94-Pu-244 JAEA+ EVAL-FEB10 O.Iwamoto, T.Nakagawa, +
DIST-MAY10 20100318
----JENDL-4.0 MATERIAL 9452
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
06-12 Fission cross section was revised with GMA code.
07-05 Data were calculated with CCONE code.
Data were compiled as JENDL/AC-2008/1/.
10-02 Data of prompt gamma rays due to fission were given.
10-03 Covariance data were given.
MF= 1 General information
MT=452 Number of Neutrons per fission
Sum of MT=455 and 456
MT=455 Delayed neutrons
(same as JENDL-3.3)
Determined from the systematics of Manero and Konshin/2/.
MT=456 Number of prompt neutrons per fission
(same as JENDL-3.3)
Determined from the data for Pu-240 and Pu242.
MF= 2 Resonance parameters
MT=151
Resolved resonance parameters (below 290 eV)
(almost the same as JENDL-3.3)
Recommendation of Mughabghab/3/ was adopted. Mughabghab
adopted experimental data of Auchampaugh et al./4/
The average capture width of 20 meV was assumed.
Fission widths were determined so as to reproduce integrated
measured fission cross sections around each resonance peak.
The scattering radius of 9.33 fm adopted was obtained from an
optical model calculation.
For the present file, a neutron width of a negative resonance
was adjusted to the thermal capture cross section of 1.71b,
which were determined from the data of Fields et al./5/,
Butler et al./6/ and Schuman/7/.
Unresolved resonance parameters (290 eV - 100 keV)
Unresolved resonance parameters were determined with ASREP
code/8/ so as to reproduce the total and capture cross
sections calculated with CCONE code/9/, and average fission
cross section determined with GMA code/10/. The parameters are
used only for self-shielding calculations.
Thermal cross sections and resonance integrals (at 300K)
-------------------------------------------------------
0.0253 eV reson. integ.(*)
(barns) (barns)
-------------------------------------------------------
total 12.099
elastic 10.387
fission 0.0017 3.69
capture 1.710 47.8
-------------------------------------------------------
(*) In the energy range from 0.5 eV to 10 MeV.
MF= 3 Neutron cross sections
Cross sections above the resolved resonance region except for
the elastic scattering (MT=2) and fission cross sections (MT=18,
19, 20, 21, 38) were calculated with CCONE code/9/.
MT= 1 Total cross section
The cross section was calculated with CC OMP of Soukhovitskii
et al./11/.
MT= 2 Elastic scattering cross section
Calculated as total - non-elastic scattering cross sections.
MT=18 Fission cross section
The following experimental data were analyzed in the energy
range from 290 eV to 20 MeV with the GMA code /10/:
Authors Energy range Data points Reference
Auchampaugh+ 280 eV - 400 keV 5163 /4/
Behrens+ 102 keV - 19.7 MeV 125 /12/(*1)
Moore+ 404 keV - 8.28 MeV 136 /13/
Staples+ 0.514 - 19.5 MeV 124 /14/(*1)
*1) ratio to U-235 fission cross section
The results of GMA were used to determine the parameters in
the CCONE calculation.
MT=19, 20, 21, 38 Multi-chance fission cross sections
Calculated with CCONE code, and renormalized to the total
fission cross section (MT=18).
MF= 4 Angular distributions of secondary neutrons
MT=2 Elastic scattering
Calculated with CCONE code.
MT=18 Fission
Isotropic distributions in the laboratory system were assumed.
MF= 5 Energy distributions of secondary neutrons
MT=18 Fission spectra
Calculated with CCONE code.
MF= 6 Energy-angle distributions
Calculated with CCONE code.
Distributions from fission (MT=18) are not included.
MF=12 Photon production multiplicities
MT=18 Fission
Calculated from the total energy released by the prompt
gamma-rays due to fission which was estimated from its
systematics, and the average energy of gamma-rays.
MF=14 Photon angular distributions
MT=18 Fission
Isotoropic distributions were assumed.
MF=15 Continuous photon energy spectra
MT=18 Fission
Experimental data measured by Verbinski et al./15/ for
Pu-239 thermal fission were adopted.
MF=31 Covariances of average number of neutrons per fission
MT=452 Number of neutrons per fission
Sum of covariances for MT=455 and MT=456.
MT=455
Error of 15% was assumed.
MT=456
Covariance was obtained by fitting a linear function to the
data at 0.0 and 5.0 MeV with an uncertainty of 5%.
MF=32 Covariances of resonance parameters
MT=151 Resolved resonance parameterss
Format of LCOMP=0 was adopted.
Uncertainties of parameters were taken from Mughabghab /16/.
For the parameters without any information on uncertainty,
the following uncertainties were assumed:
Resonance energy 0.1 %
Neutron width 10 %
Capture width 20 %
Fission width 50 %
MF=33 Covariances of neutron cross sections
Covariances were given to all the cross sections by using
KALMAN code/17/ and the covariances of model parameters
used in the cross-section calculations.
For the fission cross section, covariances obtained with the
GMA analysis were adopted. Standard deviation of 90 % was
assumed in the energy region below 5 keV.
In the resolved resonance region, the following standard
deviations were added to the contributions from resonance
parameters:
Total 20 %
Elastic scattering 20 %
MF=34 Covariances for Angular Distributions
MT=2 Elastic scattering
Covariances were given only to P1 components.
MF=35 Covariances for Energy Distributions
MT=18 Fission spectra
Estimated with CCONE and KALMAN codes.
