Impact of x rays on the sensitivity of CR-39 detectors to 2.4-MeV protons
Name
073506_1_5.0272809.pdf
Description
Published version
Size
4.85 MB
Format
Adobe PDF
Checksum (MD5)
e8fcef6e2d9f07a4ea56b66f7c385e57
Author(s)
Kishimori, R
Cufari, M
Zhong-Johnson, EZL
Buschmann, BI
Sinskey, AJ
Johnson, TM
Vanderloo, N
DeVault, A
Foo, BC
Vargas, J
Date Issued
July 18, 2025
Journal
Review of Scientific Instruments
Publisher
AIP Publishing
Citation
R. Kishimori, M. Cufari, E. Z. L. Zhong-Johnson, B. I. Buschmann, A. J. Sinskey, T. M. Johnson, N. Vanderloo, A. DeVault, B. C. Foo, J. Vargas, S. G. Dannhoff, T. E. Evans, J. Kunimune, Y. Lawrence, J. A. Pearcy, B. L. Reichelt, C. W. Wink, R. D. Petrasso, M. Gatu Johnson, J. A. Frenje; Impact of x rays on the sensitivity of CR-39 detectors to 2.4-MeV protons. Rev. Sci. Instrum. 1 July 2025; 96 (7): 073506.
Version
Final published version
Abstract
Solid-state nuclear track detectors, such as CR-39, lose sensitivity when subjected to doses of x rays on the order of 1 Gy in nuclear-fusion relevant experiments. As a result, the formed tracks have, in general, smaller maximum radii and shallower maximum depths. Presented here are experiments using atomic force microscopy to measure the CR-39 sensitivity parameter Vt/Vb, the ratio of track to bulk etch rates, for ∼2.4 MeV protons. The measurements revealed that absorbed x-ray doses of the order of 1 Gy reduced the CR-39 track diameters by a factor of 3 from ∼1200 to ∼400 nm and reduced the track depths by an order of magnitude from ∼550 to ∼50 nm. The corresponding change in the sensitivity parameter was inferred and found to have substantially decreased from ∼1.1 to ≲ 1.01. Doses in excess of 0.5 Gy reduced the track diameter, at an etch time of 2 h, below the 1.0 μm limit typical of optical microscopy methods used when scanning large, i.e., ≳ 25 cm2 , samples of CR-39. The findings suggest that the mechanism of sensitivity loss is driven by x-ray induced cross-linking of the bulk CR-39. The enhanced cross-linking reduces the solubility of the material along charged-particle trajectories compared with that of the bulk material. Representative absorbed doses of between 0.01 and 1 Gy in CR-39 on OMEGA and NIF in typical experimental configurations are then compared with the results.
MIT Department
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Massachusetts Institute of Technology. Department of Biology
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Creative Commons Attribution-Noncommercial
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DOI of Published Version
https://doi.org/10.1063/5.0272809
