Radiation Dose Converter

Gray, sievert, rad, and rem with Q=1 (x-rays/gamma); not for mixed radiation fields.

Four units, but two genuinely different quantities. Gray and rad measure absorbed dose, the plain energy deposited per kilogram of tissue, while sievert and rem measure equivalent dose, that same energy weighted by how much biological harm the particular radiation causes. Within each pair the relationship is a clean hundred to one, the SI unit against its older CGS partner, so the default of one milligray returns one millisievert alongside 0.1 rad and 0.1 rem. What lets the gray and sievert columns show the identical figure is an assumption the engine prints in its own note: a quality factor of one. That is right for X-rays, gamma rays and beta particles, which covers virtually every medical or dental exposure a patient will meet. It is wrong for alpha particles, which carry a weighting factor of 20, and for neutrons, where the factor ranges from roughly 5 to 20 with energy, so in a mixed field the sievert reading here would understate the biological dose severely. Several neighbouring concepts are simply absent. There is no dose rate, since no time is collected and a survey meter reports microsieverts per hour rather than a total. There is no activity, so becquerels and curies — which describe how fast a source is decaying, not what reached a person — have no place here, nor does exposure in roentgens, nor any term for distance or shielding. For a sense of scale, natural background exposure runs around 2 to 3 millisieverts a year.