Areal density diagnostics using suprathermal fusion reaction for laser-imploded D-T pellets

摘要

Detecting highly energetic neutrons produced by suprathermal fusion reactions is expected as a useful method for the areal density diagnosis in future ICF experiments. This paper examines the possibility of rho R diagnosis using suprathermal fusions, on the basis of transport calculations for neutrons and charged particles. Not only neutron elastic scattering but also nuclear elastic scattering of alpha-particles are considered as the processes producing energetic recoil ions. Since the suprathermal fusion reaction is affected by the plasma temperature through the slowing-down process of energetic alpha-particles and recoil ions, the yield ratio of highly energetic neutrons emitted from suprathermal fusions to total ones depends considerably on the temperature. An areal density diagnostic method based on neutron spectroscopy is proposed here that can eliminate the influence of the plasma temperature on the determination of the areal density. Moreover, on the basis of coupled transport/hydrodynamic calculation, we derive a more realistic energy spectrum of neutrons escaping from laser-imploded D-T pellet and examine the usefulness of the diagnosis method proposed in this paper. It is shown that the method proposed here may be useful for the areal density diagnosis in the ignition-grade ICF pellets. [References: 18]