The roentgen (or röntgen) was previously used as a unit to measure radiation exposure. It was defined as the quantity of x-rays that produces 2.580 × 10-4 coulombs of charge collected per unit mass (kilograms) of air at standard temperature and pressure (STP): 1 R = 0.000258 C/kg air.

History and etymology

Named after Wilhelm Conrad Roentgen who first detected x-rays in 1895. 

Share article

Article information

rID: 18983
Section: Physics
Tags: stub, refs
Synonyms or Alternate Spellings:
  • Röntgen
  • Röntgens
  • Roentgens

Support Radiopaedia and see fewer ads

Updating… Please wait.

Alert accept

Error Unable to process the form. Check for errors and try again.

Alert accept Thank you for updating your details.