This web page allows you to convert the different radioactivity units and answers the following questions in particular: What is radioactivity and how is it measured? What were the most common units used to measure radioactivity before 1900 and what replaced them in 1975? What are some interesting facts about radioactivity measurement units? What are some examples of reference or record values in different radioactivity units? How can different units of radioactivity be converted?
Radioactivity is a physical phenomenon found in certain materials, in which spontaneous emission of charged particles or electromagnetic waves occurs, resulting in the object’s disintegration. Radioactivity has been studied for several centuries and is used for different types of measurements. Common units used to measure radioactivity are measured in the activity of a quantity of radioactive material and this is expressed as the number of disintegrations taking place per unit time, usually in one second ( counted per second, cps).
The history of radioactivity units is partially tied with the development of modern science and technology, as well as the discovery of new radioactive materials. Before 1900, the most common unit used to measure radioactivity was the curie (Ci). The curie is defined as the quantity of radioactive material containing as many particles undergoing nuclear transitions as 0.0003 Ci of uranium (U). However, in 1975 the International System of Units replaced the curie with the becquerel (Bq). The becquerel is defined as the activity of a quantity of radioactive material in which one nucleus disintegrates per second. Since then, two other units of measurement, the Gray (Gy) and Rad (Rad), have established themselves as the default units for measuring the effect of radiation on intact tissues and for expressing the absorbed dose, respectively.
The most interesting fact about radioactivity measurement units is that one curie is equivalent to 27 billion becquerels (3.7×1010 Bq). Another fact is that a single Gray is equivalent to 100 rads, and that any exposure to over 10 mSv in a single year is considered to be dangerous. Another interesting fact is that the Gray is primarily used in dosimetry, while the Rad is typically used to describe the exposure rate of an irradiated material.
Here is a list of reference and record values in the different units of radioactivity:
To convert different units of radioactivity all you need is a converter calculator. Most of these converters use the common radioactivity measurement units as defined within the International System of Units, such as the becquerel (Bq), curie (Ci), rad (rad), gray (Gy) and lumen (lm). There are also calculators available online that can automatically convert between different radioactivity units. For example, the Becquerel calculator converts the activity of a radioactive material from curies to becquerels and vice versa. The Gray and Rad calculator allows you to convert the Gray to Rad in both directions. The Lumen calculator is used to convert lumens from lux and foot candles or vice versa.