Radioactivity quantities

Radioactivity refers to the process by which unstable atomic nuclei lose energy by emitting radiation. The key quantities related to radioactivity include: 1. **Activity (A)**: This is a measure of the rate at which a radioactive substance undergoes decay. Activity is typically expressed in becquerels (Bq), where 1 Bq equals one decay event per second. Another unit of measurement is the curie (Ci), where 1 Ci is equivalent to 3.

Absorbed dose is a measure of the amount of energy absorbed by a material (often biological tissue) from ionizing radiation per unit mass of that material. It is commonly used in the fields of radiation protection, medical physics, and radiobiology to quantify the potential for biological damage following exposure to radiation. The absorbed dose is expressed in grays (Gy), where 1 gray is defined as the absorption of one joule of radiation energy by one kilogram of matter.

Equivalent dose is a measure used in radiation protection to assess the biological effect of ionizing radiation on human tissue. It takes into account the type of radiation and its impact on different types of tissues. The concept is used to quantify the risk associated with exposure to radiation in a way that reflects the potential for harm.

ISO 31-10 is part of the ISO 31 series, which pertains to the international standardization of physical quantities and units. Specifically, ISO 31-10 deals with the topic of "Space and Time." This standard outlines the definitions and recommended units for various measurements related to space (such as length, area, volume) and time, ensuring consistency and clarity in scientific communication across different fields and disciplines.

Specific activity is a term commonly used in biochemistry and molecular biology to refer to the activity of an enzyme, protein, or other biological molecule per unit of mass or concentration. It is typically expressed as units of enzyme activity (such as micromoles of substrate converted per minute) per milligram of protein, or in a similar measurement that allows comparison of the activity relative to the amount of the substance present.