Note: Voltage and intensity dependence of the saturation curves of free-air ionization chambers irradiated with chopped synchrotron radiation beams.

Current saturation characteristics of free-air ionization chambers with electrode gaps of 4.2 and 8.4 mm were investigated using pulsed photon beam obtained by periodically interrupting synchrotron radiation beams with a chopper. Pulsed photon beams of 10 and 15 keV with pulse duration of 2.5 μs and a frequency of 230 Hz were produced by chopping the beam. The measured recombination rate was found to be proportional to the intensity and inversely proportional to the applied voltage.