15-P-31

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 3.352 (b) 3.763 (b) 1.123 1.832 (b) 2.888 (b)
elastic 3.186 (b) 3.597 (b) 1.129 1.160 (b) 2.556 (b)
inelastic ( E-thr = 1.307 MeV ) 53.91 (mb) 298.5 (mb)
(n,2n) ( E-thr = 12.71 MeV ) 16.04 (mb) 2.130 (μb)
(n,na) ( E-thr = 9.984 MeV ) 13.81 (mb) 2.732 (μb)
(n,np) ( E-thr = 7.535 MeV ) 374.1 (mb) 821.8 (μb)
capture 166.2 (mb) 166.3 (mb) 1.001 80.79 (mb) 9.895 (μb) 1.010 (mb)
(n,p) ( E-thr = 732.3 keV ) 91.90 (mb) 30.12 (mb)
(n,a) ( E-thr = 2.007 MeV ) 121.2 (mb) 2.442 (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)
 .