The well-known CR-39, or poly allyl diglycol carbonate (PADC), has been widely used for personal neutron dosimetry for over 40 years. For providers of individual monitoring service (IMS) of neutron dose, it is necessary to establish an automatic reading system for CR-39 detectors in two aspects: to quickly measure a large number of detectors returned from users, and to ensure precision and accuracy that meet the requirements of the ISO/IEC 17025 standard. In this study, a novel high-speed and precise system composed of three parts was developed: (I) image acquisition of etched tracks on CR-39 detectors using an optical microscope with an autofocusing module and a high-speed scanning stage, (II) image processing of the tracks using an integrated software for automatic pit-counting on CR-39 (ISAP-39), including dedicated image processing in two steps, judging exposure in screening mode and evaluating neutron dose in precise reading mode, and (III) data reviewing by dosimetry experts. In the performance evaluation of the system, the following results were confirmed: high-speed scanning with 30 s per detector, high image-processing performance with 0 % false positive detection rate for neutron-induced tracks in screening and over 83 % true positive rate in precise reading, capability to describe differences in track features due to different neutron sources, and capability for precise dose measurements, including coefficient of variation, linearity, and track counting uncertainties. Moreover, in the operational study, the system was confirmed to be valid in terms of the screening function, threshold setting, pass rate stability in screening, and validity of precise reading and data reviewing. Consequently, the CR-39 reading system was proven to have sufficient performance in terms of reading speed and measurement precision.
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