Fig. 1. Structure diagram of the short-range particle source water absorbed dose absolute measurement ionization chamber
Fig. 2. Internal structure of the ionization chamber under Maxwell software
Fig. 3. Electric field diagram with and without guard ring(a) Without protective electrode, (b) With protective electrode
Fig. 4. Variation of electric field change with or without protective electrode
Fig. 5. Electric field diagrams of different guard electrode widths (high voltage electrode remains unchanged)(a) 9 mm, (b) 29 mm, (c) 49 mm, (d) 69 mm, (e) 89 mm, (f) 109 mm
Fig. 6. Electric field changes with different guard electrode widths under invariant high voltage electrodes (color online)
Fig. 7. Electric field diagrams of different guard electrode widths (high voltage electrode keeps the same outer diameter as guard electrode) (a) 9 mm, (b) 29 mm, (c) 49 mm, (d) 69 mm, (e) 89 mm, (f) 109 mm
Fig. 8. Electric field changes with different guard electrode widths while high voltage electrode keeps the same outer diameter as the guard electrode (color online)
Fig. 9. Electric field diagrams of different insulating ring widths (a) 1 mm, (b) 3 mm, (c) 5 mm, (d) 7 mm, (e) 9 mm
Fig. 10. Electric field variation with different insulating ring widths (color online)
Fig. 11. Electric field diagrams with different numbers of grid electrode (a) 0, (b) 1, (c) 3, (d) 7, (e) 15
Fig. 12. Electric field variation with different grid electrode numbers (color online)
Fig. 13. Schematic diagram of different grid shapes
Fig. 14. Electric field diagrams for different grid shapes(a) Rectangle, (b) Round, (c) Triangle
Fig. 15. Electric field variation for different grid shapes (color online)
Fig. 16. Electric field diagrams for different gate widths (a) 2 mm, (b) 5 mm, (c) 10 mm, (d) 20 mm
Fig. 17. Electric field variation for different gate widths (color online)
不变量项目Invariant | 参数 Parameter |
---|
收集极厚度 Collector thickness | 0.01 mm | 高压极厚度 Thickness of high-voltage electrode | 0.01 mm | 两极板间距 Distance between two plates | 200 mm | 收集极半径 Radius of collecting electrode | 50 mm | 高压极半径 Radius of high-voltage electrode | 100 mm | 保护极外径 Outer diameter of protective electrode | 100 mm | 高压极电压 High voltage electrode voltage | 2 kV | 收集极电压 Collector voltage | 0 V |
|
Table 1. Partial simulation parameters