Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Development of a device to improve the precision of water surface identification for MeV electron beam dosimetry

  • F. Okky Agassy (University of Science and Technology (UST)) ;
  • Jong In Park (Korea Research Institute of Standards and Science (KRISS)) ;
  • In Jung Kim (University of Science and Technology (UST))
  • Received : 2023.06.22
  • Accepted : 2023.11.27
  • Published : 2024.04.25
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Abstract

The study aimed to develop a laser-based distance meter (LDM) to improve water surface identification for clinical MeV electron beam dosimetry, as inaccurate water surface determination can lead to imprecise positioning of ionization chambers (ICs). The LDM consisted of a laser ranging sensor, a signal processing microcontroller, and a tablet PC for data acquisition. I50 (the water depth at which ionization current drops to 50 % of its maximum) measurements of electron beams were performed using six different types of ICs and compared to other water surface identification methods. The LDM demonstrated reproducible I50 measurements with a level of 0.01 cm for all six ICs. The uncertainty of water depth was evaluated at 0.008 cm with the LDM. The LDM also exposed discrepancies between I50 measurements using different ICs, which was partially reduced by applying an optimum shift of IC's point of measurement (POM) or effective point of measurement (EPOM). However, residual discrepancies due to the energy dependency of the cylindrical chamber's EPOM caused remained. The LDM offers straightforward and efficient means for precision water surface identification, minimizing reliance on individual operator skills.

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Acknowledgement

The research was supported by the Korea Research Institute of Standards and Science (KRISS) (Grant number: GP2022-0005-13) and the National Research Council of Science & Technology (NST) grant by the Korea government (MSIT) (No. CAP22041-100).

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