Solid polystyrene and deuterated polystyrene light output response to fast neutrons

Area of Science:

• Nuclear Fusion Diagnostics
• Materials Science for Neutron Detection
• High-Energy Physics Instrumentation

Background:

• The Neutron Imaging System is crucial for diagnosing deuterium-tritium (DT) implosion characteristics at the National Ignition Facility (NIF).
• Current systems use polystyrene scintillating fibers to detect fusion neutrons, but increasing yields and the need for 3D information necessitate upgrades.
• Next-generation systems are being developed to enhance diagnostic capabilities for fusion research.

Purpose of the Study:

• To investigate a novel neutron imaging system utilizing deuterated polystyrene (CD) fiber arrays.
• To compare the performance of CD fibers with standard hydrogen-based polystyrene (CH) fibers for neutron detection.
• To evaluate the potential of CD fibers for improved imaging resolution in fusion diagnostics.

Main Methods:

• Experimental tests were conducted using 14 MeV fusion neutrons from DT capsule implosions at the OMEGA laser facility.
• Relative light output measurements were performed for deuterated polystyrene and standard polystyrene scintillators.
• Neutron response data across a wide energy range (1-800 MeV) were collected at the Weapons Neutrons Research Facility.

Main Results:

• The study compares the light output and neutron response of deuterated polystyrene (CD) and standard polystyrene (CH) scintillators.
• Previous studies indicated potential resolution improvements with deuterated materials, but also reduced light output.
• Experimental data on relative light output and neutron response are presented for these materials.

Conclusions:

• Deuterated polystyrene offers potential for enhanced neutron imaging resolution in fusion diagnostics.
• Further research is needed to balance improved resolution with acceptable light output for practical applications.
• The findings contribute to the development of advanced diagnostics for high-yield fusion experiments.