Unit 50: Linear Attenuation
Practice Problems
Note: problem difficulty is ranked using a star system.
(*) One-star problems are fundamental to the unit, and can be done relatively quickly. Use these problems to introduce yourself to the material.
(**) Two-star problems are more difficult, and require an understanding of one or two key concepts. Use these problems to test your understanding of the material.
(***) Three-star problems are the most difficult, and require some creative thinking in addition to a deep familiarity with multiple key concepts. Use these problems to challenge yourself; if you can complete one of these, you’re on your way to mastering the material.
*Q50.1) Convert an attenuation coefficient of 0.35cm⁻¹ to the following quantities:
a) Mean free path aka penetration depth
b) Half-value layer
**Q50.2) A beam of 2 MeV β-particles has a half-value layer in lead of 2.5cm. What thickness of lead is required to block 90% of the beam?
***Q50.3) A beam of 4.2 MeV β-particles is incident on a 0.2cm-thick layer of gold (density 19 300 kg/m³). What percentage of the beam is attenuated by the gold?