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

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.