X-ray, Gamma and Neutron Diagnostics Requirements for Projectile Driven Inertial Confinement Fusion

• Published in: 2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and International Symposium on Room-Temperature Semiconductor Detectors (NSS MIC RTSD) p. 1
• Main Authors: Pesic, Z., Escauriza, E., Burdiak, G., Doyle, H., Hawker, N.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 04-11-2023
• Subjects: Inertial confinement; Neutrons; PIN photodiodes; Production; Projectiles; Semiconductor detectors; Silicon
• ISSN: 2577-0829
• DOI: 10.1109/NSSMICRTSD49126.2023.10337817

First Light Fusion is researching inertial confinement fusion (ICF) with a one-sided pressure drive. To create the extreme temperatures and pressures required for fusion, we use unique targets: an 'amplifier' boosts the pressure generated by the projectile impact and creates convergence, imploding the fuel capsule from many directions.Our experimental facilities include a two-stage light-gas gun ('BFG') and a 140 kV, 9 MA electromagnetic pulsed-power driver (Machine 3 or M3). The company is also intensively working on designing the next generation pulsed power machine, the 100 MJ M4, to demonstrate ignition.In 2022 First Light Fusion validated neutron production from projectile-driven DD and DT fusion on the BFG [1], [2]. The first part of this contribution will focus on our current neutron and x-ray diagnostic capabilities. We fielded scintillation detectors at distances between 1-2 m from the fusion targets, which provides n-TOF and validates the energy of neutrons. Filtered Si PIN diodes are used as x-ray flux diagnostics to roughly estimate the electron temperature in the fuel. The temporal profile of the detected x-rays provides information about fuel compression.In the second part of this contribution, we will present an overview of the nuclear diagnostic requirements for the planned M4 machine. These requirements are driven by fusion products that need to be detected to gain understanding of the physics relevant to ignition [3], [4]. For example, our primary diagnostics goal is to be able to diagnose energetic DD and DT neutrons and a high energy x-rays and gammas that can escape from the extremely dense fuel without being attenuated by high-Z materials surrounding the fuel capsule. Physical quantities of interests are the total neutron yield which can be determined using activation foils, fuel ion temperature which can be inferred from n-TOF and burn duration from the fusion gamma intensity profiles.