68-Er-168 TIT EVAL-SEP00 A.K.M. HARUN-AR-RASHID+
DIST-MAY10 20091112
----JENDL-4.0 MATERIAL 6843
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
2000-09 Evaluation was performed by A.K.M.Harun-ar-Rashid (tit),
M.Igashira (tit), T.Ohsaki (tit), and K.Shibata (jaeri).
2001-02 Compiled by K.Shibata (jaeri).
2009-09 The unresolved resonance parameters were obtained by
K.Shibata. The data were compiled by K.Shibata.
mf=1 General information
mt=451 Descriptive data and dictionary
mf=2 Resonance parameters
mt=151 Resolved and unresolved resonance parameters
Resolved resonance region: below 3.5 keV
Resolved resonance parameters were taken from Ref. 1
The bound level at -163.0 eV has Gamma-n = 1.91395 eV and
Gamma-gamma = 0.088 eV. This choice gives the desired
value for the thermal capture cross section, 2.74+-0.08 b.
Values of Gamma-gamma not given in Ref.1 are set to 0.088
eV. 21 resonances [L=1] did not have values given for "J",
10 are assigned to J= 0.5 and the remaining 11 to J= 1.5 by
random method. The value for the scattering radius is
7.6fm, taken from Ref.2 with small change with in the given
error, so as to produce the close value of the thermal
neutron scattering cross section recommended by Mughabghab
[2]. Highest energy resonance included is 3304.1 eV.
No background cross sections were given.
Unresolved resonance region: 3.5 - 500 keV
The parameters were obtained by fitting to the calculated
total and capture cross sections. The unresolved resonance
parameters obtained should be used only for self-shielding
calculation.
Thermal cross sections and resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 1.1715E+01
Elastic 8.9854E+00
n,gamma 2.7296E+00 3.8311E+01
----------------------------------------------------------
mf=3 Neutron cross sections
mt= 1 Total cross section
Spherical optical model calculation was made by using
casthy code [3]. Parameters are as follows,
V = 48.2-0.25*E-16.0*(N-Z)/A , r0=1.18, a0=0.63
Ws = 7.84-0.51*E , rs=1.29, as=0.63
Vso= 6.0 , rso=1.26, aso=0.63
(energies in MeV, lengths in fm).
mt= 2 Elastic scattering cross section
The cross sections were obtained by subtracting a sum of
reaction cross sections from the total cross sections.
mt= 4,51,52,.,79,91 Inelastic scattering cross sections
Calculated by using egnash code [4,5].
The direct-process component was considered for mt=51
from dwba calculation by dwucky code. [4,6]
The level scheme is given as follows:
no. energy(MeV) spin-parity
g.s. 0.00000 0.0 +
1 0.07980 2.0 +
2 0.02461 4.0 +
3 0.54870 6.0 +
4 0.82180 2.0 +
5 0.89580 3.0 +
6 0.92830 8.0 +
7 0.99480 4.0 +
8 1.09400 4.0 -
9 1.11760 5.0 +
10 1.19300 5.0 -
11 1.21720 0.0 +
12 1.26390 6.0 +
13 1.27630 2.0 +
14 1.31150 6.0 -
15 1.35890 1.0 -
16 1.39680 10.0 +
17 1.40370 2.0 -
18 1.41110 4.0 +
19 1.42210 0.0 +
20 1.43150 3.0 -
21 1.43300 7.0 +
22 1.44900 7.0 -
23 1.49310 2.0 +
24 1.54160 3.0 -
25 1.54170 4.0 -
26 1.56950 2.0 -
27 1.57410 5.0 -
28 1.60590 8.0 -
29 1.61530 4.0 -
Levels above 1.620 MeV are assumed to be overlapping
mt= 16,17,22,28,32,103,104,105,107
(n,2n), (n,3n), (n,n'a), (n,n'p), (n,n'd)
(n,p), (n,d), (n,t), (n,a)
Calculated using egnash [4,5].
mt=102 Capture cross secton
The capture cross section is based on the statistical model
calculations. The measured data of Ref.7 were taken into
account. The direct and semidirect capture cross sections
were added above 2 MeV by using the quick gnash code [5,8].
mf=4 Angular distributions of secondary neutrons
mt=2
Calculated with the casthy code.
mt=16,17,22,28,32,
Assumed to be isotropic in the laboratory system.
mt=51,---,74,91
Calculated with the casthy code.
For mt=51, the dwba component was taken into account.
mf=5 Energy distributions of secondary neutrons
mt=16,17,22,28,32,91
Calculated with the egnash code.
mf=12 Photon production multiplicities
mt=16,17,22,28,51-74,91,102,103,104,107
Calculated with the egnash code.
mf=14 Photon angular distributions
mt=16,17,22,28,51-74,91,102,103,104,107
Assumed to be isotropic.
mf=15 Photon energy distributions
Calculated with the egnash code.
mt=16,17,22,28,91,102,103,104,107
Calculated with the egnash code.
For mt=102, the measured data [9] are included at 45
and 550 keV.
References
1. Landolt-Boernstein New Series I/16B (Aug 1998).
2. S. F. Mughabghab: "Neutron Cross Sections: Vol. 1,
Neutron Resonance Parameters and Thermal Cross Sections,
Part B: Z=61-100," Academic press (1984).
3. S. Igarasi, T. Fukahori: JAERI 1321 (1991).
4. N. Yamamuro: JAERI-M 90-006 (1990).
5. P.G. Young et al.: LA-12343-MS, UC-413 (1992).
6. P.D. Kunz: Program DWUCK4, Computational Nuclear Physics 2:
Nuclear Reaction, edited by K. Langanke et al., published by
Springer-Verlag (1992).
7. A.K.M. Harun-ar-Rashid et al.: JAERI-CONF 2000-005, pp.131,
(2000).
8. N. Yamano: Private communication.
9. M. Igashira: Private communication (2001).