Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration

Hafz, N.; Gh, Kim; C, Kim; Is, Ko; H, Suk

doi:10.1103/physreve.73.016405

Cited by 24 publications

(17 citation statements)

References 18 publications

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“…For example, both of the Raman forward scattering (RFS) and the Raman backward scattering (RBS) were used to measure the plasma density in underdense plasmas. [1][2][3] It was also shown by particle-in-cell (PIC) simulations that the temperature and density of a homogeneous plasma are simultaneously detectable by measuring RBS and RFS together. 4 Meanwhile, one recent experimental result has shown that the spatial information of a plasma density is extractable using the Raman backward amplification technique based on stimulated Raman scattering.…”

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confidence: 99%

Measuring the magnetic field of a magnetized plasma using Raman scattering

Cho

Kim

Hur

2014

Applied Physics Letters

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We studied the Raman scattering in a magnetized plasma by one-dimensional particle-in-cell (PIC) simulations in non-relativistic regime. It is found from the X-mode dispersion relation that the frequency of the backward scattered wave is downshifted by an amount of upper hybrid frequency, while that of the forward scattered wave merely depends on the magnetic field. We propose such a spectral difference be used to measure simultaneously the plasma density and magnetic field of magnetized plasmas. The idea was verified by a series of PIC simulations, where we used the directional field splitting method to obtain accurate peak position of the scattered waves' frequencies. We compared the frequency shift and the growth rate of the scattering from theory and simulations to obtain reasonably good agreement between them for different external magnetic fields.

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confidence: 99%

Measuring the magnetic field of a magnetized plasma using Raman scattering

Cho

Kim

Hur

2014

Applied Physics Letters

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“…Another fundamental constraint is that, unlike the linacs, the present laser wakefield accelerators do not reliably produce monoenergetic beams (although recent work indicates that this will change in the near future). [47][48][49][50][51][52][53][54][55][56][57] The TUHFF LWA has an electron spectrum that is Maxwellian, with the median energy corresponding to that of the electron plasma in the jet. The energy spread is more than 100% realtive to the mean.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast pulse radiolysis using a terawatt laser wakefield accelerator

Oulianov

Crowell

Gosztola

et al. 2007

Journal of Applied Physics

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We report the first ultrafast pulse radiolysis transient absorption spectroscopy measurements from the Terawatt Ultrafast High Field Facility (TUHFF) at Argonne National Laboratory. TUHFF houses a 20 TW Ti:sapphire laser system that generates 2.5 nC sub-picosecond pulses of multi-MeV electrons at 10 Hz using laser wakefield acceleration. The system has been specifically optimized for kinetic measurements in a pump-probe fashion. This requires averaging over many shots which necessitates stable, reliable generation of electron pulses. The latter were used to generate excess electrons in pulse radiolysis of liquid water and concentrated solutions of perchloric acid. The hydronium ions in the acidic solutions react with the hydrated electrons resulting in the rapid decay of the transient absorbance at 800 nm on the picosecond time scale. Time resolution of a few picoseconds has been demonstrated. The current time resolution is determined primarily by the physical dimensions of the sample and the detection sensitivity. Subpicosecond time resolution can be achieved by using thinner samples, more sensitive detection techniques and improved electron beam quality.

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“…This operational regime is called the self modulated laser wakefield acceleration (SM-LWFA). Although experiments with such high energy, high power, sub-picosecond Nd:glass based lasers (for example, 250 TW in 650 fs [27], τ L τ p ) are still actively being pursued [27][28][29][30][31][32][33][34][35][36][37][38][39], the majority of research has shifted to experiments with shorter pulse duration (τ P τ L 100 fs), higher repetition rate Ti:Sapphire based CPA laser systems [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55]. Experimental setups for SM-LWFA experiments were simple and similar everywhere.…”

Section: Plasma Based Accelerator Experimentsmentioning

confidence: 99%

“…To detect the relativistic electron, a variety of detectors have been employed: surface barrier detectors (SBD) [16,25,26,48], scintilators with photomultipliers (scintillator-PMP) [28,33,51,158], cloud chambers [16], Cerenkov radiation imaged by a camera [88], thermoluminescent dosimeters (TLD) [55], scintillating fibers [159,160], Radiochromic film [161], imaging plates (IP) [57,60,64,65,162], and scintillating (or phosphor) screens, mostly Gadox (Gd 2 O 2 S : Tb) [163] with films [26] or cameras (scintillator-camera) [16,28,39,53,56,63,72,164]. Detection by a SBD and scintillator-PMP were popular methods in early LWFA experiments due to their high sensitivity.…”

Section: Spectrometer Designmentioning

confidence: 99%

Control of Laser Plasma Based Accelerators up to 1 GeV

Nakamura

2007

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This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs.An ESM specialized for CDG-LWFAs with an unprecedentedly wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and output laser properties as well as a large angular acceptance (> ±10 mrad) were realized by employing a slitless scheme. A scintillating screen (LANEX Fast back ,LANEX-FB) -camera system allowed faster than 1 Hz operation and evaluation of the spatial properties of e-beams. The design provided sufficient resolution for the whole range of the ESM (below 5% for beams with 2 mrad divergence).The calibration between light yield from LANEX-FB and total charge, and a study on the electron energy dependence (0.071 to 1.23 GeV) of LANEX-FB were performed at the Advanced light source (ALS), Lawrence Berkeley National Laboratory (LBNL). Using this calibration data, the developed ESM provided a charge measurement as well.The production of high quality electron beams up to 1 GeV from a centimeter-scale ii accelerator was demonstrated. The experiment used a 310 µm diameter gas-filled capillary discharge waveguide that channeled relativistically-intense laser pulses (42 TW, A statistical analysis of the CDG-LWFAs' performance was carried out. By taking advantage of the high repetition rate experimental system, several thousands of shots were taken in a broad range of the laser and plasma parameters. An analysis program was developed to sort and select the data by specified parameters, and then to evaluate performance statistically.The analysis suggested that the generation of GeV-level beams comes from a highly unstable and regime. By having the plasma density slightly above the threshold density for self injection, 1) the longest dephasing length possible was provided, which led to the generation of high energy e-beams, and 2) the number of electrons injected into the wakefield was kept small, which led to the generation of high quality (low energy spread) e-beams by minimizing the beam loading effect on the wake. The analysis of the stable half-GeV beam regime showed the requirements for stable self injection and acceleration. A small change of discharge delay t dsc , and input energy E in , significantly affected performance.The statistical analysis provided information for future optimization, and suggested possible schemes for improvment of the stability and higher quality beam generation. A CDG-LWFA is envisioned as a construction block for the next generation accelerator, enabling significant cost and size reductions.

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Quasimonoenergetic electron beam generation by using a pinholelike collimator in a self-modulated laser wakefield acceleration

Cited by 24 publications

References 18 publications

Measuring the magnetic field of a magnetized plasma using Raman scattering

Measuring the magnetic field of a magnetized plasma using Raman scattering

Ultrafast pulse radiolysis using a terawatt laser wakefield accelerator

Control of Laser Plasma Based Accelerators up to 1 GeV

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