Showing papers by "Dino A. Jaroszynski published in 2014"
Rutherford Appleton Laboratory1, University of Strathclyde2, CERN3, Max Planck Society4, Instituto Superior Técnico5, ISCTE – University Institute of Lisbon6, University College London7, Los Alamos National Laboratory8, Imperial College London9, Novosibirsk State University10, Budker Institute of Nuclear Physics11, Daresbury Laboratory12, Ludwig Maximilian University of Munich13, University of Oxford14, University of Düsseldorf15, University of Manchester16
TL;DR: In this article, the authors review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator and demonstrate the power of proton driven wakefield acceleration.
Abstract: New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN—the AWAKE experiment—has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.
104 citations
TL;DR: In this article, the number of photons measured is up to 9'×'106 per shot for a 100 period undulator, with a mean peak brilliance of 1'× '1018 photons/s/mrad2/mm2/0.1% bandwidth.
Abstract: Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 106 per shot for a 100 period undulator, with a mean peak brilliance of 1 × 1018 photons/s/mrad2/mm2/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs.
48 citations
TL;DR: It is demonstrated that EBT2 Gafchromic film is a reliable dosimeter that can be used for dosimetry of VHEE and induced activity due to radionuclide production is found to have a negligible effect on total dose deposition and film response.
Abstract: Very high energy electrons (VHEE) in the range from 100-250 MeV have the potential of becoming an alternative modality in radiotherapy because of their improved dosimetry properties compared with MV photons from contemporary medical linear accelerators. Due to the need for accurate dosimetry of small field size VHEE beams we have performed dose measurements using EBT2 Gafchromic® film. Calibration of the film has been carried out for beams of two different energy ranges: 20 MeV and 165 MeV from conventional radio frequency linear accelerators. In addition, EBT2 film has been used for dose measurements with 135 MeV electron beams produced by a laser-plasma wakefield accelerator. The dose response measurements and percentage depth dose profiles have been compared with calculations carried out using the general-purpose FLUKA Monte Carlo (MC) radiation transport code. The impact of induced radioactivity on film response for VHEEs has been evaluated using the MC simulations. A neutron yield of the order of 10(-5) neutrons cm(-2) per incident electron has been estimated and induced activity due to radionuclide production is found to have a negligible effect on total dose deposition and film response. Neutron and proton contribution to the equivalent doses are negligible for VHEE. The study demonstrates that EBT2 Gafchromic film is a reliable dosimeter that can be used for dosimetry of VHEE. The results indicate an energy-independent response of the dosimeter for 20 MeV and 165 MeV electron beams and has been found to be suitable for dosimetry of VHEE.
38 citations
TL;DR: This paper presents the implementation of refraction in a model that is based on time of flight calculations and the Huygens-Fresnel principle, which allow reproducing the formation of phase contrast images in partially and fully coherent experimental conditions.
Abstract: Interest in phase contrast imaging methods based on electromagnetic wave coherence has increased significantly recently, particularly at X-ray energies. This is giving rise to a demand for effective simulation methods. Coherent imaging approaches are usually based on wave optics, which require significant computational resources, particularly for producing 2D images. Monte Carlo (MC) methods, used to track individual particles/photons for particle physics, are not considered appropriate for describing coherence effects. Previous preliminary work has evaluated the possibility of incorporating coherence in Monte Carlo codes. However, in this paper, we present the implementation of refraction in a model that is based on time of flight calculations and the Huygens-Fresnel principle, which allow reproducing the formation of phase contrast images in partially and fully coherent experimental conditions. The model is implemented in the FLUKA Monte Carlo code and X-ray phase contrast imaging simulations are compared with experiments and wave optics calculations.
29 citations
TL;DR: In this article, the development of such hybrid systems and their potential as future plasma-based accelerators and compact yet high performance light sources is discussed, as well as their application in future laser-driven underdense photocathodes.
Abstract: Spiking electron beam driven plasma waves with novel laser-driven underdense photocathodes can produce electron witness bunches with extreme brightness. The development of such hybrid systems and their potential as future plasma-based accelerators and compact yet high performance light sources is discussed.
22 citations
TL;DR: In this article, the transverse emittance of 120-200 MeV laser wakefield electron bunches after propagation through a triplet of permanent quadrupole magnets was investigated.
Abstract: Electron beams from laser-plasma wakefield accelerators have low transverse emittance, comparable to those from conventional radio frequency accelerators, which highlights their potential for applications, many of which will require the use of quadrupole magnets for optimal electron beam transport. We report on characterizing electron bunches where double bunches are observed under certain conditions. In particular, we present pepper-pot measurements of the transverse emittance of 120–200 MeV laser wakefield electron bunches after propagation through a triplet of permanent quadrupole magnets. It is shown that the normalized emittance at source can be as low as 1 π mm mrad (resolution limited), growing by about five times after propagation through the quadrupoles due to beam energy spread. The inherent energy-dependence of the magnets also enables detection of double electron bunches that could otherwise remain unresolved, providing insight into the self-injection of multiple bunches. The combination of quadrupoles and pepper-pot, in addition, acts as a diagnostic for the alignment of the magnetic triplet.
19 citations
TL;DR: In this paper, the dependence of the resonance between oscillations and emitted field on the betatron amplitude is considered and the ICL model with this essential addition is described using the well-known formalism for the FEL.
