Final answer:
For a radiographer positioned behind a control booth, it is crucial for the primary beam to scatter at least two times to reduce radiation exposure effectively. Hence, the correct option for the number of times the primary beam must scatter before reaching the radiographer is B. 2
Step-by-step explanation:
Scattering of the Primary Beam in Radiography
When considering safety precautions in radiography, especially with regard to the primary beam of radiation, it's important to understand the concept of scatter. Scatter can cause radiation to deviate from its original path after interacting with matter, such as the patient's body or surrounding objects. For a radiographer positioned behind a control booth, the primary concern is to ensure that the beam has scattered sufficiently to reduce the intensity of any radiation that might reach them, minimizing their exposure.
The number of times the primary beam must scatter before it can be considered safe for a radiographer behind a control booth varies based on the design and shielding of the control area. However, the general rule of thumb within radiography is that the beam should undergo at least two scatter events before it can be considered significantly less dangerous. Thus, the scattering should happen multiple times to ensure the safety of the radiographer. Therefore, the correct option in the final answer is B. 2.