What two types of ionizing radiation are commonly used for density and moisture measurement?

The correct answer points to the use of neutron and gamma radiation for density and moisture measurement due to their distinct properties that make them suitable for this application.

Neutron radiation is particularly effective for measuring moisture because neutrons interact with hydrogen nuclei, which are abundant in water. When neutrons are emitted from a source and collide with hydrogen atoms in moisture, they result in scattering that can be quantified to determine moisture content. This interaction is critical in various fields, especially in soil and construction applications where moisture levels are essential.

Gamma radiation, on the other hand, is used for density measurements because it penetrates materials more deeply than other forms of radiation and can be absorbed differently based on the density of the material it encounters. The attenuation of gamma rays as they pass through materials allows for an accurate assessment of density, which is essential in various industries, including manufacturing and civil engineering.

Together, neutron and gamma radiation provide a reliable means of assessing both moisture and density, which is why they are commonly utilized in nuclear gauges for these measurements.