56-Ba-137
56-Ba-137 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.
DIST-MAY10 20091217
----JENDL-4.0 MATERIAL 5646
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
===========================================================
Resonance parameters in JENDL-3.3 were revised for JENDL-4.
===========================================================
===========================================================
JENDL-3.2 data were automatically transformed to JENDL-3.3.
Interpolation of spectra: 22 (unit base interpolation)
(3,251) deleted, T-matrix of (4,2) deleted, and others.
===========================================================
History
84-10 Evaluation for JENDL-2 was made by JNDC FPND W.G./1/
90-03 Modification for JENDL-3 was made/2/.
93-10 JENDL-3.2 was made by JNDC FPND W.G.
***** modified parts for JENDL-3.2 ********************
(2,151) Resolved resonance parameters were modified.
***********************************************************
10-03 JENDL-4.0 was made.
Resoloved resonance parameters were evaluated by K.Shibata.
Unresolved resonance parameters were evaluated by S.Kunieda.
The LSSF=1 was applied.
Compiled by S.Kunieda
***** modified parts for JENDL-4.0 ********************
(1,451) Updated.
(2,151) Updated.
(3,1) Re-calculated from partial cross sections.
(3,2) Calculated from URP in lower energy range.
(3,4) Re-calculated from partial cross sections.
(3,102) Calculated from URP in lower energy range.
***********************************************************
mf = 1 General information
mt=451 Comments and dictionary
mf = 2 Resonance parameters
mt=151 Resolved and unresolved resonance parameters
Resolved resonance region (MLBW formula) : below 11.885 keV
For JENDL-2, evaluation was made by Kikuchi/3/. Below 1.7
keV, parameters were determined from the experimental data of
Alves et al./4/ and Van de Vyver and Pattenden/5/. Average
radiation widths were assumed to be 0.08 eV for s-wave
resonances and 0.068 eV for p-wave ones except for 420- and
578-eV levels. Above 3 keV, evaluation was based on the data
of Musgrove et al./6/. Many artificial levels were generated
with stat/7/ by assuming d=380 eV, S0=0.57e-4, S1=0.45e-4. A
negative resonance was added at -26 eV so as to reproduce the
capture cross section of 5.1 +- 0.4 barns at 0.0253 eV/8/.
For JENDL-3, the resonance parameters of JENDL-2 were
updated by using the newest experimental data by Mizumoto /9/.
The resonance energies and neutron widths were replaced by
Mizumoto's data in the energy range from 418.3 eV to 14.941
keV. Average radiation width and scattering radius were taken
from Mughabghab et al./8/ total spin J of some resonances was
tentatively estimated with a random number method.
*************************************************************
In JENDL-4, the parameters for the negative resonance was
re-adjusted so as to reproduce the thermal capture cross
section recommended by Mughabghab./26/
*************************************************************
Unresolved resonance region : 11.885 keV - 100 keV
Initial values of neutron strength functions, S0 and S1, were
adopted from the recommendation by Mughabghab et al., and S2
was taken from calculation with CASTHY/10/. The parameters
were adjusted to reproduce the capture cross section measured
by Musgrove et al./11/ The effective scattering radius was
obtained from fitting to the calculated total cross section at
100 keV. The radiation width Gg was adopted from Ref./8/.
Typical values of the parameters at 70 keV:
S0 = 0.695e-4, S1 = 0.525e-4, S2 = 0.949e-4, Sg = 3.91e-4,
Gg = 0.080 eV, R = 5.729 fm.
***************************************************************
For JENDL-4.0, the unresolved resonance parameters were
re-evaluated by the ASREP /27/ code so as to reproduce the
total and capture cross sections given in JENDL3.3 in the
energy region from 11.885 keV to 100 keV. The parameters
should be used only for self-shielding calculations.
***************************************************************
Thermal cross sections & resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 7.49733E+00
Elastic 3.89613E+00
n,gamma 3.60120E+00 4.25658E+00
----------------------------------------------------------
(*) Integrated from 0.5 eV to 10 MeV.
mf = 3 Neutron cross sections
Below 100 keV, resonance parameters were given.
