Exposure and shielding from external radiation
This chapter opens with specific gamma ray constants and the mean attenuation coefficients for selected radionuclides important in radiation assessment and protection. The bulk of the material in this chapter deals with shielding information and practical values for the transmission of radiation through different materials from common radiation sources and x-ray machines. Parameters are given for shielding calculations (half-value layers for gamma and x-ray radiations at varying energies for various materials and buildup factors), as well as ranges of electrons, alpha particles and protons in various materials. Attenuation through lead, concrete and other materials is illustrated in tables and graphs for x-ray energies in the diagnostic and therapeutic range. Shielding requirements for primary and secondary barriers for three phase x-ray generators and for mammography units are presented. Similar tables are given for {sup 60}Co and {sup 137}Cs. Also included are percentage backscatter of x-rays from patients and calculated exposure rates from patients containing selected radionuclides at various distances. The chapter concludes with information on shielding for accelerator facilities, that is: broad beam transmission through lead, concrete and steel, and TVLs for bremsstrahlung.
- OSTI ID:
- 142121
- Country of Publication:
- United States
- Language:
- English
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