70-Yb-176 JAEA EVAL-FEB10 S.Kunieda, A.Ichihara, K.Shibata+
DIST-MAY10 20100222
----JENDL-4.0 MATERIAL 7049
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
10-02 New evaluation was done (compiled by S. Kunieda).
MF= 1 General information
MT=451 Descriptive data and directory
MF= 2 Resonance parameters
MT=151 Resolved and unresolved resonance parameters
- Resolved resonance region: below 5.0 keV
The parameters (MLBW formula) were taken from the
compilation of Mughabghab /1/.
- Unresolved resonance region: 5.0 keV - 250 keV
The parameters were obtained by fitting to the total and
capture cross sections calculated by the POD code /2/.
The ASREP code /3/ was employed in this evaluation.
The unresolved parameters should be used only for
self-shielding calculation.
Thermal cross sections & resonance integrals at 300 K
----------------------------------------------------------
0.0253 eV res. integ. (*)
(barns) (barns)
----------------------------------------------------------
Total 1.16948E+01
Elastic 8.87143E+00
n,gamma 2.82339E+00 6.97643E+00
----------------------------------------------------------
(*) Integrated from 0.5 eV to 10 MeV.
MF= 3 Neutron cross sections
MT= 1 Total cross section
Sum of partial cross sections.
MT= 2 Elastic scattering cross section
The OPTMAN /4/ & POD calculations /2/.
MT= 3 Non-elastic cross section
Sum of partial non-elastic cross sections.
MT= 4,51-91 (n,n') cross section
The OPTMAN /4/ & POD calculations /2/.
MT= 16 (n,2n) cross section
MT= 17 (n,3n) cross section
MT= 22 (n,na) cross section
MT= 28 (n,np) cross section
MT= 32 (n,nd) cross section
Calculated by the POD code /2/.
MT=102 Capture cross section
Calculated by the POD code /2/. Gamma-ray strength
function was normalized to fit the experimental cross
sections measured by Wisshak et al /5/.
MT=103 (n,p) cross section
MT=104 (n,d) cross section
MT=105 (n,t) cross section
MT=106 (n,He3) cross section
MT=107 (n,a) cross section
Calculated by the POD code /2/.
MT=203 (n,xp) cross section
Sum of (n,np) and (n,p)
MT=204 (n,xd) cross section
Sum of (n,nd) and (n,d)
MT=205 (n,xt) cross section
MT=206 (n,xHe3) cross section
Calculated by the POD code /2/.
MT=207 (n,xa) cross section
Sum of (n,na) and (n,a)
MF= 4 Angular distributions of emitted neutrons
MT= 2 Elastic scattering
The OPTMAN /4/ & POD calculations /2/.
MF= 6 Energy-angle distributions of emitted particles
MT= 16 (n,2n) reaction
MT= 17 (n,3n) reaction
MT= 22 (n,na) reaction
MT= 28 (n,np) reaction
MT= 32 (n,nd) reaction
Neutron spectra calculated by the POD code /2/.
MT= 51-90 (n,n') reaction
Neutron angular distributions calculated by
OPTMAN /4/ & POD /2/.
MT= 91 (n,n') reaction
Neutron spectra calculated by the POD code /2/.
MT= 203 (n,xp) reaction
MT= 204 (n,xd) reaction
MT= 205 (n,xt) reaction
MT= 206 (n,xHe3) reaction
MT= 207 (n,xa) reaction
Light-ion spectra calculated by the POD code /6/.
MF=12 Gamma-ray multiplicities
MT= 3 Non-elastic gamma emission
Calculated by the POD code /2/.
MF=14 Gamma-ray angular distributions
MT= 3 Non-elastic gamma emission
Assumed to be isotropic.
MF=15 Gamma-ray spectra
MT= 3 Non-elastic gamma emission
Calculated by the POD code /2/.
***************************************************************
* Nuclear Model Calculations with POD Code /2/ *
***************************************************************
1. Theoretical models
The POD code is based on the spherical optical model, the
distorted-wave Born approximaiton (DWBA), one-component exciton
preequilibrium model, and the Hauser-Feshbach-Moldauer statis-
tical model. With the preequilibrium model, semi-empirical
pickup and knockout process can be taken into account for
composite-particle emission. The gamma-ray emission from the
compound nucleus can be calculated within the framework of the
exciton model. The code is capable of reading in particle
transmission coefficients calculated by separate spherical or
coupled-channel optical model code. In this evaluation, the OPTMAN
/4/ code was employed for neutrons, while the ECIS code
/6/ was adopted for charged particles.
