plasma acceleration now enables the acceleration of electrons to several gigaelectronvolts. Taking advantage of these novel accelerators, ultrashort, compact, and spatially coherent x-ray sources called Betatron radiation have been developed and applied to high-resolution imaging. However, the scope of the Betatron sources is limited by a low energy efficiency and a photon energy in the 10 s of kiloelectronvolt range, which for example prohibits the use of these sources for probing dense matter. Here, based on three-dimensional particle-in-cell simulations, we propose an original hybrid scheme that combines a low-density laser-driven plasma accelerator with a high-density beam-driven plasma radiator, thereby considerably increasing the photon energy and the radiated energy of the Betatron source. The energy efficiency is also greatly improved, with about 1% of the laser energy transferred to the radiation, and the gamma-ray photon energy exceeds the megaelectronvolt range when using a 15 J laser pulse. This high-brilliance hybrid Betatron source opens the way to a wide range of applications requiring MeV photons, such as the production of medical isotopes with photonuclear reactions, radiography of dense objects in the defense or industrial domains, and imaging in nuclear physics.
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Betatron emission as a diagnostic for injection and acceleration mechanisms in laser plasma accelerators
Plasma Physics and Controlled Fusion, 2012Co-Authors: Sébastien Corde, Cédric ThauryAbstract:Betatron x-ray emission in laser-plasma accelerators is a promising compact source that may be an alternative to conventional x-ray sources, based on large scale machines. In addition to its potential as a source, precise measurements of Betatron emission can reveal crucial information about relativistic laser-plasma interaction. We show that the emission length and the position of the x-ray emission can be obtained by placing an aperture mask close to the source, and by measuring the beam profile of the Betatron x-ray radiation far from the aperture mask. The position of the x-ray emission gives information on plasma wave breaking and hence on the laser non-linear propagation. Moreover, the measurement of the longitudinal extension helps one to determine whether the acceleration is limited by pump depletion or dephasing effects. In the case of multiple injections, it is used to retrieve unambiguously the position in the plasma of each injection. This technique is also used to study how, in a capillary discharge, the variations of the delay between the discharge and the laser pulse affect the interaction. The study reveals that, for a delay appropriate for laser guiding, the x-ray emission only occurs in the second half of the capillary: no electrons are injected and accelerated in the first half.
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controlled Betatron x ray radiation from tunable optically injected electrons
Physical Review Letters, 2011Co-Authors: Sébastien Corde, Ta K. Phuoc, R Fitour, Jerome Faure, A Tafzi, J P Goddet, Victor Malka, Antoine RousseAbstract:The features of Betatron x-ray emission produced in a laser-plasma accelerator are closely linked to the properties of the relativistic electrons which are at the origin of the radiation. While in interaction regimes explored previously the source was by nature unstable, following the fluctuations of the electron beam, we demonstrate in this Letter the possibility to generate x-ray Betatron radiation with controlled and reproducible features, allowing fine studies of its properties. To do so, Betatron radiation is produced using monoenergetic electrons with tunable energies from a laser-plasma accelerator with colliding pulse injection [J. Faure et al., Nature (London) 444, 737 (2006)]. The presented study provides evidence of the correlations between electrons and x-rays, and the obtained results open significant perspectives toward the production of a stable and controlled femtosecond Betatron x-ray source in the keV range.
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single shot phase contrast imaging using laser produced Betatron x ray beams
Optics Letters, 2011Co-Authors: S Fourmaux, Ta K. Phuoc, Sébastien Corde, Victor Malka, Philippe Lassonde, G Lebrun, S Payeur, F Martin, Stephane Sebban, Antoine RousseAbstract:Development of x-ray phase contrast imaging applications with a laboratory scale source have been limited by the long exposure time needed to obtain one image. We demonstrate, using the Betatron x-ray radiation produced when electrons are accelerated and wiggled in the laser-wakefield cavity, that a high-quality phase contrast image of a complex object (here, a bee), located in air, can be obtained with a single laser shot. The Betatron x-ray source used in this proof of principle experiment has a source diameter of 1.7 μm and produces a synchrotron spectrum with critical energy Ec=12.3±2.5 keV and 109 photons per shot in the whole spectrum.