Definition of cross sections 1 - Moodle

Definition of cross sections 7In a similar way, we may define cross sections for reactions involving the absorption of theincident neutron. A representation of this hierarchy is given in figure.Nuclear reactions in reactor physics are often represented with the following notation:(n,n):(n,n’):(n,γ):elastic scattering,inelastic scattering,the radiative capture cross section σ γ(n,f): the fission cross section σ f ,(n,α), (n,p):(n,2n):transmutation cross sections σ α (an α particle is emitted)or σ p (a proton is emitted)n-2n reaction, etc.All these reactions, with the exception of the potential scattering, involve the formation of acompound nucleus and are characterized by cross sections that may exhibit high variationwith neutron energy. This phenomena will be studied in the next section.The total cross section is the sum of all existing cross sections.ENE6101: Week 4 Cross sections – 9/37