| 1. |
- Andreev, N. E., et al.
(författare)
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Analysis of laser wakefield dynamics in capillary tubes
- 2010
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- A general approach to the modifications of the spectrum of a laser pulse interacting with matter is elaborated and used for spectral diagnostics of laser wakefield generation in guiding structures. Analytical predictions of the laser frequency red shift due to the wakefield excited in a capillary waveguide are confirmed by self-consistent modeling results. The role of ionization blue shift, and nonlinear laser pulse and wakefield dynamics on the spectrum modification, is analyzed for recent experiments on plasma wave excitation by an intense laser pulse guided in hydrogen-filled glass capillary tubes up to 8 cm long. The dependence of the spectral frequency shift, measured as a function of filling pressure, capillary tube length and incident laser energy, is in excellent agreement with the simulation results, and the associated longitudinal accelerating field is in the range 1-10 GV m(-1).
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| 2. |
- Assmann, R. W., et al.
(författare)
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EuPRAXIA Conceptual Design Report
- 2020
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Ingår i: European Physical Journal: Special Topics. - : Springer Science and Business Media LLC. - 1951-6355 .- 1951-6401. ; 229:24, s. 3675-4284
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Tidskriftsartikel (refereegranskat)abstract
- This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facility within 8—10 years. © 2020, The Author(s).
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| 3. |
- Aurand, Bastian, et al.
(författare)
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A setup for studies of laser-driven proton acceleration at the Lund Laser Centre
- 2015
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Ingår i: Laser and Particle Beams. - 0263-0346. ; 33:1, s. 59-64
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Tidskriftsartikel (refereegranskat)abstract
- We report on a setup for the investigation of proton acceleration in the regime of target normal sheath acceleration. The main interest here is to focus on stable laser beam parameters as well as a reliable target setup and diagnostics in order to do extensive and systematic studies on the acceleration mechanism. A motorized target alignment system in combination with large target mounts allows for up to 340 shots with high repetition rate without breaking the vacuum. This performance is used to conduct experiments with a split mirror setup exploring the effect of spatial and temporal separation between the pulses on the acceleration mechanism and on the resulting proton beam.
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| 4. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 620:1, s. 76-82
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Konferensbidrag (refereegranskat)abstract
- Low-intensity laser prepulse ( < 10(13) W/cm(2), ns duration) are a major issue in experiments on laser-generation of protons, often limiting the performances of proton sources produced by high-intensity lasers (approximate to 10(19) W/cm(2), ps or fs duration) Several effects are associated to the prepulse and are discussed in this contribution: i) Destruction of thin foil targets by the shock generated by the laser prepulse ii) Creation of preplasma on target front side affecting laser absorption iii) Deformation of target rear side iv) Whole displacement of thin foil targets affecting focusing condition In particular, we show that under oblique high-intensity irradiation and for low prepulse intensities, the proton beam is directed away from the target normal. Deviation is towards the laser forward direction, with an angle that increases with the level and duration of the ASE pedestal. Also, for a given laser pulse, beam deviation increases with proton energy. The observations are discussed in terms of Target Normal Sheath Acceleration, in combination with a laser-controllable shock wave locally deforming the target surface. (C) 2010 Elsevier B.V. All rights reserved.
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| 5. |
- Batani, D., et al.
(författare)
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Effects of laser prepulse on proton generation
- 2010
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Ingår i: Radiation Effects and Defects in Solids. - : Informa UK Limited. - 1042-0150 .- 1029-4953. ; 165:6-10, s. 794-802
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Konferensbidrag (refereegranskat)abstract
- Prepulse is a major issue for laser generation of protons, often limiting the performances of laser sources. Here, we show the use of prepulse (1013W/cm2, ns duration) to actively manipulate the proton beam direction. Under oblique high-intensity irradiation (approximate to 1019W/cm2, ps duration) of the thin foil target, and for low prepulse intensities, the proton beam is directed away from the ounperturbedo target normal. Observations are discussed in terms of target normal sheath acceleration, in combination with a laser-controllable shock locally deforming the target surface.
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| 6. |
- Björklund Svensson, Jonas, et al.
