Well-Type Ionization Chamber for ¹⁹²Ir Source Calibration

A welltype ionization chamber was developed for calibrating ¹⁹²Ir sources with high dose-rate. The chamber has a sensitive volume of about 271 cm³ with 99.96% efficiency of ions collection at 300 V chamber bias, and the variation of source move sensitivity is less than ±0.3% for source position. The chamber has a response of 0.230 nA/GBq with uncertainty of 1.5%. Comparing with a chamber calibrated by IAEA, the result is in agreement with each other.