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M. Ganciu

Publications and source records attributed to M. Ganciu.

2 recordsLinked to original sources

Radiation dose simulation during laser-plasma proton acceleration experiments and method to increase the measurement resolution of the proton energy spectrum

The paper discusses some 3D simulations to compute the ionizing radiation dose during laser-plasma experiments leading to the generation of accelerated protons and electrons. Also, we suggest a new method to increase the measurement resolution of the proton energy spectrum. Monte-Carlo simulations of the radiation doses map around the laser-foil interaction point are performed using Geant4 General Particle Source code and the particular geometry chosen for the experimental setup. We obtain the map of the radiation dose distribution for high-power laser - thin solid target experiments, considering a cubic geometry of the interaction chamber. The computed radiation dose distribution shows a good agreement with various, previously obtained experimental results, and could be a step towards simulating the radiation environment inside of a spacecraft. To characterize the laser-plasma accelerated protons, we introduce a new method to enhance the measurement resolution of the proton energy spectrum by employing a stack of thin solid detectors, preferably CR-39. Each detector is thinner than the Bragg peak region on the Bragg curve that characterizes the loss of kinetic energy as a function of the particle penetration depth in the detector material. The relevance of this method for space radiation characterization and cybersecurity insurance is highlighted.

physics.ins-det

Coupling of (ultra-)relativistic atomic nuclei with photons

The coupling of photons with (ultra-) relativistic atomic nuclei is presented in two particular circumstances: very high electromagnetic fields and very short photon pulses. We consider a typical situation where the (bare) nuclei (fully stripped of electrons) are accelerated to energies ~1TeV per nucleon (according to the state of the art at LHC, for instance) and photon sources like petawatt lasers \simeq1eV -radiation (envisaged by ELI-NP project, for instance), or free-electron laser ~10keV -radiation, or synchrotron sources, etc. In these circumstances the nuclear scale energy can be attained, with very high field intensities. In particular, we analyse the nuclear transitions induced by the radiation, including both one- and two-photon processes, as well as the polarization-driven transitions which may lead to giant dipole resonances. The nuclear (electrical) polarization concept is introduced. It is shown that the perturbation theory for photo-nuclear reactions is applicable, although the field intensity is high, since the corresponding interaction energy is low and the interaction time (pulse duration) is short. It is also shown that the description of the giant nuclear dipole resonance requires the dynamics of the nuclear electrical polarization degrees of freedom.

nucl-th