Читать книгу Patty's Industrial Hygiene, Physical and Biological Agents - Группа авторов - Страница 46

Two factors must be considered when designing a shield for betas: the beta energy and the generation of bremsstrahlung. To minimize the bremsstrahlung, choose a beta shield of low atomic number. To stop the betas, choose a shield thickness, using the range–energy curve, Figure 2, which is equal to the range of the beta particle. For example, calculate the thickness of a Lucite shield, whose density is 1.12 g cm⁻³, to stop all the betas from ³²P.

Phosphorus‐32 emits a 1.71‐MeV beta. From Figure 2, one finds the range of a 1.71‐MeV beta to be 800 mg cm⁻² (0.8 g cm⁻²). The required thickness is