Convert From Barn To Square Meter

Barn (designation: b) is an off-system unit of measurement of area, used in nuclear physics to measure the effective cross section of nuclear reactions, as well as the quadrupole moment. 1 barn equals 10⁻²⁸ m² = 10⁻²⁴ cm² = 100 fm² (the approximate size of an atomic nucleus). Multiples and sub-multiples are also determined; of which are used:
megabarn (Mbn, Mb, 10⁻¹⁸ cm²),
kilobarn (kbn, kb, 10⁻²¹ cm²),
millibarn (mbn, mb, 10⁻²⁷ cm²),
microbarn (mkbn, mkb, 10-30 cm²),
nanobarn (nbn, nb, 10−33 cm²),
picobarn (pbn, pb, 10−36 cm²),
femtobarn (fbn, fb, 10⁻³⁹ cm²),
attobarn (abn, ab, 10⁻⁴² cm²),
While the barn never was an SI unit, the SI standards body acknowledged it in the 8th SI Brochure (superseded in 2019) due to its use in particle physics.

A square meter is a unit of measurement of area in the International System of Units, as well as in MTS and MKGSS systems. 1 m² is equal to the area of a square with a side of 1 meter. Instead of a square meter, they sometimes use a unit of centiars (French: centiare, ca), which is not part of the International System of Units (SI). Santiar is a fractional unit of are.