本实验室研制了BPS型组织等效球形空腔电离室,并对其基本性能进行了测定。该室采用三电极结构并设有TE气体进出口。当工作电压选在250V和500V时,饱和修正因子分别为1.003和1.0007。射线入射角度在120°以内时,响应变化不大于0.5％。对柄效应和光子能量响应进行了研究。测量结果表明,TE气体成分的变化会引起较明显的测量误差。 The laboratory developed a BPS equivalent spherical cavity ionization chamber, and its basic properties were determined. The chamber uses a three-electrode structure with TE gas inlet and outlet. When the operating voltage is selected at 250V and 500V, the saturation correction factors were 1.003 and 1.0007 respectively. Radiation incident angle of 120 ° or less, the response change of not more than 0.5%. The effects of the handle and photon energy were studied. The measurement results show that the change of TE gas composition will cause more obvious measurement error.