X-ray sources using a picosecond laser driven plasma accelerator

Abstract

X-ray photon beams in the keV to MeV energy range are essential to study high energy density (HED) matter and to improve the understanding of inertial confinement fusion and astrophysical systems. HED experiments produce highly transient matter under extreme states of temperatures and pressures and it is essential to develop light sources that are: in the hard x-ray energy range (0.01-1 MeV), directional, high-yield, low-divergence, and short-duration (ps and sub-ps). In this work we show that by using a laser plasma accelerator (LPA) driven by a kJ-ps class laser it is possible to generate a broadband (0.01-1 MeV) hard x-ray source that satisfies the previous requirements. A series of experiments were conducted on the Titan laser at Lawrence Livermore

Microcoulomb (0.7 ± $$\frac{0.4}{0.2}$$ μC) laser plasma accelerator on OMEGA EP

“…This divergence demonstrates a major step forward in the possible quality of electron beams from SMLWFA since it is significantly reduced from the next best divergence reported from other SMLWFA experiments (64 × 100 mrad ± 10 mrad 6 ) and is on the order of the divergences (< 10 mrad) of the electron beams produced by LWFA being driven by ultrashort-pulse lasers (τ < λ p ). The possibility of lower-divergence electron beams from SMLWFA-based LPAs increases their utility when using the produced electron beams to generate compact sources of high-energy electrons for conversion to photons and positrons.…”

“…For the lowest-divergence electron beam reported here, that source size would be approximately half of that produced by the electron beam from Ref. 6 . Lower-divergence electron beams also reduce the background noise in these applications.…”

Stable and high quality electron beams from staged laser and plasma wakefield accelerators

“…At densities around 10 18 cm −3 the acceleration gradient in these accelerators is thus several orders of magnitude higher than the breakdown fields in conventional radio-frequency (RF) accelerators (∼ 100 MV m −1 ), al-lowing for a significant downsizing of the accelerator. LWFA experiments are routinely performed at numerous high-power laser facilities [3][4][5][6][7][8][9][10][11] and reach high charge (∼ nC) [12,13] combined with an ultra-short bunch duration (∼ 10 fs) [14,15], resulting in high peak currents of tens of kA [13,16]. Furthermore, the bunches typically have a few-micrometer source size at the exit of the accelerator [17][18][19], which is paired with few-mrad divergence [12,20].…”

Whole-beam self-focusing in fusion-relevant plasma

“…In underdense plasma, hydrodynamic expansion of an optical field-ionized plasma column forms a low-density channel which has been proposed [ 1 ] and demonstrated [ 2 ] as a method of guiding high-power driving pulses to obviate the need for capillary guiding structures in high-energy laser Wakefield accelerators. Further, Lemos et al [ 3 ] demonstrated production of betatron radiation and inverse Compton scattering from the interaction of picosecond-scale laser pulses with a supersonic gas jet (and in the latter case, a plasma mirror). Future applications of this work will be heavily reliant on the reliable direction of the outgoing radiation.…”