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4
.
Source spacing is a function of thickness
- Single plane
Ratios of source spacing to target thickness and
source length to target length
- Spacing = 2 x target thickness (2 sources)
- Spacing = 1.67 x target thickness (3 or more sources)
- Double plane
- Square spacing = 0.62 to 0.64 x target thickness
- Triangles spacing = 0.75 to 0.79 x target thickness
5. Source length is a function of target length
- radio active Length = 1.33 to 1.54 x target length
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