Nuclear gauges determine density by counting which particles?

Nuclear gauges used in the inspection of hot mix asphalt (HMA) determine density by counting photons. In this context, the gauge emits gamma radiation, which is a type of high-energy electromagnetic radiation, also referred to as photons. As these photons pass through the material being tested, they are attenuated by the density of the material. The extent of this attenuation is measured and used to calculate the density of the asphalt layer.

Understanding the concept of photons is crucial, as they are the particles that interact with the material, providing the necessary data for density measurements. This method relies on the principle that denser materials will absorb more photons, leading to a measurable decrease in the number of photons detected by the gauge.

Thus, the functionality of nuclear gauges hinges on the detection and analysis of photons, making this the correct choice in understanding how density is evaluated in hot mix asphalt applications.