Differentiating multi-MeV, multi-ion spectra with CR-39 solid-state nuclear track detectors.

Area of Science:

• * Nuclear Physics and Laser-Matter Interactions
• * Particle Detection and Spectroscopy

Background:

• * High-intensity petawatt lasers enable ion acceleration and nuclear fusion research.
• * CR-39 detectors are used for ion yield measurement but struggle with multi-ion spectra differentiation due to overlapping track data and non-unique particle energy-diameter relations.
• * Existing image recognition algorithms for CR-39 data can lead to misinterpretation.

Purpose of the Study:

• * To develop an improved algorithm for CR-39 detector image processing, reducing user bias.
• * To establish high-sensitivity, multi-species particle spectroscopy using CR-39 detectors.
• * To validate the enhanced CR-39 spectroscopy method against established diagnostic tools.

Main Methods:

• * Developed a novel algorithm to minimize user bias in CR-39 track image analysis.
• * Calibrated CR-39 detector response for protons, carbon, and helium ions (0.1-10 MeV).
• * Employed a forward-fitting procedure with multiple, differently filtered CR-39 detectors and statistical energy loss fluctuation measurements.

Main Results:

• * Achieved high-sensitivity, multi-species particle spectroscopy for protons, carbon, and helium ions.
• * Validated the CR-39 method by demonstrating agreement with Thomson parabola ion spectrometer data.
• * Successfully detected alpha particles from laser-driven proton-boron fusion reactions amidst high proton and carbon backgrounds.

Conclusions:

• * The developed CR-39 analysis method overcomes limitations in differentiating multiple ion species.
• * This technique enables accurate multi-species particle spectroscopy in laser-driven fusion experiments.
• * The validated method provides a sensitive tool for detecting specific fusion products like alpha particles.