Response of CR-39 nuclear track detectors to protons with non-normal incidence
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20ja084_full.pdf
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2.57 MB
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Checksum (MD5)
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Author(s)
Przybocki, Ryan
Gatu Johnson, Maria
Sutcliffe, G.
Lahmann, Brandon
Séguin, Frederick H.
Frenje, Johan A.
Adrian, Patrick J.
Johnson, Timothy M.
Pearcy, Jacob A.
Kabadi, Neel V.
Date Issued
September 2020
Journal
Review of Scientific Instruments
Publisher
AIP
Abstract
This paper presents data from experiments with protons at non-normal incidence to CR-39 nuclear track detectors, analyzing the properties of detection efficiency, proton track diameter, track contrast, and track eccentricity. Understanding the CR-39 response to protons incident at an angle is important for designing charged particle detectors for inertial confinement fusion (ICF) applications. This study considers protons with incident energies less than 3 MeV. In this regime, an incident angle of 10° has no effect on CR-39 detection efficiency, and >85% detection efficiency is preserved up through 25° in the range of 1.0 MeV–2.1 MeV. For ICF applications, incident angles above 30° are deemed impractical for detector design due to significant drops in proton detection at all energies. We observe significant reductions in detection efficiency compared to theoretical predictions, particularly at low energies where proton tracks are etched away. The proton track diameter measured by the scan system is observed to decrease with higher incident angles. The track diameters are analyzed with two fitting models, and it is shown that the diameter–energy relation can be fit with the existing models at angles up to 30°. The optical contrast of the tracks tends to increase with the angle, meaning that the tracks are fainter, and a larger increase is observed for higher energies. Eccentricity, a measure of how elongated proton tracks are, increases with the incident angle and drops after the critical angle. The lowest energy tracks remain nearly circular even at higher angles.
Description
Submitted for publication in Review of Scientific Instruments
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1063/5.0029230
