Convert femtogray [fGy] to joule/centigram [J/cg] Online | Free radiation-absorbed-dose Converter

Femtogray [fGy]: A Tiny Unit of Radiation Dose


The femtogray (fGy) is a unit of absorbed radiation dose equal to 10⁻¹⁵ grays (Gy). The gray (Gy) is the standard SI unit used to measure the amount of ionizing radiation energy absorbed per kilogram of matter. One femtogray, therefore, represents a quadrillionth (0.000000000000001) of a gray. This unit is extremely small and is primarily used in theoretical research, nanodosimetry, or highly sensitive radiation studies where even the smallest levels of energy absorption can have measurable effects on microscopic or molecular systems. While real-world applications like medical imaging or radiation therapy use much larger units such as milligray (mGy) or gray (Gy), the femtogray can help researchers simulate or analyze interactions of radiation with DNA, proteins, or other cellular components. Although it is impractical for most everyday uses due to its tiny scale, the femtogray plays a valuable role in scientific fields requiring ultra-precise radiation dose measurements. It demonstrates how finely scientists can scale radiation measurements to better understand the effects of energy on matter at the smallest biological or atomic levels.


Joule per Centigram [J/cg]: A Unit of Energy per Mass


The joule per centigram (J/cg) expresses the amount of energy absorbed or delivered per unit mass, specifically joules of energy per centigram (1 centigram = 0.01 grams). This unit represents energy density on a small mass scale.


To relate it to standard radiation dose units: since 1 gray (Gy) equals 1 joule per kilogram (J/kg), and 1 centigram equals 10⁻⁵ kilograms, then



  • 1 J/cg = 1 joule per 0.00001 kg = 100,000 J/kg = 100,000 Gy.



This means that 1 J/cg corresponds to a very high absorbed radiation dose, much greater than typical doses used in medicine or radiation safety.


J/cg could be useful in very specialized fields where energy deposition is considered over tiny masses, such as microdosimetry, materials science, or radiation effects at microscopic scales.


In general, joule per centigram is a high-precision measure for energy density per small mass, but it’s not commonly used in everyday radiation measurement, where grays or their subunits are preferred.



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