kBqkg

kBq/kg, or kilobecquerel per kilogram, is a unit of activity concentration used to express the amount of radioactive decay occurring in each kilogram of a material. The becquerel (Bq) denotes one radioactive decay per second, so 1 kBq/kg equals 1000 decays per second per kilogram. The conventional notation is kBq/kg; you may also see the term written as kBqkg, but the slash form is standard in most technical contexts.

This unit is employed across radiological disciplines to quantify contamination or concentration of radionuclides in solids, soils, foods, and biological samples. It provides a concise way to relate the activity of a radionuclide to the mass of the material containing it, independent of sample size. For example, a 0.5 kilogram sample with an activity concentration of 20 kBq/kg has a total activity of 10 kBq.

Measurement and calculation typically involve sampling the material, accurately weighing it, and determining its radioactivity with appropriate detectors. Gamma-ray spectrometry, alpha or beta counters, and liquid scintillation methods are commonly used, depending on the radionuclide. Calibration with standards is essential to convert detector signals into activity values, which are then expressed per unit mass.

It is important to distinguish activity concentration from dose. kBq/kg measures how many decays occur per second per kilogram, not the radiation dose to an organism. Estimating dose requires additional factors such as the radionuclide’s energy, biological uptake, exposure pathways, and exposure time, often using dose coefficients and models.

In regulation and safety, kBq/kg is a standard parameter for reporting contamination levels, guiding monitoring programs and compliance with limits set by national authorities and international bodies.