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Summary

Yongzhen Xia, Runjie Di, Yongji Xie — Health Physics · Spent-fuel dissolution produces multi-nuclide, high-activity aerosols. Gross α/β CAMs are prone to interference and slow response, limiting timely dose assessment and alarms. We developed an integrated multiparameter synchronous detection system to simultaneously measure activity concentration, spectra, and particle size. The instrument integrates sampling and optical sizing (0.1–10 μm) with a silicon barrier (α), thin-window proportional (β), and 2 × 2 NaI (Tl) (γ) detectors. Signals are digitized (14-bit/100 MS s -1 ) for pulse-shape discrimination and 8,192-channel spectrometry. Performance followed ISO 11929/Currie. Standard sources and mixed-nuclide aerosols were used for calibration, linearity, response, and misclassification tests; stability was assessed over 720 h (50 L min -1 , 60 s integration). Detection efficiencies were 26.3% ( 241 Am α), 42.5% ( 90 Sr/ 90 Y β), and 31.2% (