56-Ba-138
56-Ba-138 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.
DIST-MAY10 20091217
----JENDL-4.0 MATERIAL 5649
-----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
(3,102) Re-normalization
(3,2), (3,4), (3,51-91) and angular distributions
Small effects of the re-normalization of
capture cross section. ( < 0.3% )
***********************************************************
10-03 JENDL-4.0 was made.
Resoloved resonance parameters were evaluated by K.Shibata.
Compiled by S.Kunieda
***** modified parts for JENDL-4.0 ********************
(1,451) Updated.
(2,151) Updated.
(3,1) Re-calculated from partial cross sections.
(3,4) Re-calculated from partial cross sections.
***********************************************************
mf = 1 General information
mt=451 Comments and dictionary
mf = 2 Resonance parameters
mt=151 Resolved and unresolved resonance parameters
Resolved resonance parameters for MLBW formula (below 100 keV)
For JENDL-2, evaluation was made by Kikuchi /3/ mainly on
the basis of the data measured by Musgrove et al./4/ up to 92
keV. Above 100 keV, neutron widths were adopted from Bilpuch
et al./5/ Average capture widths were assumed to be 0.055+-
0.020 eV for s-wave resonances and 0.045+-0.020 eV for p-wave
ones, and to be 0.095 eV in the energy range above 100 keV. A
negative resonance was added at -6.22 keV so as to reproduce
the capture cross section of 0.360+-0.036 barns at 0.0253
eV/6/.
For JENDL-3, 10 resonances were newly asigned by taking the
experimental data by Mizumoto/7/ in the energy range from 648
eV to 63.12 keV. Total spin J of some resonances was tenta-
tively estimated with a random number method
*************************************************************
In JENDL-4, the data above 100 keV were replaced with the
ones obtained by Brusegan et al./28/ The radiation widths
of 95 meV and 47 meV were assumed for s- and p-wave
resonances, respectively. The parameters for the negative
resonance were re-adjusted so as to reproduce the thermal
capture cross section recommended by Mughabghab./29/
*************************************************************
No unresolved resonance region
Thermal cross sections & resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 6.44545E+00
Elastic 6.04108E+00
n,gamma 4.04376E-01 2.83528E-01
----------------------------------------------------------
(*) 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/8/, by taking account of
competing reactions, of which cross sections were calculated
with PEGASUS/9/ 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 Ba-nat. Total
cross section by changing Ws and rso of Iijima-Kawai potential
/10/. The OMP's for charged particles are as follows:
proton = Perey/11/
alpha = Huizenga and Igo/12/
deuteron = Lohr and Haeberli/13/
helium-3 and triton = Becchetti and Greenlees/14/
Parameters for the composite level density formula of Gilbert
and Cameron/15/ were evaluated by Iijima et al./16/ 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
/17/.
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./18/.
no. energy(MeV) spin-parity dwba cal.
gr. 0.0 0 +
1 1.4359 2 + *
2 1.8987 4 +
3 2.0907 6 +
4 2.1896 2 +
5 2.2032 6 +
6 2.2180 2 +
7 2.3077 4 +
8 2.4156 5 +
9 2.4457 3 +
10 2.5832 1 +
11 2.5840 4 +
12 2.6396 2 +
13 2.7795 4 +
14 2.8517 3 +
15 2.8810 3 - *
16 2.9315 1 +
17 2.9912 3 +
18 3.0500 2 +
19 3.1560 4 +
Levels above 3.164 MeV were assumed to be overlapping.
For the levels with an asterisk, the contribution of direct
inelastic scattering cross sections was calculated by the
DWUCK-4 code/19/. Deformation parameters (beta2 = 0.0925 and
beta3 = 0.118) were based on the data compiled by Raman et
al./20/ and Spear/21/, respectively.
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 (2.54e-06) was adjusted to the
capture cross section of 2.7 milli-barns at 700 keV so as to
reproduce the cross section measured by Johnsrud et al./23/
and Stavisskij and Tolstikov/24/
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 =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 (= 144.6) was estimated by the
formula derived from Kikuchi-Kawai's formalism/25/ 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) 1750.00 mb (systematics of Wen Den Lu+/26/)
(n,p) 2.80 mb (measured by Ikeda+/27/)
(n,alpha) 2.10 mb (measured by Ikeda+)
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. Contribution of direct inelastic
scattering was calculated with DWUCK-4. For other reactions,
isotropic distributions 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 to 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-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
54-XE-137 1.550E+01 5.565E-01 7.470E-01 4.010E+00 1.120E+00
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
55-CS-138 1.470E+01 5.737E-01 4.715E+00 2.858E+00 0.0
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
56-BA-139 2.022E+01 4.800E-01 5.326E-01 4.629E+00 1.580E+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 7.914 for Ba-138 and 5.0 for Ba-139.
References
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5) Bilpuch, E.G., et al.: Ann. Phys., 14, 387 (1961).
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Part A", Academic Press (1981).
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(1983).
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14) Becchetti, F.D., Jr. and Greenlees, G.W.: Polarization
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(1987)
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(1961). EXFOR 40642004.
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Reactions", North Holland (1968).
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28) Brusegan, A. et al.: 94 Gatlinburg, p.227 (1994).
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(2006).