The distribution of ionization along a beam of ?-radiation and the determination of radiation dose with normal ionization chambers

Physical aspects of irradiation: recommendations of the International Commission on Radiological Units and Measurements (ICRU) report 10B 1962

“…There¬ fore, the air absorption correction should be less than that for the distance between the center of the collecting region and the diaphragm. This decrease has been computed to be 0.8 percent for cobalt-60 gamma rays and 0.4 percent for cesium-137 gamma rays (Aglintsev and Ostromukhova, 1959).…”

Standardization of cesium-137 gamma-ray sources in terms of exposure units (Roentgens)

“…An estimate of the reduction required in the absorption correction has been provided by Wyckoff [3]. From measurements of electronic equilibrium requirements for 60CO and 137CS gamma rays in a parallel-plate pressure chamber, and the calculations of Roesch [4] and Aglintsev [5] , he computed the required reduction in the absorption correction to be 0.2 percent for 137 CS gamma rays and carbon·walled cavity chambers. The saturation correction for the exposure rates encountered in these measurements is 0.2 percent and the correction for scatter from the supporting stem and shank of the chamber is 0.1 percent.…”