93-Np-239

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 56.13 (b) 57.63 (b) 1.027 5.906 (b) 7.944 (b)
elastic 11.02 (b) 12.45 (b) 1.129 2.823 (b) 4.646 (b)
inelastic ( E-thr = 31.26 keV ) 351.9 (mb) 2.580 (b)
(n,2n) ( E-thr = 6.241 MeV ) 1.102 (b) 9.275 (mb)
(n,3n) ( E-thr = 11.75 MeV ) 188.8 (mb) 24.64 (μb)
fission 28.01 (mb) 28.06 (mb) 1.002 2.247 (b) 1.435 (b) 590.4 (mb)
(n,fission) 28.01 (mb) 28.06 (mb) 1.002 1.800 (b) 519.5 (mb) 568.8 (mb)
(n,n,fiss) ( E-thr = 2.300 MeV ) 786.9 (mb) 21.77 (mb)
(n,2n,fiss) ( E-thr = 9.500 MeV ) 129.2 (mb) 20.41 (μb)
(n,4n) ( E-thr = 18.36 MeV ) 40.90e-12 (b)
(n,3nfiss) ( E-thr = 14.00 MeV ) 0.000 (b) 17.93 (nb)
capture 45.02 (b) 45.03 (b) 1.000 931.8 (b) 1.257 (mb) 116.7 (mb)
 
νp 2.699 4.471
νd 2.186e-2 1.494e-2

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)
 .


νp, νd : numbers of prompt and delayed neutrons per fission.