Читать книгу Essentials of Nuclear Medicine Physics, Instrumentation, and Radiation Biology - Rachel A. Powsner - Страница 54

Range is the distance radiation travels through the absorber. Particles that are lighter, have less charge (such as beta particles), and/or have greater energy travel farther than particles that are heavier, have a greater charge (such as alpha particles), and/or have less energy (Figure 2.10).

In traversing an absorber, an electron loses energy at each interaction with the atoms of the absorber. The energy loss per interaction is variable. Therefore, the total distance traveled by electrons of the same energy can vary by as much as 3% to 4%. This variation in range is called the straggling of the ranges. The heavier alpha particles are not affected to a significant degree and demonstrate very little straggling of range.