90-Th-232
90-Th-232 Kinki U. Eval-Jul01 T.Ohsawa
DIST-MAR02 REV4-AUG01 20010807
----JENDL-3.3 MATERIAL 9040
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
87-03 Re-valuation was made by T. Ohsawa (Kinki University).
The following parts of previous evaluation /1/ were revised
with new one.
Resonance parameters, elastic and inelastic scattering,
Nu-p, Nu-d, energy distributions of neutrons.
88-09 Fission cross section was modified a little.
89-02 Fission product yields (MF=8) were replaced with JNDC FP
Decay File version-2.
89-04 Fission spectrum was modified.
Compilation was made by T. Nakagawa(JAERI).
93-08 JENDL-3.2.
Compiled by T.Nakagawa (NDC/JAERI)
01-07 JENDL-3.3
Re-evaluated by T.Ohsawa, and compiled by T.Nakagawa
***** Modified parts from JENDL-3.2 *******************
(2,151) Parameters of low-lying levels
(3,18), (3,102) Background cross sections in the thermal
region, and direct and semi-direct
capture
(4,2) at 2 MeV
(5,455)
(5,16),(5,17),(5.91) Interpolation changed to 22.
***********************************************************
MF=1 General Information
MT=451 Descriptive data and dictionary
MT=452 Number of Neutrons per Fission
Sum of prompt and delayed neutrons.
MT=455 Delayed Neutrons per Fission
Nu-d based on Tuttle's recommendation /2/.
MT=456 Prompt Neutrons per FIssion
Taken from Davey's recommendation /3/.
Decay contants were taken from Brady and England /4/.
MF=2 Resonance Parameters
MT=151 Resolved and Unresolved Resonance Parameters
Resolved resonances for MLBW formula : 1.0E-5 eV - 3.5 keV
The parameters of JENDL-2 which were mainly based on
Ref./5/ and BNL 325(3rd) were modified as follows:
(1) For 22 resonances in the lower energy region which make
major contribution to the resonance integral, the new
parameters of Kobayashi /6/ were adopted;
(2) The average radiative width of 24.7 meV were attributed
to those resonances for which the radiative width was
not known.
For JENDL-3.3, negative energy resonance parameters and
scattering radius were adjusted and 1/v-background cross
section was given to the capture cross section so as to
reproduce the following features simultaneously:
Capture cross section of 7.40 b at 0.0253 eV, Capture
cross section curve of Chrien et al./7/ in the region
0.04 - 10 eV, Total cross section curve of Kobayashi et
al./8/ in the region 0.04 - 10 eV.
Unresolved resonances : 3.5 keV - 50 keV
Average resonance parameters were given. The energy
dependent S0 and S1 were calculated so as to reproduce the
total and capture cross sections in this region.
Fixed parameters :
GG = 0.0212 eV, D-obs = 18.64 eV, R = 10.01 fm.
Typical strength functions at 10 keV :
S0 = 0.93E-4, S1 = 1.96E-4
Calculated 2200-m/sec cross sections and resonance integrals
2200 m/sec Res. integ.
total 20.12 b ---
elastic 12.72 b ---
fission 5.4e-5 b 0.636 b
capture 7.40 b 85.0 b
MF=3 Neutron Cross Sections
Below 3.5 keV :
Background cross section is given for the capture.
Above 50 keV :
MT=1 Total
Based on the experimental data of Whalen/9/, Foster/10/ and
Fasoli/11/ in the size resonance region, and Kobayashi/8/,
Whalen/9/ and Uttley/12,13/ below 1.5 MeV, and optical
model calculation above 14 MeV.
MT=2 Elastic Scattering
Obtained by subtracting the sum of capture, inelastic,
fission, (n,2n), (n,3n) cross sections from the total cross
section.
MT=4 Total Inelastic Scattering Cross Section
Sum of partial inelastic scattering cross sections.
MT=16 (n,2n)
Calculated with the model of Segev et al./14/.
MT=17 (n,3n)
Calculated with the model of Segev et al./14/.
MT=18 Fission
The ratio data Th-232/U-235 of Behrens/15/ were multiplied
with the evaluated data/16/ of U-235(n,f).
Subthreshold fission cross section data of Nakagome et al.
/17/ were adopted below 0.6 MeV.
MT=51-52 Inelastic scattering to the 1st and 2nd levels.
Calculated with consistent combination of coupled-channel
(CC) and Hauser-Feshbach(HF) methods (CC/HF method)/18/.
The code JUPITOR-1/19/ was used for CC-calculations,
ELIESE-3/20/ for the HF-calculations.
MT=55,59,62,66 Inelastic scattering to the 5th, 9th, 12th
and 16th levels.
Compound nuclear component was calculated with the code
ELIESE-3 using the generalized transmission coefficients
calculated with JUPITOR-1 for the entrance channel. Direct
reaction component was calculated with the code DWUCK/21/.
MT=53,54,56-58,60,61,63-65,67-70,91 Inelastic scattering
to the other discrete and continuum levels.
Calculated with ELIESE-3 using the generalized trans-
mission coefficients for the entrance channel.
MT=102 Capture
Based on the measurement of Kobayashi/22/ and calculation
with the code CASTHY/23/. Direct/semi-direct capture
component calculated with the code DSD /24/ was added to
the CASTHY calculation above 1 MeV.
