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内容記述 |
At present, high-power laser could accelerate particles of ions and electrons up to several tens MeV and several GeV, respectively, through laser plasma interactions. Neutrons are also generated by the secondary reactions. These laser driven particles have remarkable features of short pulse, high flux in a single shot, and continuous energy. These features are suitable for the study of nuclear astrophysics. Laser neutron sources been developed in various facilities such as LANL and LLNL in the world. We have also generated high flux neutrons by the secondary nuclear reactions of laser accelerated protons (deuterons) on Be targets using LFEX laser at Osaka University. The maximum flux of a single neutron pulse reached to 10^11 neutrons/shot. This opens an analysis using a single neutron pulse. The energy spectra of the primary pulses of protons and deuterons accelerated by the laser could be measured by Tomson parabola spectrometers. The energy spectra of the neutrons could be measured by a time-of-flight method for each shot. We have measured neutron flux using activation methods. The laser driven neutron source is suitable for the study of nucleosyntheses such as AGB s-process and massive star s-process (C shell burning) as well as neutron burst recorded in isotopic abundances in primitive meteorites. Furthermore, this is useful for the study of interactions with cosmic neutrons. We discuss the development of laser driven neutron source, results using activation methods and neutron absorption resonances and vison for nuclear astrophysics study. |
