Millibarn
Definition and meaning of Millibarn in chemistry.
Millibarn is a unit of area equal to one-thousandth of a barn (10^-27 cm^2 or 10^-31 m^2), used to measure the effective cross-section of nuclear reactions and particle interactions.
In more detail
The barn, named humorously for being much smaller than a barn building, is the standard unit for nuclear cross-sections in chemistry and physics. The millibarn (10^-3 barns) expresses the effective area a nucleus presents to an incoming particle, determining the probability of nuclear interaction. Millibarns are especially important in neutron activation analysis and laboratory nuclear experiments where cross-sections fall within this convenient measurement range. Accurate cross-section values in millibarns are essential for quantifying reaction rates and designing sensitive analytical and experimental procedures.
Key facts
| Abbreviation | mb |
|---|---|
| Equivalent to | 10^-27 cm^2 or 10^-31 m^2 |
| Relationship to barn | One millibarn equals 10^-3 barns |
| Field | Physical Chemistry |
In neutron activation analysis, reactions with thermal neutron cross-sections of 1 to 1000 millibarns are frequently employed because they provide optimal sensitivity for detecting trace elements without requiring impractically long irradiation times.
Frequently asked questions
What does cross-section mean in nuclear chemistry?
Cross-section is the effective area that a nucleus or particle presents to an incoming projectile, directly related to the probability that a nuclear interaction will occur.
Why are millibarns used instead of larger units like barns?
Many nuclear reactions have cross-sections in the millibarn to kilobarn range, making millibarns a practical unit that provides convenient numerical values without excessive scientific notation.