96-Cm-247 JAEA+ EVAL-FEB10 O.Iwamoto, T.Nakagawa, et al.
DIST-MAY10 20100318
----JENDL-4.0 MATERIAL 9646
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
05-06 Fission cross section was evaluated with GMA.
06-05 Resonance parameters were modified.
06-12 GMA results were revised.
07-05 New calculation was made with CCONE code.
08-03 Recalculation with CCONE code was performed.
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's=455 and 456.
MT=455 Delayed neutron data
(same as JENDL-3.3)
Semi-empirical formula by Tuttle/2/.
MT=456 Number of prompt neutrons per fission
(same as JENDL-3.3)
At the 0 eV, the experimental data of Zhuravlev et al./3/
was adopted. An energy-dependent term was based on the semi-
empirical formula by Howerton/4/.
MF= 2 Resonance parameters
MT=151
Resolved resonance parameters (MLBW: 1.0E-5 - 60 eV)
Resonance parameters of Moore and Keyworth/5/ and Danon
et al./6/ were adopted. Resonance energies of Ref./5/ were
shifted down by 0.3%. The parameters were adjusted to the
measured fission cross sections/5,6/.
The thermal cross sections to be reproduced:
Fission = 94.6 +- 3.1 b
Danon et al./6/, Diamond et al./7/, Benjamin et al./8/,
Zhuravlev et al./9/, etc.
Capture = 60 +- 10 b
Gavrilov et al./10/
Unresolved resonance parameters (60 eV - 40 keV)
Parameters were determined with ASREP code/11/ so as to
reproduce the cross sections. They are used only for self-
shielding calculations.
Thermal cross sections and resonance integrals (at 300K)
-------------------------------------------------------
0.0253 eV reson. integ.(*)
(barns) (barns)
-------------------------------------------------------
total 163.023
elastic 8.348
fission 94.744 945
capture 59.931 503
-------------------------------------------------------
(*) 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/12/.
MT= 1 Total cross section
The cross section was calculated with CC OMP of Soukhovitskii
et al./13/
MT= 2 Elastic scattering cross section
Calculated as total - non-elastic scattering cross sections.
MT=18 Fission cross section (Above 115 eV)
The following experimental data were analyzed in the energy
range from 115 eV to 20 MeV with the GMA code /14/:
Authors Energy range Data points Reference
Moore+ 50eV - 1.9MeV 3523 /5/
Fomushkin+ 20keV - 3MeV 27 /15/
Fomushkin+ 14 MeV 1 /16/
Danon+ 500eV - 98keV 45 /17/
Danon+ 0.01eV - 9.8keV 1018 /6/
Ivanin+ 130keV - 8.3MeV 81 /18/
Fursov+ 135keV - 15MeV 68 /19/(*1)
(*1) Ratio to Pu-239 fission. JENDL-3.3 data were used to
convert them to cross sections.
The results of GMA were used to determine the parameters in
the CCONE calculation.
In the energy regions from 40 to 500keV and above 6 MeV,
eye-guided curves were adopted.
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 Prompt neutron spectra
Calculated with CCONE code/12/.
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./20/ 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 4% and 5%,
respevtively. The uncertainty at 0 eV was estimated from the
experimental data of Zhuravlev et al./3/
MF=32 Covariances of resonance parameters
MT=151 Resolved resonance parameterss
Format of LCOMP=0 was adopted.
Uncertainties of parameters were taken from Mughabghab /21/.
For the parameters without any information on uncertainty,
the following uncertainties were assumed:
Resonance energy 0.1 %
Neutron width 10 %
Capture width 30 %
Fission width 20 %
They were further modified by considering experimental data
of the fission cross section at the thermal neutron energy.
MF=33 Covariances of neutron cross sections
Covariances were given to all the cross sections by using
KALMAN code/22/ 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 deviations of about 10%
were assumed in the energy region above 8 MeV.
In the resolved resonance region, the following standard
deviations were added to the contributions from resonance
parameters:
Total 10 %
Elastic scattering 20 %
Capture 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/12/ 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/23/
* Global parametrization of Koning-Duijvestijn/24/
was used.
* Gamma emission channel/25/ was added to simulate direct
and semi-direct capture reaction.
