ParaTAXIS X-ray Scattering Input & Output

This dataset describes the science case of the SIMEX platform tool chain for EUCALL WP4 Milestone M4.3.

The file opt_thick_1.6x1.6x3_micron_10fs_around_laser_max.h5  contains the ParaTAXIS density input data in openPMD format for the optically thick case (milestone 4.2.2.10). The data was obtained in a 2D PICLS simulation (milestone 4.2.2.7) which modeled the temporal evolution of a silicon grating irradiated by a \(\tau_\mathrm{FWHM} = 83\,\mathrm{fs},\ \lambda = 800\,\mathrm{nm}\) laser pulse of normalized amplitude \(a_0 = 0.25\). Here 959 slices which correspond to subsequent PIC time steps of length \(\Delta t_\mathrm{PIC} = 1.042 \cdot 10^{-17}\,\mathrm{s}\) were stacked in propagation direction of the XFEL probe pulse thus taking time evolution of the target during X-ray pulse propagation into account.  ParaTAXIS reads the density into a simulation volume of 1024 x 512 x 512 cells. The cell sizes of the PIC and the ParaTAXIS simulations are equally \(3.125\,\mathrm{nm}\) in every spatial direction. Density data is given in units of critical densities with respect to the \(800\,\mathrm{nm}\) laser. One critical density corresponds to \(n_\mathrm{c} = 1.7422 \cdot 10^{27}\,\mathrm{m}^{-3}\). The time window chosen is situated from \(5\,\mathrm{fs}\) before until \(5\,\mathrm{fs}\) after the optical laser main pulse maximum hits the foil indicating a delay of \(\Delta t = 0\). The optical laser incidence is in z-direction (ParaTAXIS coordinates) under 0°.

The total illuminated area for both the optically thick and thin cases was \(1.6 \times 1.6\, \mathrm{\mu m}\). We assume a target thickness of \(3\,\mathrm{\mu m}\). The detector distance was \(d = 1.4\,\mathrm{m}\) and the detector pixel size was \(a_\mathrm{D} = 13.5\,\mathrm{\mu m}\). For Thomson scattering most photons are scattered in forward direction. We therefore assumed a maximum polar scattering angle of \(0.01\,\mathrm{rad}\) in order to increase statistics on the detector.

Via 16 simulations we obtained the detector outputs in the optically thick case which can be found in opt_thick_run__detector__photons.h5 in openPMD format.

The file opt_thin_integrated_1.6x1.6x3_micron_10fs_around_laser_max contains the total electron density data for the optically thin case (milestone 4.2.2.9) integrated over 959 slices in the propagation direction of the probe laser beam. The density is only non-zero in the 6th cell of the simulation volume thus enforcing single-scattering in the ParaTAXIS simulation as can be assumed for an optically thin medium. This data was read by a ParaTAXIS into a simulation volume of 12 x 512 x 512 cells.

We launched 10 parallel simulations, each arriving at detector images for \(10^{12}\) simulated photons. The detector output of these simulations can be found in opt_thin_detector_1e12_photons_run.h5 also in openPMD format.