On the possibility of electron degeneracy diagnostics in laser-imploded DT fuel for fast ignition

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 ⁹Be(α, nγ)¹²C governed by fusion-produced energetic alpha-particles in a laser-imploded DT fuel pellet admixed with a small amount of ⁹B. 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 α + ⁹Be reaction occurs during the slowing down of α-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.