3) Hauser-Feshbach statistical model
* Moldauer width fluctuation correction/26/ 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/27/. 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/28/,/29/
was used. The prameters are shown in Table 7.
------------------------------------------------------------------
Tables
------------------------------------------------------------------
Table 1. Coupled channel calculation
--------------------------------------------------
* rigid rotor model was applied
* coupled levels = 0,1,2,3,33 (see Table 2)
* optical potential parameters /13/
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 = 0.213
beta_4 = 0.066
beta_6 = 0.0015
* Calculated strength function
S0= 1.18e-4 S1= 2.99e-4 R'= 9.09 fm (En=1 keV)
--------------------------------------------------
Table 2. Level Scheme of Cm-247
-------------------
No. Ex(MeV) J PI
-------------------
0 0.00000 9/2 - *
1 0.06167 11/2 - *
2 0.13465 13/2 - *
3 0.21900 15/2 - *
4 0.22738 5/2 +
5 0.26586 7/2 +
6 0.28541 7/2 +
7 0.30900 9/2 -
8 0.31830 9/2 +
9 0.33600 7/2 +
10 0.34590 9/2 +
11 0.37000 13/2 -
12 0.38100 11/2 +
13 0.39800 11/2 +
14 0.40490 1/2 +
15 0.41700 9/2 +
16 0.43300 3/2 +
17 0.43900 13/2 +
18 0.44800 5/2 +
19 0.50600 1/2 +
20 0.51670 7/2 +
21 0.51858 3/2 +
22 0.55000 9/2 +
23 0.58170 5/2 +
24 0.59200 9/2 +
25 0.60400 7/2 +
-------------------
*) Coupled levels in CC calculation
Table 3. Level density parameters
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Cm-248 18.5357 1.5240 2.0504 0.3482 0.2818 3.2555
Cm-247 18.3955 0.7635 1.7794 0.3734 -0.6804 2.7533
Cm-246 18.8984 1.5302 1.7310 0.3608 0.1621 3.4286
Cm-245 18.8322 0.7667 1.4601 0.3623 -0.5771 2.6382
Cm-244 19.1414 1.5364 1.5347 0.3530 0.2436 3.3454
--------------------------------------------------------
Table 4. Fission barrier parameters
----------------------------------------
Nuclide V_A hw_A V_B hw_B
MeV MeV MeV MeV
----------------------------------------
Cm-248 6.100 1.040 4.950 0.600
Cm-247 5.400 0.800 5.650 0.650
Cm-246 6.300 1.040 5.100 0.600
Cm-245 6.050 0.500 5.700 0.420
Cm-244 6.100 0.900 5.100 0.600
----------------------------------------
Table 5. Level density above inner saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Cm-248 20.9336 1.5000 2.6000 0.3323 -1.0300 3.6000
Cm-247 20.8609 0.8908 2.6000 0.3256 -1.5320 2.8908
Cm-246 20.7882 1.6500 2.6000 0.3263 -0.7728 3.6500
Cm-245 20.7155 0.8944 2.6000 0.3342 -1.6357 2.9944
Cm-244 20.6427 1.7925 2.6000 0.3275 -0.6303 3.7925
--------------------------------------------------------
Table 6. Level density above outer saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Cm-248 20.9336 1.7780 0.8600 0.3706 -0.1043 3.9780
Cm-247 20.8609 0.8908 0.8200 0.3573 -0.8210 2.8908
Cm-246 20.7882 1.7852 0.7800 0.3658 -0.0107 3.8852
Cm-245 20.7155 0.8944 0.7400 0.3596 -0.8163 2.8944
Cm-244 20.6427 1.7925 0.7000 0.3455 0.2502 3.5925
--------------------------------------------------------
Table 7. Gamma-ray strength function for Cm-248
--------------------------------------------------------
* E1: ER = 11.40 (MeV) EG = 2.71 (MeV) SIG = 331.48 (mb)
ER = 14.30 (MeV) EG = 4.18 (MeV) SIG = 429.81 (mb)
* M1: ER = 6.53 (MeV) EG = 4.00 (MeV) SIG = 1.48 (mb)
* E2: ER = 10.03 (MeV) EG = 3.13 (MeV) SIG = 7.06 (mb)
--------------------------------------------------------
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