(författare)
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Double-bunches for two-color soft X-ray free-electron laser at the MAX IV Laboratory
- 2018
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Ingår i: Proceedings of FEL2017, Santa Fe, NM, USA. - 9783954501793 ; , s. 269-272
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The ability to generate two-color free-electron laser (FEL) radiation enables a wider range of user experiments than just single-color FEL radiation. There are different schemes for generating the two colors, the original being to use a single bunch and two sets of undulators with different K-parameters. An alternative scheme was recently shown, where two separate bunches in the same RF bucket are used for lasing at different wavelengths in a single set of undulators. We here investigate the feasibility of accelerating and compressing a double-bunch time structure generated in the photocathode electron gun for subsequent use in a soft X-ray FEL at the MAX IV Laboratory.
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| 7. |
- Björklund Svensson, Jonas, et al.
(författare)
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Driver-witness-bunches for plasma-wakefield acceleration at the MAX IV Linear Accelerator
- 2017
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Ingår i: IPAC 2017 - Proceedings of the 8th International Particle Accelerator Conference. - 9783954501823 ; , s. 1743-1746
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Beam-driven plasma-wakefield acceleration is an acceleration scheme promising accelerating fields of at least two to three orders of magnitude higher than in conventional radiofrequency accelerating structures. The scheme relies on using a charged particle bunch (driver) to drive a non-linear plasma wake, into which a second bunch (witness) can be injected at an appropriate distance behind the first, yielding a substantial energy gain of the witness bunch particles. This puts very special demands on the machine providing the particle beam. In this article, we use simulations to show that, if driver-witness-bunches can be generated in the photocathode electron gun, the MAX IV Linear Accelerator could be used for plasma-wakefield acceleration.
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| 8. |
- Björklund Svensson, Jonas, et al.
(författare)
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Low-divergence femtosecond X-ray pulses from a passive plasma lens
- 2021
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Ingår i: Nature Physics. - : Springer Science and Business Media LLC. - 1745-2481 .- 1745-2473. ; 17:5, s. 639-645
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Tidskriftsartikel (refereegranskat)abstract
- Electron and X-ray beams originating from compact laser-wakefield accelerators have very small source sizes that are typically on the micrometre scale. Therefore, the beam divergences are relatively high, which makes it difficult to preserve their high quality during transport to applications. To improve on this, tremendous efforts have been invested in controlling the divergence of the electron beams, but no mechanism for generating collimated X-ray beams has yet been demonstrated experimentally. Here we propose and realize a scheme where electron bunches undergoing focusing in a dense, passive plasma lens can emit X-ray pulses with divergences approaching the incoherent limit. Compared with conventional betatron emission, the divergence of this so-called plasma lens radiation is reduced by more than an order of magnitude in solid angle, while maintaining a similar number of emitted photons per electron. This X-ray source offers the possibility of producing brilliant and collimated few-femtosecond X-ray pulses for ultra-fast science, in particular for studies based on X-ray diffraction and absorption spectroscopy. X-ray pulses with low divergences are produced in a laser-wakefield accelerator by focusing electron bunches in a dense passive plasma lens.
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| 9. |
- Björklund Svensson, Jonas, et al.
(författare)
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Third-order double-achromat bunch compressors for broadband beams
- 2019
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Ingår i: Physical Review Accelerators and Beams. - 2469-9888. ; 22:10
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Tidskriftsartikel (refereegranskat)abstract
- Many state-of-the-art applications for linear accelerators, such as free-electron lasers (FELs) and plasma-wakefield accelerators (PWFAs), require small normalized emittances, and PWFAs in particular are very sensitive to transverse slice offsets along the beam. Dispersive systems, such as bunch compressors, can cause different chromatic aberrations, one of which yields transverse slice offsets. In this paper, we show a design approach to double-achromat bunch compressors which greatly reduces different chromatic aberrations and mitigates coherent synchrotron radiation effects.
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| 10. |
- Burza, Matthias, et al.
(författare)
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Laser wakefield acceleration using wire produced double density ramps
- 2013
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Ingår i: Physical Review Special Topics. Accelerators and Beams. - 1098-4402. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach to implement and control electron injection into the accelerating phase of a laser wakefield accelerator is presented. It utilizes a wire, which is introduced into the flow of a supersonic gas jet creating shock waves and three regions of differing plasma electron density. If tailored appropriately, the laser plasma interaction takes place in three stages: Laser self-compression, electron injection, and acceleration in the second plasma wave period. Compared to self-injection by wave breaking of a nonlinear plasma wave in a constant density plasma, this scheme increases beam charge by up to 1 order of magnitude in the quasimonoenergetic regime. Electron acceleration in the second plasma wave period reduces electron beam divergence by approximate to 25%, and the localized injection at the density downramps results in spectra with less than a few percent relative spread. DOI: 10.1103/PhysRevSTAB.16.011301
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