93-Np-237

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 192.6 (b) 191.3 (b) 0.993 5.746 (b) 7.581 (b)
elastic 14.47 (b) 16.15 (b) 1.116 2.760 (b) 4.560 (b)
inelastic ( E-thr = 33.34 keV ) 307.2 (mb) 1.526 (b)
(n,2n) ( E-thr = 6.605 MeV ) 522.4 (mb) 2.356 (mb)
(n,3n) ( E-thr = 12.37 MeV ) 6.321 (mb) 1.829 (μb)
fission 20.19 (mb) 19.73 (mb) 0.977 5.368 (b) 2.148 (b) 1.336 (b)
(n,fission) 20.19 (mb) 19.73 (mb) 0.977 4.867 (b) 855.5 (mb) 1.312 (b)
(n,n,fiss) ( E-thr = 2.300 MeV ) 1.038 (b) 24.29 (mb)
(n,2n,fiss) ( E-thr = 9.000 MeV ) 254.1 (mb) 33.84 (μb)
(n,4n) ( E-thr = 19.38 MeV ) 222.5e-18 (b)
(n,3nfiss) ( E-thr = 15.00 MeV ) 3.016 (nb)
capture 178.1 (b) 175.1 (b) 0.983 701.1 (b) 1.273 (mb) 155.2 (mb)
 
νp 2.615 4.618
νd 1.200e-2 8.000e-3

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.