90-Th-230 JAEA+ EVAL-FEB10 O.Iwamoto, T.Nakagawa, et al.
DIST-MAY10 20100318
----JENDL-4.0 MATERIAL 9034
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
05-11 Fission cross section was evaluated with GMA code.
07-06 Theoretical calculation was performed with CCONE code.
07-07 Data were compiled as JENDL/AC-2008/1/.
10-02 Data of prompt gamma rays due to fission were given.
Nu-tptal, nu-p and nu-d were revised.
10-03 Covariance data were added.
MF=1 General information
MT=452 Number of Neutrons per fission
Sum of MT's=455 and 456.
MT=455 Delayed neutron data
Average values of systematics of Tuttle/2/, Benedetti et
al./3/ and Waldo et al./4/
MT=456 Number of prompt neutrons per fission
Fitting to the experimental data of Boldeman/5/.
MF= 2 Resonance parameters
MT=151
Resolved resonance parameters (MLBW: 10e-5 - 500 eV)
Parameters of JENDL-3.3 were based on the parameters obtained
by Kalebin et al./6/ These parameters were revised to
reproduce the capture cross section at 0.0253 eV.
Capture = 23.4 +- 1.1 b
Pomerance/7/, Cabell/8/
Fission widths were ignored. The fission cross section is
given as background cross sections.
Unresolved resonance parameters (0.5 - 70 keV)
Parameters (URP) were determined with ASREP code/9/ so as to
reproduce the cross sections in this energy region. URP are
used only for self-shielding calculations.
Thermal cross sections and resonance integrals (at 300K)
-------------------------------------------------------
0.0253 eV reson. integ.(*)
(barns) (barns)
-------------------------------------------------------
total 32.813
elastic 10.392
fission 0.0095 0.786
capture 23.411 1040
-------------------------------------------------------
(*) In the energy range from 0.5 eV to 10 MeV.
Kalebin et al./6/ reported the total cross section of 70+-
3.8b at 0.0253 eV. This data was ignored because it was too
large.
MF= 3 Neutron cross sections
Cross sections above the resolved resonance region except for
elastic scattering and fission cross sections (MT's =2, 18-21,
38) were calculated with CCONE code/10/.
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-elstic scattering cross sections
MT=18 Fission cross section
Below 260 eV, 1/v shape was assumed. The cross section at 1
eV was assumed to be 1.51 mb which was determined from CCONE
calculation/10/ reducing by a factor of 0.04 because
experimental data for Th-232 are smaller by a factor of about
0.04 than CCONE calculation.
From 260 eV to 100 keV, assumed to be 9 micro-b.
From 100 to 400 keV, calculated with CCONE code.
In the energy range from 400 keV to 9 MeV, the following
experimental data were analyzed with the GMA code/12/:
Authors Energy range Data points Reference
Karzarinora+ 14.6 MeV 1 /13/
Muir+ 0.3 - 2.96 MeV 181 /14/
James+ 0.625 - 1.4 MeV 50 /15/
Meadows 0.737 - 9.4 MeV 15 /16/(*1)
Blons+ 0.5 - 4 MeV 1764 /17/
Boldeman+ 0.697 - 0.744 MeV 68 /18/
Meadows 14.7 MeV 1 /19/(*1)
Petit+ 1 -9.9 MeV 90 /20/
(*1) Relative measurment to U-235 fission. They were
converted to Th-230 fission by using JENDL-3.3 data.
Above 10 MeV, results of CCONE calculation were adopted.
The parameters of CCONE were adjusted using the results of
GMA bellow 9 MeV and the experimental data of Meadows/19/
above 9 MeV.
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/10/.
MT=18 Fission
Isotropic distributions in the laboratory system were assumed.
MF= 5 Energy distributions of secondary neutrons
MT=18 Prompt neutrons
Calculated with CCONE code/10/.
MF= 6 Energy-angle distributions
Calculated with CCONE code/10/.
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./21/ for
U-235 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 /22/.
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 20 %
They were further modified by considering experimental data
of the capture 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/23/ 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 (SD) were
multiplied by a factor of 1.5. SD's of 75% and 18% were assumed
in the energy region below 400 keV and above 10 MeV,
respectively.
