Abstract
The energy fluence of air irradiated with 300 keV electron beam (EB) was calculated using a Monte Garbo electron transport code named as EGS4-SPG code, which simulates 3-dimensional traverse of electrons in media. For evaluation of the effectiveness of the calculation, the results were compared with the energy fluenece rates measured by a calorimeter for the distances of 4.5-16.2 cm from the irradiation window of an irradiation vessel. As a result, the tendency of the calculated results as a function of depth in air agreed with the experimental results within the errors of ±1.3%. The calculated results also show that the overlap of energy fluenece rate distributions in air below each filament is sufficient at the depth deeper than 4.5 cm to provide the uniform energy fluence rate independently of the position of the calorimeter. In general, the measurement of an energy fluence rate distribution in air is difficult for electrons with their kinetic energy lower than 300 keV. Once the agreement between the calculation and the measurement is confirmed, even at one position, one can estimate an energy fluence rate distribution under similar irradiation geometry by only calculation.
