Numerical and experimental characterization of a plasma induced on a solid target by an intense pulsed multi-MeV e-beam

Abstract

We investigate the interaction of an intense pulsed multi MeV electron beam with a solid target on the ASTERIX high voltage generator using a set of numerical and experimental tools. Physical mechanisms occurring at various stages are examined, from electron beam dynamics to X-ray production, including plasma generation at the solid target surface. First, the electron beam characteristics are determined using 2D axisymmetric Particle-In-Cell calculations and a good agreement is found between calculated and measured current and voltage profiles. Calculated electron beam characteristics serve as an input to a 3D Monte-Carlo code in order to simulate the dose distribution within the solid target. The plasma produced at the target surface upon interaction with the electron beam is diagnosed and quantitatively characterized through UV-visible emission spectroscopy. Plasma species are identified and spectroscopy data are analyzed based on a 1D radiative transfer model, allowing electron density and temperature profiles to be inferred. Such combined numerical and experimental investigation is promising for gaining insight into physical mechanisms occurring upon the interaction between high energy electrons and solid targets.

Characterization of electrostatic discharge induced plasmas in dielectrics irradiated by multi-MeV electron beam

“…For this calculation, the expansion velocity v expan is set to 150 km/s and r 0 ¼ 100 S/m. Equation (6) shows that the expansion velocity is an important parameter of the model. To determine it, we first analyze the measured signals, which show that a transmission minimum is systematically observed at the end of the ESD, i.e., at the average values of 620 and 750 ns after the beginning of the phenomena, respectively, PE and PTFE.…”

“…In the case of the ablation plasma, it has been shown that a low ionized plasma surrounds this hot core and is about twice as large as the size of the inner core. 6,[36][37][38][39] So, the magnitudes of the expansion velocities determined from the optical imagery may underestimate the expansion velocity of the low ionized region of the plasma.…”

“…These effects can occur in satellites as well as in a broad range of electronic parts integrated within diagnostics used while operating facilities such as nuclear power plants, particle accelerators, 1 high energy, 2 high power 3 laser beams, and high pulsed power electron or X-ray beams. [4][5][6][7] These ESDs may significantly affect the electric signals associated with the measurements, thus inducing misinterpretation. ESDs may also induce thermomechanical degradation.…”