Global Characterization of a Laser-Generated Neutron Source

TL;DR

This paper provides a comprehensive experimental characterization of laser-generated neutron sources using the Titan laser, measuring neutron yields and angular distributions with multiple diagnostics.

Contribution

It introduces a multi-diagnostic approach for robustly characterizing laser-driven neutron emissions and reports the first detailed measurements of neutron yield and angular dependence in this context.

Findings

Neutron yield of approximately 2×10^9 neutrons per shot.

Modest angular dependence of neutron emission close to simulations.

Validation of diagnostic methods for neutron source characterization.

Abstract

Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23 $\mu m$ thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, Time-of-Flight detectors and direct measurement of $^{7}$Be residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of $2.10^{9}$ neutrons per shot with a modest angular dependence, close to that simulated.