Determination of the secondary energy from the electron beam with a flattening foil by computer, 2

A computer program written in FORTRAN is described for determining the secondary energy of the electron beam which passed through a flattening foil, using a time-sharing computer service. The fitting of the measured percentage depth dose curve used both an exponential function and a sigmoidal function, as shown in Fig. 1. The practical range is evaluated by the point of intersection P of the line tangent to the fitted sigmoidal curve at the point B (X = b) and the given dose D0, as shown in Fig. 1. Finally, the secondary energy corresponded to the determined practical range can be obtained by the experimental equation (3.5). The secondary energy which was calculated by this method was almost the same as that of the previous paper which used to seventh-degree equation by way of the fitted polynomial. This program can also be estimated the percentage depth dose curve with the specific electron energy, using parameters of two functions which were obtained from functional relationships (1), (2), (5), (6) and (7), as shown in Table 5. The percentage depth dose curve in the high electron energies from 15.81 MeV to 38.52 MeV was possible to estimate the shape of the curve with a high accuracy. However, the shape of the curve in the low electron energies from 2.08 MeV to 10.67 MeV could not produce results with in acceptable statistical accuracy. (author)