Above 100 keV, the spherical optical and statistical model
calculation was performed with CASTHY, by taking account of
competing reactions, of which cross sections were calculated
with PEGASUS/12/ standing on a preequilibrium and multi-step
evaporation model. The OMP's for neutron given in Table 1 were
determined to reproduce a systematic trend of the total cross
section by changing Ws and rso of Iijima-Kawai potential/13/.
The OMP's for charged particles are as follows:
proton = Perey/14/
alpha = Huizenga and Igo/15/
deuteron = Lohr and Haeberli/16/
helium-3 and triton = Becchetti and Greenlees/17/
Parameters for the composite level density formula of Gilbert
and Cameron/18/ were evaluated by Iijima et al./19/ More
extensive determination and modification were made in the
present work. Table 2 shows the level density parameters used
in the present calculation. Energy dependence of spin cut-off
parameter in the energy range below E-joint is due to Gruppelaar
/20/.
mt = 1 Total
Spherical optical model calculation was adopted.
mt = 2 Elastic scattering
Calculated as (total - sum of partial cross sections).
mt = 4, 51 - 91 Inelastic scattering
Spherical optical and statistical model calculation was
adopted. The level scheme was taken from Ref./21/.
no. energy(MeV) spin-parity
gr. 0.0 3/2 +
1 0.2792 1/2 +
2 0.6616 11/2 -
3 1.2900 5/2 +
4 1.4629 5/2 +
5 1.7900 7/2 -
6 1.8400 1/2 +
7 1.9000 5/2 +
8 2.0400 5/2 +
Levels above 2.12 MeV were assumed to be overlapping.
mt = 102 Capture
Spherical optical and statistical model calculation with
CASTHY was adopted. Direct and semi-direct capture cross
sections were estimated according to the procedure of Benzi
and Reffo/22/ and normalized to 1 milli-barn at 14 MeV.
The gamma-ray strength function (3.65e-04) was adjusted to
reproduce the capture cross section of 33 milli-barns at 100
keV measured by Musgrove et al./11/
mt = 16 (n,2n) cross section
mt = 17 (n,3n) cross section
mt = 22 (n,n'a) cross section
mt = 28 (n,n'p) cross section
mt = 32 (n,n'd) cross section
mt =103 (n,p) cross section
mt =104 (n,d) cross section
mt =105 (n,t) cross section
mt =107 (n,alpha) cross section
These reaction cross sections were calculated with the
preequilibrium and multi-step evaporation model code PEGASUS.
The Kalbach's constant k (= 435.5) was estimated by the
formula derived from Kikuchi-Kawai's formalism/23/ and level
density parameters.
Finally, the (n,2n), (n,p) and (n,alpha) cross sections were
normalized to the following values at 14.5 MeV:
(n,2n) 1710.00 mb (systematics of Wen Den Lu+/24/)
(n,p) 3.32 mb (systematics of Forrest/25/)
(n,alpha) 1.59 mb (systematics of Forrest)
mt = 251 mu-bar
Calculated with CASTHY.
mf = 4 Angular distributions of secondary neutrons
Legendre polynomial coefficients for angular distributions are
given in the center-of-mass system for mt=2 and discrete inelas-
tic levels, and in the laboratory system for mt=91. They were
calculated with CASTHY. For other reactions, isotropic distri-
butions in the laboratory system were assumed.
mf = 5 Energy distributions of secondary neutrons
Energy distributions of secondary neutrons were calculated with
PEGASUS for inelastic scattering from overlapping levels and for
other neutron emitting reactions.
TABLE 1 NEUTRON OPTICAL POTENTIAL PARAMETERS
DEPTH (MEV) RADIUS(FM) DIFFUSENESS(FM)
---------------------- ------------ ---------------
V = 41.8 R0 = 6.89 A0 = 0.62
WS = 2.95+0.789E RS = 7.098 AS = 0.35
VSO= 7.0 RSO= 6.89 ASO= 0.62
THE FORM OF SURFACE ABSORPTION PART IS DER. WOODS-SAXON TYPE.