2. Optical model & parameters
Neutrons:
Model: Coupled-channel model based on the rigid-rotor model
OMP : Coupled-channel optical potential /7/
Deformation parameters were taken from FRDM /8/.
Protons:
Model: Spherical
OMP : Koning and Delaroche /9/
Deuterons:
Model: Spherical
OMP : Bojowald et al. /10/
Tritons:
Mode: Spherical
OMP : Becchetti and Greenlees /11/
He-3:
Model: Spherical
OMP : Becchetti and Greenlees /11/
Alphas:
Model: Spherical
OMP : A simplified folding model potential /12/
(The nucleon OMP was taken form Ref./7/.)
3. Level scheme of Yb-176
------------------------------------
No. Ex(MeV) J PI CC
------------------------------------
0 0.00000 0 + *
1 0.08213 2 + *
2 0.27170 4 + *
3 0.56470 6 + *
4 0.95400 8 + *
5 1.05000 8 -
6 1.08820 0 +
7 1.13200 3 +
8 1.19340 3 -
9 1.26090 2 +
10 1.28340 2 +
11 1.34110 2 +
12 1.43100 10 +
13 1.43170 4 -
-------------------------
Levels above 1.44170 MeV are assumed to be continuous.
4. Level density parameters
Energy-dependent parameters of Mengoni-Nakajima /13/ were used
----------------------------------------------------------
Nuclei a* Pair Esh T E0 Ematch Elv_max
1/MeV MeV MeV MeV MeV MeV MeV
----------------------------------------------------------
Yb-177 20.576 0.902 1.393 0.514 -0.787 5.416 0.526
Yb-176 20.767 1.809 1.620 0.504 0.128 6.258 1.432
Yb-175 19.992 0.907 1.317 0.517 -0.669 5.299 0.872
Yb-174 20.061 1.819 1.463 0.541 -0.106 6.753 1.926
Tm-176 20.617 0.000 1.514 0.541 -2.085 5.130 -
Tm-175 19.828 0.907 1.572 0.490 -0.388 4.810 0.532
Tm-174 20.417 0.000 1.186 0.574 -2.400 5.682 -
Er-174 20.564 1.819 1.826 0.508 0.071 6.367 -
Er-173 21.018 0.912 1.560 0.495 -0.711 5.236 -
Er-172 20.361 1.830 1.668 0.479 0.504 5.706 0.961
----------------------------------------------------------
5. Gamma-ray strength functions
M1, E2: Standard Lorentzian (SLO)
E1 : Generalized Lorentzian (GLO) /14/
6. Preequilibrium process
Preequilibrium is on for n, p, d, t, He-3, and alpha.
Preequilibrium capture is on.
References
1) S.F.Mughabghab, "Atlas of Neutron Resonances",
Elsevier (2006).
2) A.Ichihara et al., JAEA-Data/Code 2007-012 (2007).
3) Y.Kikuchi et al., JAERI-Data/Code 99-025 (1999)
[in Japanese].
4) E.Soukhovitski et al., JAERI-Data/Code 2005-002 (2005).
5) K.Wisshak et al., Phys. Rev. C61, 065801 (2000).
6) J.Raynal, CEA Saclay report, CEA-N-2772 (1994).
7) S.Kunieda et al., J. Nucl. Sci. Technol. 44, 838 (2007).
8) P.Moller et al., At. Data and Nucl. Data Tables 59, 185
(1995).
9) A.J.Koning, J.P.Delaroche, Nucl. Phys. A713, 231 (2003).
10) Bojowald et al., Phys. Rev. C 38, 1153 (1988).
11) F.D.Becchetti,Jr., G.W.Greenlees, "Polarization
Phenomena in Nuclear Reactions," p.682, The University
of Wisconsin Press (1971).
12) D.G.Madland, NEANDC-245 (1988), p. 103.
13) A.Mengoni, Y.Nakajima, J. Nucl. Sci. Technol. 31, 151
(1994).
14) M.Brink, Ph.D thesis, Oxford University, 1955.