97-Bk-249

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 718.9 (b) 1.079 (kb) 1.501 5.964 (b) 8.084 (b)
elastic 3.935 (b) 4.665 (b) 1.186 2.835 (b) 4.657 (b)
inelastic ( E-thr = 8.816 keV ) 295.2 (mb) 2.296 (b)
(n,2n) ( E-thr = 6.327 MeV ) 343.7 (mb) 2.789 (mb)
(n,3n) ( E-thr = 11.83 MeV ) 31.63 (mb) 4.025 (μb)
fission 3.970 (b) 5.962 (b) 1.502 10.05 (b) 2.454 (b) 1.033 (b)
(n,fission) 3.970 (b) 5.962 (b) 1.502 9.595 (b) 1.252 (b) 1.011 (b)
(n,n,fiss) ( E-thr = 2.300 MeV ) 1.124 (b) 21.70 (mb)
(n,2n,fiss) ( E-thr = 8.500 MeV ) 77.80 (mb) 11.19 (μb)
(n,4n) ( E-thr = 18.41 MeV ) 1.965e-12 (b)
(n,3nfiss) ( E-thr = 14.00 MeV ) 0.000 (b) 1.900 (nb)
capture 711.0 (b) 1.069 (kb) 1.503 1.133 (kb) 902.8 (μb) 94.05 (mb)
 
νp 3.410 6.406
νd 8.900e-3 6.100e-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.