A Geant4 simulation of X-ray emission for three-dimensional proton imaging of microscopic samples

Accuracy of three-dimensional proton imaging of an inertial confinement fusion target assessed by Geant4 simulation

“…The simulation configuration was validated in previous studies for steady beam PIXE analysis, based on the Geant4 TestEm5 example [16][17][18]. We used the same physics models in our codes for STIM-T and PIXE-T simulations: Livermore models and Bearden's X-ray energy database were applied, as they were found more accurate for simulations at low energy.…”

“…It was also checked that, as expected, this energy limitation did not affect the proton energy loss. This threshold was shown to significantly reduce the simulation time [18]. In these conditions, it took about 5 days for a PIXE-T simulation of 100 projections × 1 slice × 128 pixels on a multicore computer with 100 threads, 2.7 GHz, 768 Gb RAM.…”

“…MLEM is often used for PIXE-T as a robust algorithm even with noisy and/or incomplete data [6,19,20]. The images presented in this study were obtained from 32 iterations, which was the optimal number determined from Normalized Average Absolute Deviation (NAAD) and Normalized Root Mean Squared Deviation (NRMSD) calculations [18].…”

“…For example, for TomoRebuild, using a very basic PC 3.4 GHz, 8 Go RAM, it takes 1 minute to reconstruct a full 3D STIM-T image of 128x128x128 voxels using TR_FBP, and 25 minutes using TR_MLEM. For PIXE-T, it takes 2 minutes for one slice, including the calculation of the NLXP and XA correction matrix, for which the large detection solid angle is modelled by finely discretizing the entrance window of the detector [18]. For JPIXET, both STIM-T and PIXE-T reconstructions are performed together.…”

“…A new advanced example for the specific application of 3D imaging of microscopic samples is being developed at CENBG/LP2I Bordeaux. For this, several phantoms dedicated to biological applications were developed, including the upper part of a Caenorhabditis elegans nematode derived from experimental data [17,18]. In the present study, we constructed a numerical ICF target phantom with uniform composition and mass density.…”