99-Es-253

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 193.6 (b) 198.8 (b) 1.027 6.004 (b) 8.243 (b)
elastic 7.134 (b) 7.940 (b) 1.113 2.838 (b) 4.641 (b)
inelastic ( E-thr = 46.58 keV ) 303.2 (mb) 2.424 (b)
(n,2n) ( E-thr = 6.377 MeV ) 489.4 (mb) 4.007 (mb)
(n,3n) ( E-thr = 11.69 MeV ) 132.1 (mb) 16.51 (μb)
fission 2.502 (b) 2.511 (b) 1.004 4.879 (b) 2.239 (b) 1.029 (b)
(n,fission) 2.502 (b) 2.511 (b) 1.004 4.445 (b) 1.291 (b) 1.008 (b)
(n,n,fiss) ( E-thr = 2.300 MeV ) 895.5 (mb) 21.20 (mb)
(n,2n,fiss) ( E-thr = 9.000 MeV ) 51.78 (mb) 8.222 (μb)
(n,4n) ( E-thr = 18.50 MeV ) 3.395e-12 (b)
(n,3nfiss) ( E-thr = 14.00 MeV ) 0.000 (b) 4.772 (nb)
capture 183.9 (b) 188.4 (b) 1.024 3.821 (kb) 922.8 (μb) 143.1 (mb)
 
νp 3.881 7.213
νd 4.107e-3 2.818e-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.