91-Pa-229

Reaction 0.0253-eV Maxwellian
Average
g-factor Resonance
Integral
14-MeV Fiss. Spec.
Average
total 413.0 (b) 424.3 (b) 1.027 5.811 (b) 7.512 (b)
elastic 11.83 (b) 13.37 (b) 1.130 2.804 (b) 4.340 (b)
inelastic ( E-thr = 160.7 eV ) 319.6 (mb) 1.037 (b)
(n,2n) ( E-thr = 7.129 MeV ) 925.1 (mb) 1.456 (mb)
(n,3n) ( E-thr = 13.13 MeV ) 1.640 (mb) 1.921 (μb)
fission 1.000 (b) 1.071 (b) 1.071 20.46 (b) 1.760 (b) 1.963 (b)
(n,fission) 1.000 (b) 1.071 (b) 1.071 20.03 (b) 850.3 (mb) 1.946 (b)
(n,n,fiss) ( E-thr = 2.000 MeV ) 902.6 (mb) 17.67 (mb)
(n,2n,fiss) ( E-thr = 10.50 MeV ) 6.738 (mb) 6.621 (μb)
(n,3nfiss) ( E-thr = 15.50 MeV ) 56.32e-12 (b)
capture 399.9 (b) 408.5 (b) 1.021 757.3 (b) 1.159 (mb) 168.1 (mb)
 
νp 2.240 3.556
νd 5.153e-3 3.569e-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.