The parameters for the CC and spherical optical potentials
were taken from Haouat et al./25/ and Ohsawa et al./26/,
respectively:
CC SOM
V = 46.4-0.3*En V = 41.0-0.05*En (MeV)
Ws = 3.6+0.4*En Ws = 6.4+0.15*SQRT(En)(MeV)
Vso= 6.2 Vso= 7.0 (MeV)
r = 1.26 r = 1.31 (fm)
rs = 1.26 rs = 1.38 (fm)
rso= 1.12 rso= 1.31 (fm)
a = 0.63 a = 0.47 (fm)
as = 0.52 as = 0.47 (fm)
aso= 0.47 aso= 0.47 (fm)
beta2=0.190
beta4=0.071
The level scheme was taken from Ref./27/.
No. Energy(MeV) Spin-Parity
gs 0 0+
1 0.049 2+
2 0.162 4+
3 0.333 6+
4 0.557 8+
5 0.714 1-
6 0.730 0+
7 0.7741 2+
8 0.7743 3-
9 0.785 2+
10 0.830 3-
11 0.873 4+
12 0.883 5-
13 0.889 4+
14 0.960 5+
15 1.054 2-
16 1.073 2+
17 1.0777 1-
18 1.078 0+
19 1.094 3+
20 1.105 3-
Continuum levels were assumed above 1.110MeV.
The level density parameters of Gilbert and Cameron/28/
were used.
MT=251 Mu-bar
Calculated with the optical model.
MF=4 Angular Distributions of Secondary Neutrons
MT=2 Elastic scattering
Calculated with CC/HF method/18/.
MT=51-70 Inelastic
Calculated with CC/HF method/18/ and DWBA/21/.
MT=16,17,18,91 (n,2n), (n,3n), fission and continuum inelastic
Assumed to be isotropic in the LAB system.
MF=5 Energy Distributions of Secondary Neutrons
MT=16,17,91 (n,2n), (n,3n) and continuum inelastic
Calculated with PEGASUS/29/.
MT=18 Fission
Maxwell spectrum. The temperature parameters were estimated
from the systematics of Howerton-Doyas/30/.
MT=455 Delayed Neutrons
Spectrum calculated by Brady and England /4/ was adopted.
Relative abundance was taken from Ref./31/.
MF=8 Fission Product Yield Data
MT=454 Independent Yields
Taken from JNDC FP Decay File version-2/32/.
MT=459 Cumulative Yields
Taken from JNDC FP Decay File version-2/32/.
References
1) Ohsawa,T., et al.; J. Nucl. Sci. Technol., 18, 408 (1981).
2) Tuttle,R.J., et al.; INDC(NDS)-107/G, p.29 (1979).
3) Davey,W.G.; Nucl. Sci. Eng., 44, 345 (1971).
4) Brady,M.C. and England,T.R.: Nucl. Sci. Eng., 103, 129 (1989).
5) Rahn,F., et al.; Phys. Rev., C6, 1854 (1972).
6) Kobayashi,K.; Private communication (1986).
7) Chrien, R.E., et al.: Nucl. Sci. Eng., 72, 202 (1979).
8) Kobayashi,K., et al.; Nucl. Sci. Eng., 65, 347 (1978).
9) Whalen,F.F., and Smith,A.B.; Nucl. Sci. Eng., 67, 129 (1978).
10) Foster,D.G. et al.; Private communication (1967); Phys. Rev.
C3, 596 (1971)
11) Fasoli,U., et al.; Nucl. Phys., A151, 369 (1970).
12) Uttley,C.A., et al.; EANDC Conf. on TOF Methods, Saclay(1961)
p.109
13) Uttley,C.A., et al.; Proc. 1st Conf. on Nuclear Data for
Reactors, Paris (1966).
14) Segev,M., et al.; Ann. Nucl. Energy 5, 239 (1978).
15) Behrens,J.W., et al.; UCID-17442 (1977); Phys. Lett. 69B, 278
(1977).
16) Matsunobu,H.; Private communication (1979).
17) Nakagome,Y.,et al.: Phys. Rev., C43, 1824 (1991).
18) Ohsawa,T., et al.; Proc. Int. Conf. on Nuclear Data for Basic
and Applied Science (1985) Vol.2, p.1193
19) Tamura,T.; Rev. Mod. Phys., 37, 679 (1965).
20) Igarasi,S.; JAERI-1223 (1973).
21) Kunz,P.D.; COO-535-606 and -613 (1969).
22) Kobayashi,K., et al; Preprint 1978 Fall Mtg. at. Energy Soc.
Japan, D23 (1978).
23) Igarasi,S. and Fukahori,T.; JAERI 1321 (1991).
24) Kawano,T.: private communication (1999).
25) Haouat,G., et al.; Nucl. Sci. Eng., 81, 491 (1982).
26) Ohsawa,T. et al.; J. Nucl. Sci. Technol., 18, 408 (1980).
27) Chan,D.W.S., et al.; Phys. Rev., C26, 841 (1982).
28) Gilbert,A. and Cameron,A.G.W.; Can. J. Phys., 24, 63 (1965).
29) Iijima,S., et al.; JAERI-M 87-025, p.337 (1987).
30) Howerton,R.J. and Doyas,R.J.; Nucl.Sci. Eng., 46, 414 (1971).
31) Keepin,G.R., et al.; Phys. Rev., 107, 1044 (1957).
32) JNDC Decay Heat Evaluation WG; private communication (1989).