In the resolved resonance region, the following standard
deviations were added to the contributions from resonance
parameters:
Total 2 b
Elastic scattering 20 %
Fission 50 %
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/10/ 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/24/
* Global parametrization of Koning-Duijvestijn/25/
was used.
* Gamma emission channel/26/ was added to simulate direct
and semi-direct capture reaction.
3) Hauser-Feshbach statistical model
* Moldauer width fluctuation correction/27/ 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/28/. 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/29/,/30/
was used. The prameters are shown in Table 7.
------------------------------------------------------------------
Tables
------------------------------------------------------------------
Table 1. Coupled channel calculation
--------------------------------------------------
* rigid rotor model was applied
* coupled levels = 0,1,2,3,6 (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 = 0.213
beta_4 = 0.066
beta_6 = 0.0015
* Calculated strength function
S0= 0.98e-4 S1= 2.42e-4 R'= 9.82 fm (En=1 keV)
--------------------------------------------------
Table 2. Level Scheme of Th-230
-------------------
No. Ex(MeV) J PI
-------------------
0 0.00000 0 + *
1 0.05320 2 + *
2 0.17410 4 + *
3 0.35660 6 + *
4 0.50816 1 -
5 0.57177 3 -
6 0.59410 8 + *
7 0.63490 0 +
8 0.67760 2 +
9 0.68670 5 -
-------------------
*) Coupled levels in CC calculation
Table 3. Level density parameters
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Th-231 18.7090 0.7895 3.3191 0.3770 -0.9082 3.0943
Th-230 18.6395 1.5825 3.2401 0.4059 -0.4442 4.2813
Th-229 18.1256 0.7930 3.2566 0.4250 -1.3952 3.6819
Th-228 17.7035 1.5894 3.0590 0.3964 -0.1539 3.9563
Th-227 17.6369 0.7965 3.1200 0.4219 -1.2457 3.5201
--------------------------------------------------------
Table 4. Fission barrier parameters
----------------------------------------
Nuclide V_A hw_A V_B hw_B
MeV MeV MeV MeV
----------------------------------------
Th-231 5.800 0.800 6.050 0.550
Th-230 6.000 1.040 5.800 0.500
Th-229 5.500 0.800 6.000 0.520
Th-228 3.900 1.040 6.400 0.600
Th-227 4.100 0.800 6.400 0.520
----------------------------------------
Table 5. Level density above inner saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Th-231 19.6937 0.9211 2.6000 0.3507 -1.7165 3.1211
Th-230 19.9772 1.8463 2.6000 0.3178 -0.3511 3.6463
Th-229 19.9026 0.9251 2.6000 0.3339 -1.4862 2.9251
Th-228 19.8280 1.8543 2.6000 0.3346 -0.5570 3.8543
Th-227 19.7533 0.9292 2.6000 0.3352 -1.4822 2.9292
--------------------------------------------------------
Table 6. Level density above outer saddle
--------------------------------------------------------
Nuclide a* Pair Eshell T E0 Ematch
1/MeV MeV MeV MeV MeV MeV
--------------------------------------------------------
Th-231 19.3357 0.9211 -0.1800 0.4080 -1.0331 3.2211
Th-230 20.1556 1.8463 -0.2200 0.3610 0.3158 3.6463
Th-229 19.1918 0.9251 -0.2600 0.3882 -0.7797 2.9251
Th-228 19.8280 1.8543 -0.3000 0.3812 0.1590 3.8543
Th-227 19.7533 0.9292 -0.3400 0.3826 -0.7655 2.9292
--------------------------------------------------------
Table 7. Gamma-ray strength function for Th-231
--------------------------------------------------------
K0 = 1.502 E0 = 4.500 (MeV)
* E1: ER = 11.03 (MeV) EG = 2.71 (MeV) SIG = 302.00 (mb)
ER = 13.87 (MeV) EG = 4.77 (MeV) SIG = 449.00 (mb)
* M1: ER = 6.68 (MeV) EG = 4.00 (MeV) SIG = 2.80 (mb)
* E2: ER = 10.27 (MeV) EG = 3.34 (MeV) SIG = 6.25 (mb)
--------------------------------------------------------
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