74-W-186

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 38.17 (b) 38.26 (b) 1.002 5.381 (b) 6.848 (b)
elastic 74.24 (mb) 86.43 (mb) 1.164 2.950 (b) 4.423 (b)
inelastic ( E-thr = 105.0 keV ) 398.5 (mb) 2.384 (b)
(n,2n) ( E-thr = 7.230 MeV ) 1.996 (b) 9.586 (mb)
(n,3n) ( E-thr = 13.02 MeV ) 36.06 (mb) 20.85 (μb)
(n,na) 0.000 (b) 0.000 (b) 35.51 (nb) 15.86 (μb) 7.731 (nb)
(n,2na) ( E-thr = 5.624 MeV ) 2.782 (nb) 4.371e-12 (b)
(n,np) ( E-thr = 8.448 MeV ) 1.517 (μb) 6.643 (nb)
(n,nd) ( E-thr = 12.87 MeV ) 10.29e-30 (b) 3.891e-12 (b)
(n,nt) ( E-thr = 12.23 MeV ) 6.841e-24 (b) 1.081e-12 (b)
capture 38.10 (b) 38.17 (b) 1.002 474.1 (b) 771.7 (μb) 30.13 (mb)
(n,p) ( E-thr = 3.136 MeV ) 1.182 (mb) 282.4 (nb)
(n,d) ( E-thr = 6.211 MeV ) 62.24 (μb) 21.95 (nb)
(n,t) ( E-thr = 6.582 MeV ) 1.071 (μb) 1.052 (nb)
(n,He-3) ( E-thr = 7.911 MeV ) 4.492e-21 (b) 54.59e-18 (b)
(n,a) 2.686 (nb) 2.688 (nb) 1.001 1.339 (μb) 377.6 (μb) 153.9 (nb)

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)
 .