Modelling of a digital radiography chain based on a laser-plasma accelerator

lazar, safir; Ecole polytechnique; France

Azamoum, Y.; Université Paris-Saclay; France
Gallé, G.; Université Paris-Saclay; France
Lazar, S.; Université Paris-Saclay; France
Lifschitz, A.; Université Paris-Saclay; France
Rousseau, J.P.; Université Paris-Saclay; France
Sylla, F.; SourceLAB SAS; France

ID: ECNDT-0316-2018
Session: X-ray & CT modeling 1
Room: G3
Date: 2018-06-14
Time: 09:20 - 09:40

Laser-plasma accelerators generate ultra-short electron beams (few fs duration) with energies ranging from the MeV to hundreds MeVs and micrometric radial size. By converting electrons to high energy gamma radiation, these accelerators make possible the imaging of dense and thick objects. The source size, less than 50 um allows to have fine resolutions. A tomograph based on this type of source is under construction at the LOA laboratory. Along with this experimental facility, a platform for end-to-end numerical modelling of the tomograph is being developed, which will be presented here. The platform will be useful for predicting and interpreting the experimental results, and to optimize the different parts of the tomograph. The modelling requires the coupling between Particle-in-Cell calculations of the laser-plasma accelerator and a Monte Carlo code for the interaction of high energy gamma rays with the object being inspected.

The transport of gammas is calculated with a Full Monte Carlo code, including the whole shower of secondary particles (electrons and positrons). This kind of calculation not relying in perturbative approximations is time consuming for complex or thick objects. To speed up the calculations, the Monte Carlo code was natively written in GPU using the Optix library. In a second step, the interaction of the radiation with the digital detector is modelled with the data coming from a parametric study of the impulse response of the detector at different energies. This allows us to quickly test different configurations of detector and metallic screens for a given object.