The energy response of extended CT ionization chamber was studied by MCNP program and verified by experiment

At present, the effective length of CT ionization chamber commonly used in China is 100mm. When the nominal line is wider than 60mm, the measurement accuracy decreases, and multiple step measurements are required, which is troublesome to operate. In this paper, the energy response of the extended CT ionization chamber with different materials is studied. The MCNP5 program is simulated and verified by the standard radiation field energy response experiment. The experimental results show that the energy response of the collector electrode with 1mm Al core coated with 0.1mm graphite is ±2% in the energy range of CT (100-150) kV, which has good application value.