Implementation of scattering pinhole diagnostic for detection of fusion products on CR-39 at high particle fluence

Abstract

Many Inertial Confinement Fusion (ICF) experiments use solid-state nuclear track detector CR-39 as a means to detect different types of nuclear products. Until recently, it was difficult to use CR-39 in experiments with very high yields because particle tracks would overlap. A scattering pinhole has been implemented in order to reduce the fluence on the CR-39. This paper details the design and implementation of a scattering pinhole to detect protons born from D3He nuclear reactions: D +3 He = p+(14.7MeV) + [alpha](3.7MeV). To do so, basic models relating the scattering angle to material thickness and atomic number were developed. The scattering pinhole reduced the fluence on the CR-39 enough to successfully count all the tracks and calculate a product yield. A proton yield of 2.25e10 t 0.17e10 was calculated and falls within half a standard deviation of the proton yield found with the Wedge Range Filter (WRF) spectrometer, the value being 2.19e10. The image on the CR-39 was predicted to be s = 0.957mm t 0.092mm. This correlates with measured size [sigma] = 0.873mm, supporting the validity of the models. To further explore the nuclear this nuclear reaction, the design challenges for detecting 3.7MeV alpha particles was also explored.