A gas ionization chamber is a type of gas detector used for detecting ionizing radiation. High-energy rays ionize the gas, and the gas ionization chamber collects the electrons and positive ions generated by ionization to form a current. Since the current is proportional to the intensity of the radiation, measuring the current provides the intensity of the ionizing radiation. Additionally, the ionization chamber has a photoelectric detector that can be switched into the optical path, which can be used to measure the wavelength of the radiation by utilizing the absorption spectrum of the gas.