4pi gamma well-shaped ionization chamber with extremely low energy and high lower limit air pressure

The invention belongs to the field of radiation protection, and provides an extremely low energy lower limit high air pressure 4pi gamma well-shaped ionization chamber for radioactive activity measurement, which comprises a detector measurement unit, the detector measurement unit comprises a high voltage electrode and a collector, and high voltage is applied between the high voltage electrode and the collector to form an electric field. Radiation is converted into current signals on the collector, the collector penetrates through the insulator to lead out the current signals and transmits the current signals to the pre-amplification circuit board, the high-voltage electrode is composed of two coaxial cylindrical cylinders, an upper circular ring-shaped connecting part and a lower circular ring-shaped connecting part, and the collector is a coaxial cylinder and is embedded in the middle of the cylinder of the high-voltage electrode. High-pressure working gas is filled between the high-pressure electrode and th