Abstract: The ion-channel laser (ICL) is an ultra-compact version of the free-electron laser (FEL), with the undulator replaced by an ion channel. Previous studies of the ICL assumed transverse momentum amplitudes which were unrealistically small for experiments. Here we show that this restriction can be removed by correctly taking into account the dependence of the resonance between oscillations and emitted field on the betatron amplitude, which must be treated as variable. The ICL model with this essential addition is described using the well-known formalism for the FEL. Analysis of the resulting scaled equations shows a realistic prospect of building a compact ICL source for fundamental wavelengths down to UV, and harmonics potentially extending to x-rays. The gain parameter ρ can attain values as high as 0.03, which permits driving an ICL with electron bunches with realistic emittance.
18 citations
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TL;DR: In this article, synchronized, independently tunable and focused μJ-class laser pulses are used to release multiple electron populations via photo-ionization inside an electron-beam driven plasma wave.
Abstract: Synchronized, independently tunable and focused μJ-class laser pulses are used to release multiple electron populations via photo-ionization inside an electron-beam driven plasma wave. By varying the laser foci in the laboratory frame and the position of the underdense photocathodes in the co-moving frame, the delays between the produced bunches and their energies are adjusted. The resulting multibunches have ultra-high quality and brightness, allowing for hitherto impossible bunch configurations such as spatially overlapping bunch populations with strictly separated energies, which opens up a new regime for light sources such as free-electron-lasers.
8 citations
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TL;DR: Knetsch et al. as discussed by the authors showed that the requirements for high quality electron bunch generation and trapping from an underdense photocathode in plasma wakefield accelerators can be substantially relaxed through localizing it on a plasma density downramp.
Abstract: Author(s): Knetsch, Alexander; Karger, Oliver; Wittig, Georg; Groth, Henning; Xi, Yunfeng; Deng, Aihua; Rosenzweig, James Benjamin; Bruhwiler, David Leslie; Smith, Johnathan; Jaroszynski, Dino Anthony; Sheng, Zheng-Ming; Manahan, Grace Gloria; Xia, Guoxing; Jamison, Steven; Hidding, Bernhard | Abstract: It is shown that the requirements for high quality electron bunch generation and trapping from an underdense photocathode in plasma wakefield accelerators can be substantially relaxed through localizing it on a plasma density downramp. This depresses the phase velocity of the accelerating electric field until the generated electrons are in phase, allowing for trapping in shallow trapping potentials. As a consequence the underdense photocathode technique is applicable by a much larger number of accelerator facilities. Furthermore, dark current generation is effectively suppressed.
4 citations
03 Dec 2014
TL;DR: In this article, the authors studied the terahertz wave transmission through plasma and showed that some parts of THz frequency components have been cut off by plasma, and with the density of plasma rising, the starting frequency of the THz prohibited by plasma is going higher.
Abstract: Research on terahertz wave transmission through plasma is significant for researches on plasma itself and transmission discipline of terahertz wave through plasma. It is possible for plasma with suitable density to be an available stealth outerwear for plane or missile in THz waveband. In this paper, plasma is gotten by ionizing inert gases such as argon and helium gases with pulsed high alternating voltage. With electro-optic pump-probe measurement, THz transmission phenomena through plasma have been studied. The experiments show that some parts of THz frequency components have been cut off by plasma, and with the density of plasma rising, the starting frequency of THz prohibited by plasma is going higher. Experiments also provide an assistant scheme for plasma diagnose with terahertz technique.
2 citations
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TL;DR: In this paper, the Landau-Lifshiftz description of radiation reac-tion is adapted into a semi-classical model, for which the Vlasov equation is intractable.
Abstract: Centre de Physique Theorique, Ecole Polytechnique, 91120, Palaiseau, France(Dated: October 8, 2014)We present a novel technique for studying the evolution of a particle distribution using singleparticle dynamics such that the distribution can be accurately reconstructed using fewer particlesthan existing approaches. To demonstrate this, the Landau{Lifshiftz description of radiation reac-tion is adapted into a semi-classical model, for which the Vlasov equation is intractable. Collisionbetween an energetic electron bunch and high-intensity laser pulses are then compared using thetwo theories. Reduction in beam cooling is observed for the semi-classical case.
17 Dec 2014
TL;DR: In this article, the authors treat the radiation reaction as a small perturbation to the applied Lorentz force, and use the Landau-Lifshitz approach to solve the problem.
Abstract: • The Lorentz force describes the motion of a charged particle in an external electromagnetic field, but as the particle accelerates it radiates energy and momentum. • Radiation reaction describes the effect of this radiative loss on the motion of the particle itself. This radiation reaction force is typically extremely small compared to the applied force, so can be safely neglected. • However... as the field becomes strong, the particle radiates more and more, and this correction can become significant: for example, at future high-intensity laser facilities such as ELI. • Furthermore, in strong fields the quantum nature of photon emission may also become important. • Lorentz–Abraham–Dirac equation Fully relativistic equation of motion for a classical point particle [1] ẍ = − q m F b ẋ b + τ∆b ... x b , (1) where τ = q/6πm ' 6× 10−24s is the characteristic time of the electron and ∆b = δ b + ẋẋb. . Jerk term leads to pathological solutions: → Runaway solutions (unphysical) or preaccelerations (violation of causality). . Overcome using the Landau–Lifshitz approach [2]: treat the radiation reaction as a small perturbation to the applied Lorentz force.
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TL;DR: In this article, the authors review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator and demonstrate the power of proton driven wakefield acceleration.
Abstract: New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.
08 Jun 2014
TL;DR: In this paper, the role played by self-focusing of a femtosecond laser in the entrance plume of a gas-filled capillary discharge waveguide is investigated for laser-plasma wakefield acceleration of electrons.
Abstract: The role played by self-focusing of a high-intensity femtosecond laser in the entrance plume of a gas-filled capillary discharge waveguide is investigated for laser-plasma wakefield acceleration of electrons.