LNF

Gas target experiments

 

Self-injection experimental set-up

Nowadays, plasma wakefield acceleration is a promising acceleration technique for compact and cheap accelerators, needed in several fields, e.g., novel compact light sources for industrial and medical applications. Indeed, the high electric field available in plasma structures (>100 GV/m) allows for accelerating electrons at the GeV energy scale in a few centimeters. At FLAME we are working in this direction thank to the so called Laser Wakefield Acceleration (LWFA) mechanism: a highly intense (1018 W/cm2) femtosecond laser can induce waves into a plasma and, thanks to its ponderomotive force, it can inject some electrons that, in turn, get accelerated. This is called self-injection regime (some reference experiments can be found here, here and here). Recently, we have successfully accelerated relativistic electron bunches by employing the FLAME laser to ionize a gas (He2 or N2), injected in the target area by a 2 mm super-sonic nozzle, in a highly non-linear regime. The electron bunches have been characterized in charge (10 pC), transverse size, angular divergence and energy (250 MeV with 20% spread), while the plasma density, measured by means of a Mach–Zehnder interferometer, was equal to 1×1019 cm−3.

 

 

FLAME gas-jet

This source has been employed to study new single-shot diagnostics, exploiting both the betatron radiation emitted in the plasma channel and the Transition Radiation (TR) generated by a charged particle passing through the boundary between two media with different refractive index. In particular, by measuring at the same time the electron energy and the betatron X-ray spectrum, we have developed an innovative, single-shot, non-intercepting monitor of the transverse profile of plasma-accelerated electron beams, allowing to perform measurement with nanometric resolution. Moreover, betatron radiation has been studied also for single-shot emittance measurements of electron bunches from LWFA inside the plasma bubble.

 

Furthermore, we are working on new acceleration schemes based on plasma structures, but providing good quality electron beams. In particular, a new experimental beamline for external injection acceleration is currently under development at SPARC_LAB. In this scheme, a pre-existing electron bunch, produced by a high brightness photoinjector, is accelerated by the plasma wakefield excited by a high power laser, aiming to preserve the beam quality as much as possible. At FLAME the use of a capillary to host this interaction has been studied and a matching condition between the capillary radius and a super-Gaussian-like laser has been found.

 

Publication highlights:

  • “Characterization of X-ray radiation from solid Sn target irradiated by femtosecond laser pulses in the presence of air plasma sparks”, A. Curcio et al., Laser and Particle Beams, vol. 34 (2016) pag. 533, doi: 10.1017/S0263034616000458
  • “Laser–capillary interaction for the EXIN project”, F. G. Bisesto et al., Nucl. Instr. Meth. Phys. Res. A vol. 829 (2016) pag. 309, doi: 10.1016/j.nima.2016.01.037
  • “First measurements of betatron radiation at FLAME laser facility”, A. Curcio et al., Nucl. Instr. Meth. Phys. Res. B vol. 402 (2017) pag. 388, doi: 10.1016/j.nimb.2017.03.106
  • “Single-shot non-intercepting profile monitor of plasma-accelerated electron beams with nanometric resolution”, A. Curcio et al., Appl. Phys. Lett. vol. 111 (2017) pag. 133105, doi: 10.1063/1.4998932
  • “Trace-space reconstruction of low-emittance electron beams through betatron radiation in laser-plasma accelerators”, A. Curcio et al., Phys. Rev. Accel. Beams vol. 20 (2017) pag. 012801, doi: 10.1103/PhysRevAccelBeams.20.012801
  • “Innovative single-shot diagnostics for electrons from laser wakefield acceleration at Flame”, F. G. Bisesto et al., J. of Phys.: Conf. Series, vol. 874 (2017) pag. 012035, doi: 10.18429/JACoW-IPAC2017-TUPIK022
  • “Novel single-shot diagnostics for electrons from laser-plasma interaction at SPARC_LAB”, F. G. Bisesto et al., Quantum Beam Science, vol. 1 (2017) pag. 13, doi: 10.3390/qubs1030013
  • “Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB”, G. Costa et al., Nucl. Instr. Meth. Phys. Res. A vol. 909 (2018) pag. 118, doi: 10.1016/j.nima.2018.02.008
  • “Ray optics hamiltonian approach to relativistic self focusing of ultraintense lasers in underdense plasmas”, A. Curcio et al., EPJ Web of Conferences, vol. 167 (2018) pag. 01003, doi: 10.1051/epjconf/201816701003
  • “Recent studies on single-shot diagnostics for plasma accelerators at SPARC_LAB”, F. G. Bisesto et al., Nucl. Instrum. and Meth. in Phys. Res. A, vol. 909 (2018) pag. 364, doi: 10.1016/j.nima.2018.02.059
  • “Consolidating multiple femtosecond lasers in coupled curved plasma capillaries”, A. Zigler et al., App. Phys. Lett., vol. 113 (2018) pag. 183505, doi: 10.1063/1.5046400
  • “Towards the detection of nanometric emittances in plasma accelerators”, A. Curcio et al., J. of Instrum., vol. 14 (2019) pag. C02004, doi: 10.1088/1748-0221/14/02/C02004
  • “Modeling and diagnostics for plasma discharge capillaries”, A. Curcio et al., accepted for publication on Physical Review E.

 

Contact person: M. P. Anania, Maria.Pia.Anania@lnf.infn.it, tel. (+39) 069403 2947

 

Last update 12/2018