90-Th-231

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
(n,total) 1.683 (kb) 1.689 (kb) 1.003 5.859 (b) 7.656 (b)
(n,elastic) 12.03 (b) 13.58 (b) 1.129 2.828 (b) 4.522 (b)
(n,inelastic) ( E-thr = 42.14 keV ) 348.7 (mb) 2.729 (b)
(n,2n) ( E-thr = 5.140 MeV ) 1.685 (b) 42.73 (mb)
(n,3n) ( E-thr = 11.96 MeV ) 335.8 (mb) 50.85 (μb)
(n,fission) 40.01 (b) 39.99 (b) 0.999 281.7 (b) 657.9 (mb) 199.2 (mb)
(n,f) 40.01 (b) 39.99 (b) 0.999 281.6 (b) 127.4 (mb) 195.3 (mb)
(n,nf) ( E-thr = 2.000 MeV ) 228.3 (mb) 3.845 (mb)
(n,2nf) ( E-thr = 7.000 MeV ) 302.3 (mb) 47.68 (μb)
(n,4n) ( E-thr = 17.24 MeV ) 15.78 (nb)
(n,3nf) ( E-thr = 14.50 MeV ) 1.938 (nb)
(n,γ) 1.631 (kb) 1.633 (kb) 1.001 725.1 (b) 1.215 (mb) 162.1 (mb)

These cross sections are calculated from JENDL-4.0 at 300K.
The background color of each cell noted a cross section means the order of the cross-section value.
The unit of cross section, (b), means barns, and SI prefixes are used as following.
(kb) → 103(b),   (mb) → 10−3(b),  (μb) → 10−6(b),  (nb) → 10−9(b).

Maxwellian Average :
σmacs(T) =
2
 
 
π
EU
 
EL
σ(E,T) ⋅ E ⋅ exp (
E
  
kBT
) dE
 
EU
 
EL
E ⋅ exp (
E
  
kBT
) dE
,
where T denotes the temperature, and kB the Boltzmann constant. The upper and lower limits of integration, EL and EU are set to 10−5 eV and 10 eV, respectively.
Resonance Integral :
σri(T) =
EU
 
EL
σ(E,T) ⋅
1
 
E
dE ,
with  EL = 0.5 eV  and  EU = 10 MeV.
U-235 Thermal Fission-Neutron Spectrum Average (Fiss. Spec. Average) :
σfacs(T) =
EU
 
EL
σ(E,T) ⋅
 
4
 
πa3b
⋅ exp (
ab E
     
4 a
) ⋅ sinh
 
bE
dE
 
EU
 
EL
 
4
 
πa3b
⋅ exp (
ab E
     
4 a
) ⋅ sinh
 
bE
dE
,
with  EL = 10−5 eV  and  EU = 20 MeV. The parameters a and b are 0.988 MeV and 2.249 MeV−1, respectively.
Westcott g-factor :
g(T) =
σmacs(T)
 
σ(0.0253 eV,T)
 .