*****************************************************************
Calculation with CCONE code
*****************************************************************
Models and parameters used in the CCONE/9/ calculation
1) Coupled channel optical model
Levels in the rotational band were included. Optical model
potential and coupled levels are shown in Table 1.
2) Two-component exciton model/18/
* Global parametrization of Koning-Duijvestijn/19/
was used.
* Gamma emission channel/20/ was added to simulate direct
and semi-direct capture reaction.
3) Hauser-Feshbach statistical model
* Moldauer width fluctuation correction/21/ was included.
* Neutron, gamma and fission decay channel were included.
* Transmission coefficients of neutrons were taken from
coupled channel calculation in Table 1.
* The level scheme of the target is shown in Table 2.
* Level density formula of constant temperature and Fermi-gas
model were used with shell energy correction and collective
enhancement factor. Parameters are shown in Table 3.
* Fission channel:
Double humped fission barriers were assumed.
Fission barrier penetrabilities were calculated with
Hill-Wheler formula/22/. Fission barrier parameters were
shown in Table 4. Transition state model was used and
continuum levels are assumed above the saddles. The level
density parameters for inner and outer saddles are shown in
Tables 5 and 6, respectively.
* Gamma-ray strength function of Kopecky et al/23/,/24/
was used. The prameters are shown in Table 7.
------------------------------------------------------------------
Tables
------------------------------------------------------------------
Table 1. Coupled channel calculation
--------------------------------------------------
* rigid rotor model was applied
* coupled levels = 0,1,2,3,4 (see Table 2)
* optical potential parameters /11/
Volume:
V_0 = 49.97 MeV
lambda_HF = 0.01004 1/MeV
C_viso = 15.9 MeV
A_v = 12.04 MeV
B_v = 81.36 MeV
E_a = 385 MeV
r_v = 1.2568 fm
a_v = 0.633 fm
Surface:
W_0 = 17.2 MeV
B_s = 11.19 MeV
C_s = 0.01361 1/MeV
C_wiso = 23.5 MeV
r_s = 1.1803 fm
a_s = 0.601 fm
Spin-orbit:
V_so = 5.75 MeV
lambda_so = 0.005 1/MeV
W_so = -3.1 MeV
B_so = 160 MeV
r_so = 1.1214 fm
a_so = 0.59 fm
Coulomb:
C_coul = 1.3
r_c = 1.2452 fm
a_c = 0.545 fm
Deformation:
beta_2 = 0.24761
beta_4 = 0.03641
beta_6 = -0.02816
* Calculated strength function
S0= 0.95e-4 S1= 2.84e-4 R'= 9.31 fm (En=1 keV)
--------------------------------------------------
Table 2. Level Scheme of Pu-244
-------------------
No. Ex(MeV) J PI
-------------------
0 0.00000 0 + *
1 0.04420 2 + *
2 0.15500 4 + *
3 0.31790 6 + *
4 0.53500 8 + *
5 0.70800 2 +
6 0.80240 10 +
7 0.95700 3 -
-------------------
*) Coupled levels in CC calculation
Table 3. Level density parameters
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Pu-245 18.8322 0.7667 2.7988 0.3349 -0.4502 2.4667
Pu-244 18.7661 1.5364 2.7670 0.3408 0.2726 3.2969
Pu-243 18.6999 0.7698 2.4578 0.3280 -0.3352 2.3315
Pu-242 18.6337 1.5428 2.4520 0.3701 0.0291 3.6198
Pu-241 18.5675 0.7730 2.1853 0.3473 -0.4715 2.5167
--------------------------------------------------------
Table 4. Fission barrier parameters
----------------------------------------
Nuclide V_A hw_A V_B hw_B
MeV MeV MeV MeV
----------------------------------------
Pu-245 5.600 0.530 5.300 0.520
Pu-244 6.000 1.040 4.700 0.600
Pu-243 5.750 0.680 5.520 0.520
Pu-242 6.150 1.000 4.800 0.600
Pu-241 5.950 0.580 5.480 0.520
----------------------------------------
Table 5. Level density above inner saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Pu-245 20.7155 0.8944 2.6000 0.3269 -1.5284 2.8944
Pu-244 20.6427 1.7925 2.6000 0.3275 -0.6303 3.7925
Pu-243 20.5699 0.8981 2.6000 0.3633 -2.0616 3.3981
Pu-242 20.4971 1.7999 2.6000 0.3433 -0.8376 3.9999
Pu-241 20.4242 0.9018 2.6000 0.3647 -2.0579 3.4018
--------------------------------------------------------
Table 6. Level density above outer saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Pu-245 20.7155 0.8944 0.6200 0.3609 -0.8159 2.8944
Pu-244 20.6427 1.7925 0.5800 0.3621 0.0827 3.7925
Pu-243 20.9439 0.8981 0.5400 0.3740 -0.9758 3.0981
Pu-242 20.4971 1.7999 0.5000 0.3933 -0.2466 4.1999
Pu-241 20.4242 0.9018 0.4600 0.3804 -0.9744 3.1018
--------------------------------------------------------
Table 7. Gamma-ray strength function for Pu-245
--------------------------------------------------------
K0 = 1.500 E0 = 4.500 (MeV)
* E1: ER = 10.90 (MeV) EG = 2.50 (MeV) SIG = 300.00 (mb)
ER = 13.80 (MeV) EG = 4.70 (MeV) SIG = 450.00 (mb)
* M1: ER = 6.55 (MeV) EG = 4.00 (MeV) SIG = 2.63 (mb)
* E2: ER = 10.07 (MeV) EG = 3.17 (MeV) SIG = 6.77 (mb)
--------------------------------------------------------
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