TABLE 2 LEVEL DENSITY PARAMETERS
NUCLIDE A(1/MEV) T(MEV) C(1/MEV) EX(MEV) PAIRING
---------------------------------------------------------------
54-XE-133 1.600E+01 6.250E-01 2.327E+00 5.284E+00 1.120E+00
54-XE-134 1.400E+01 6.300E-01 3.184E-01 5.224E+00 1.820E+00
54-XE-135 1.550E+01 5.565E-01 7.506E-01 4.010E+00 1.120E+00
54-XE-136 1.400E+01 6.500E-01 3.270E-01 5.679E+00 1.970E+00
55-CS-134 1.598E+01 6.450E-01 1.710E+01 4.505E+00 0.0
55-CS-135 1.343E+01 6.537E-01 1.831E+00 4.203E+00 7.000E-01
55-CS-136 1.400E+01 6.000E-01 4.424E+00 2.967E+00 0.0
55-CS-137 1.336E+01 6.200E-01 9.986E-01 3.836E+00 8.500E-01
56-BA-135 1.902E+01 5.820E-01 2.277E+00 6.108E+00 1.580E+00
56-BA-136 1.610E+01 6.500E-01 5.721E-01 6.928E+00 2.280E+00
56-BA-137 1.645E+01 5.640E-01 5.394E-01 4.905E+00 1.580E+00
56-BA-138 1.390E+01 7.200E-01 4.123E-01 7.233E+00 2.430E+00
---------------------------------------------------------------
Spin cutoff parameters were calculated as 0.146*sqrt(a)*a**(2/3).
In the CASTHY calculation, spin cutoff factors at 0 MeV were
assumed to be 5.625 for Ba-137 and 7.914 for Ba-138.
References
1) Aoki, T. et al.: Proc. Int. Conf. on Nuclear Data for Basic
and Applied Science, Santa Fe., Vol. 2, p.1627 (1985).
2) Kawai, M. et al.: J. Nucl. Sci. Technol., 29, 195 (1992).
3) Kikuchi, Y. et al.: JAERI-M 86-030 (1986).
4) Alves, R.N., et al.: Nucl. Phys., A134, 118 (1969).
5) Van de Vyver, R.E., Pattenden, N.J.: Nucl. Phys., A177, 393
(1971).
6) Musgrove, A.R. de L., et al.: Aust. J. Phys., 29, 157 (1976).
7) Kikuchi, Y.: JAERI-M 6248 (1975).
8) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. I,
Part A", Academic Press (1981).
9) Mizumoto, M.: J. Nucl. Sci. Technol., 25, 757 (1988).
10) Igarasi, S. and Fukahori, T.: JAERI 1321 (1991).
11) Musgrove, A.R. de L., et al.: Proc. Int. Conf. on Neutron
Physics and Nucl. Data for Reactors, Harwell 1978, 449.
12) Iijima, S. et al.: JAERI-M 87-025, p. 337 (1987).
13) Iijima, S. and Kawai, M.: J. Nucl. Sci. Technol., 20, 77
(1983).
14) Perey, F.G: Phys. Rev. 131, 745 (1963).
15) Huizenga, J.R. and Igo, G.: Nucl. Phys. 29, 462 (1962).
16) Lohr, J.M. and Haeberli, W.: Nucl. Phys. A232, 381 (1974).
17) Becchetti, F.D., Jr. and Greenlees, G.W.: Polarization
Phenomena in Nuclear Reactions ((Eds) H.H. Barshall and
W. Haeberli), p. 682, the University of Wisconsin Press.
(1971).
18) Gilbert, A. and Cameron, A.G.W.: Can. J. Phys., 43, 1446
(1965).
19) Iijima, S., et al.: J. Nucl. Sci. Technol. 21, 10 (1984).
20) Gruppelaar, H.: ECN-13 (1977).
21) Lederer, C.M., et al.: "Table of Isotopes, 7th Ed.", Wiley-
interscience Publication (1978).
22) Benzi, V. and Reffo, G.: CCDN-NW/10 (1969).
23) Kikuchi, K. and Kawai, M.: "Nuclear Matter and Nuclear
Reactions", North Holland (1968).
24) Wen Den Lu and Fink, R.W.: Phys. Rev., C4, 1173 (1971).
25) Forrest, R.A.: AERE-R 12419 (1986).
26) Mughabghab, S.F.: "Atlas of Neutron Resonances", Elsevier
(2006).
27) Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999)
[in Japanese].