Search

A new method to diagnose the degree of electron degeneracy in compressed fuel for fast-ignition inertial confinement fusion is proposed We focus on 4.44-MeV γ-rays emitted in the reaction 9 Be(a, nγ) 12 C governed by fusion-produced energetic alpha-particles in a laser-imploded DT fuel pellet admixed with a small amount of 9 B. In this case the compressed fuel pellet is not subjected to any heating laser pulse. We have evaluated the probability P α-Be that the a+9B e reaction occurs during the slowing down of a-particle. It is found that the reaction probability depends strongly on the degeneracy parameter Θ, which is defined as the ratio of electron temperature to the Fermi energy. We show the possibility of diagnosing the electron degeneracy from the P α-Be - Θ diagram by detecting the 4.44-MeV γ-quanta and DT neutrons emitted from the dense core plasma.

The potentiality of electron degeneracy diagnostics based on γ-ray measurement is discussed. For this purpose, the nuclear reactions D (α, γ)6Li and T (α, γ)7Li are considered. These reactions are induced in DT plasma by fusion-born energetic α-particles and proceed through the excited nuclei 6Li* and 7Li* emitting monochromatic γ-quanta with 2.186-MeV and 0.478-MeV energies, respectively, in their decay to the ground state. If the plasma is being highly compressed and the electrons are in degenerate state, then the stopping range of the α-particles is lengthened compared with the case of non-degenerate electron plasma. As a result, the probability that a fusion-born α-particle will undergo D (α, γ) or T(α, γ) reaction during slowing down would be enhanced. In this paper we will discuss the feasibility of detecting the 2.186-MeV and 0.478-MeV γ-ray in ICF environment.