What is the relationship between radiographic intensity and source activity for gamma ray sources?

The relationship between radiographic intensity and source activity for gamma ray sources is characterized by direct proportionality. In practical terms, this means that as the source activity increases, the intensity of the radiation emitted also increases. This can be understood through the concept that a higher activity level of the gamma ray source means that more radioactive atoms are undergoing decay, which leads to a greater number of gamma photons being emitted per unit of time.

This principle is essential in radiographic testing, as it directly affects the quality and penetrative power of the radiographic image. Greater intensity translates into a stronger signal received by the detector, enhancing the visibility of details in the radiograph.

In contrast, if intensity were inversely proportional to activity, that would imply that increasing the source activity would result in a decrease in intensity, which contradicts the fundamental physics of radioactive decay and radiation emission. Saying the intensity is independent of source activity would disregard the inherent properties of gamma radiation production, as the number of emissions is contingent on the activity level. Likewise, the idea that intensity varies with exposure time only would ignore the fact that the activity level directly influences the intensity regardless of how long the exposure is performed. Therefore, the correct answer highlights the intrinsic relationship between the source activity of