Abstract:The ionization chamber is widely used for the dosimetric measurement on the protection level dose rate in nuclear facilities, radiation therapy, and environmental monitoring. In order to improve the domestic manufacturing level of the ionization chamber, the cavity ionization chamber was studied. The thickness of the ionization chamber wall and the design of the guard electrode were studied by the method of theoretical analysis and Monte Carlo simulation. The designed cavity ionization chamber was tested in the standard X and γ radiation field to evaluate the dosimetry characteristic. The results showed that the leakage current was less than ±5fA, and the work voltage of the cavity ionization chamber was 200~800V. The energy response was tested in the N60~N250 X radiation field and the 137Cs, 60Co γ radiation filed. When the dose rate is normalized to 60Co radiation field, the energy response was better than ±5%. The long-term stability and the angular response of the ionization chamber in half a year was better than 0.5%. At last, it can realize the measurement of dose rate of 3mGy/h~30Gy/h with the relative deviation for the agreed dose rate better than ±5%.
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