Convert rad [rd] to joule/kilogram [J/kg] Online | Free radiation-absorbed-dose Converter

Rad [rd]: A Legacy Unit of Absorbed Radiation Dose

The rad (short for radiation absorbed dose) is a legacy unit used to measure the amount of ionizing radiation energy absorbed per unit mass of material. It was widely used before the adoption of the gray (Gy) in the International System of Units (SI).

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  1 rad = 0.01 gray (Gy)

  
  
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  This means that 1 rad corresponds to the absorption of 0.01 joules of radiation energy per kilogram of matter.

  
  

The rad was commonly used in medical, industrial, and scientific settings to quantify radiation doses. Although now largely replaced by the gray for consistency and international standardization, the rad is still sometimes referenced in older research, medical records, and certain fields.

The rad and its subunits (like the millirad) helped establish the groundwork for understanding radiation exposure and effects before the transition to the more precise and universally accepted gray unit.

Joule per Kilogram [J/kg]: The Basis of the Gray (Gy)

The joule per kilogram (J/kg) is the SI unit for absorbed radiation dose, directly defining the gray (Gy). It measures the amount of energy—joules—absorbed by each kilogram of a substance (usually tissue or material) when exposed to ionizing radiation.

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  1 gray (Gy) = 1 joule per kilogram (J/kg).

  
  

This unit is fundamental in radiation physics, radiology, and radiation protection because it quantifies how much radiation energy is deposited in matter, which is critical for understanding biological effects, radiation damage, and safety limits.

Since it measures energy absorbed per mass, J/kg is widely used to:

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  Assess radiation doses in medical diagnostics and therapy.

  
  
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  Monitor exposure in nuclear industry and radiation protection.

  
  
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  Conduct research in radiation biology and physics.

  
  

The joule per kilogram is essential for ensuring consistent, standardized measurements of radiation doses across scientific, medical, and industrial fields.