Convert Roentgens to Femtocoulombs per kilogram
Convert Roentgens (R) to Femtocoulombs per kilogram (fC/kg) instantly and accurately.
Conversion Formula
fC/kg = R × 258000000000
About Roentgens
The roentgen (R) equals exactly 2.58 × 10⁻⁴ C/kg, the historical unit of X-ray and gamma-ray exposure defined in 1928 (ICRU) and redefined exactly in 1962. Still widely used in the US: field survey instruments read in R/h; NRC and EPA regulations cite R and mR; the Chernobyl accounts famously reported readings in R/h. 1 R = 2.58 × 10⁻⁴ C/kg.
About Femtocoulombs per kilogram
The femtocoulomb per kilogram (fC/kg) equals 10⁻¹⁵ C/kg. Used in computational dosimetry to characterise the ionisation yield from single low-energy photon interactions in nanogram air volumes; ultra-sensitive free-air ionisation chamber simulations in microdosimetry research report air-ionisation at the fC/kg level. 1 fC/kg = 10⁻¹⁵ C/kg = 10⁻³ pC/kg.
Quick Reference Table
| Roentgens (R) | Femtocoulombs per kilogram (fC/kg) |
|---|---|
| 1 R | 2.58 × 1011 fC/kg |
| 2 R | 5.16 × 1011 fC/kg |
| 5 R | 1.29 × 1012 fC/kg |
| 10 R | 2.58 × 1012 fC/kg |
| 25 R | 6.45 × 1012 fC/kg |
| 50 R | 1.29 × 1013 fC/kg |
| 100 R | 2.58 × 1013 fC/kg |