Convert Barns to Circular Mils
Convert Barns (b) to Circular Mils (cmil) instantly and accurately.
Conversion Formula
cmil = b × 1.973525241e-19
About Barns
A barn (b) is a unit of area used in nuclear and particle physics to measure effective cross-sections of atomic nuclei and particle interaction probabilities. Equal to 10⁻²⁸ m² (10⁻²⁴ cm²), it was humorously named during the Manhattan Project - physicists joked that uranium nuclei were 'as big as a barn' at the subatomic scale. Particle physics experiments at accelerators like CERN report cross-sections in millibarns (mb), microbarns (μb), nanobarns (nb), and femtobarns (fb).
About Circular Mils
A circular mil (cmil) is a unit used in electrical engineering to specify the cross-sectional area of round wires and cables. Equal to the area of a circle with a diameter of exactly one thou (one thousandth of an inch) - approximately 5.067 × 10⁻¹⁰ m² - it simplifies wire calculations: the cross-sectional area in cmil equals the wire diameter in mils, squared. US electrical codes (NEC/NEMA) specify conductor sizes in circular mils, and large cables are rated in thousands of circular mils (kcmil or MCM). A 12 AWG wire, common in US household wiring, has a cross-section of 6,530 cmil.
Quick Reference Table
| Barns (b) | Circular Mils (cmil) |
|---|---|
| 1 b | 1.974 × 10-19 cmil |
| 2 b | 3.947 × 10-19 cmil |
| 5 b | 9.868 × 10-19 cmil |
| 10 b | 1.974 × 10-18 cmil |
| 25 b | 4.934 × 10-18 cmil |
| 50 b | 9.868 × 10-18 cmil |
| 100 b | 1.974 × 10-17 cmil |