Speaker
Description
Physics of high power, ultra-intense lasers interacting with plasma is a field that dramatically evolved in the last years, with a growing number of multi-TW and PW-class dedicated facilities around the world. In a such scenario an optimized shielding assessment still appears to be a challenge: if on one hand the constant technological improvements are allowing increased energies and intensities of the emitted ionizing radiation, on the other hand some aspects of the underlying physical phenomena still need more investigation.
In this work the shielding concept for two different, complex laser-induced radiation fields will be presented, as significant cases:
(1) After accurate investigation of the dynamics of hot refluxing electrons in the interaction of an ultra-short relativistic laser pulse with a thin foil target via particle-in-cell (PIC) simulations, and comparison with experimental data, the typical Bremsstrahlung source term has been evaluated, taking into account for the first time the photon radiation emitted from the recirculating electrons in the plasma. This source term primarily drives the radiation protection assessment in the facilities dedicated to the investigation of the matter under extreme conditions.
(2) The shielding concept of the ATHENA Lab, which is at present in construction at HZDR and will use the PENELOPE PW laser for biology and medical applications, will be presented. The shielding assessment has been realized considering two different operation modes: (a) a ‘full energy’ mode, where we assume that the full energy spectrum of interest for the biology/medical applications (up to 250 MeV) is reached via advanced acceleration schemes; (b) a ‘routine operation’ mode, with a lower, stable working point as maximum proton energy (100 MeV). The data-driven source terms used, together with the optimization process, will be described and discussed.