Development of In Situ Selective Beta-Ray Distribution Detection Technology Based on Gamma-Ray Sensitivity Difference

An in situ detection method for beta-ray distribution was developed. The method uses the gamma-ray sensitivity difference between two scintillators: a cadmium-tungstate (CdWO
₄
) scintillator and a plastic scintillator. The gamma-ray sensitivity ratios for several gamma-ray sources such as
¹³⁷
Cs,
⁶⁰
Co,
²²
Na, and
⁵⁴
Mn were experimentally characterized. The sensitivity ratio for
¹³⁷
Cs between the CdWO
₄
and plastic scintillators was 8 ± 0.32, while the sensitivity ratio for beta rays from
⁹⁰
Sr was 1.03 ± 0.006. The beta-ray contributions to the total counts can be evaluated using this characteristic. A combined beta-ray and gamma-ray source was prepared, and its beta-ray distribution was successfully obtained using the proposed method.