2.2.2 Data analysis
The test outcomes demonstrate an exponential decay in the target dose across all orientations. As one moves farther from the geometric center of the target, the dose diminishes proportionately.
The specific quantitative analysis process involves: Firstly, computing the distance between the recorded position and the geometric center (origin) of the target based on specific coordinate values, and contrasting the doses. Then identifying equidistant points along the periphery of the target in the water, such as (0,12.5,0), (0,0,32.5), (0,12.5,32.5), (12.5,12.5,0), and (12.5,12.5,32.5) in the rectangular target model, and comparing their respective doses. The comparative results reveal that:
- At equidistant positions from the geometric center of the target, the dose may not consistently remain uniform but can exhibit substantial variations. For instance, in a rectangular target model, the dose at coordinates (0,32.5,0) is 7.57401 × 10-18Gy, while the dose at (0,0,32.5) is 7.03901 × 10-17Gy, indicating a disparity of one order of magnitude.
- For rectangular, hexagonal prism, and cylindrical targets, points situated equidistantly along the periphery in the aquatic medium:
1) With the exception of the point nearest to the surface, the dose at radially perpendicular points exceeds that at axially perpendicular points, as depicted in Fig. 6 (a), (b), and (c). The dose at point b1 surpasses that at point a1, yet the doses at points a2-a10 are marginally higher than those at points b2-b10.
2) Points situated along the geometric diagonal of the target's periphery exhibit lower doses compared to those in the radial and axial directions (depicted in Fig. 6 (a), (b), and (c), where doses at points a1-a10 and b1-b10 surpass those at corresponding points on the curves post b10). The dose at points on the planar diagonal exceeds that at points on the spatial diagonal (as illustrated in Fig. 6, where the dose at points c1-c6 and d1-d6 surpasses the dose at corresponding points e1-e6). Regarding the plane diagonal, the dose at points on the xoy plane diagonal surpasses that at points on the yoz plane diagonal. (For instance, as evidenced in Fig. 6 (a), the dose at points d1-d6 surpasses the corresponding dose at points c1-c6).
3) In the case of spherical targets, the respective points in each direction are essentially equivalent (depicted in Fig. 6 (d)). Conversely, for the cube target, the dose at the three nearest points in the vertical and surface directions significantly exceeds that of the others. Apart from these three points, the dose at corresponding points in each direction is comparable, as illustrated in Fig. 6 (e). The dose at points a1-a3 markedly surpasses that at other points, while the dose at corresponding points on the subsequent three curves is essentially uniform.
4) Upon comparing the data in Fig. 6 (a), (b), (c), (d), and (e), the same inference can be deduced as in Chap. 1: the dose at the two nearest points to the target in cube and spherical targets is greater than the corresponding dose of other targets. However, its decay rate is rapid, and the dose swiftly diminishes to nearly zero.