35-Br- 81 JAEA EVAL-AUG09 K.Shibata, A.Ichihara, S.Kunieda
DIST-MAY10 20091118
----JENDL-4.0 MATERIAL 3531
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
History
09-08 Evaluated by K. Shibata, JAEA.
09-10 Compiled by K. Shibata.
MF= 1 General information
MT=451 Descriptive data and directory
MF= 2 Resonance parameters
MT=151 Resolved and unresolved resonance parameters
Resolved resonance region (mlbw formula) : below 13 keV
resonance energies for the 304 levels and for the remaining
3 levels were based on the measurements by Macklin/1/ and
by Ohkubo et al./2/, respectively. Neutron and radiation
widths were determined by different methods according to the
following three conditions, respectively.
1) In cases where total width and neutron capture area
measured by macklin were given for a resonance level, the
neutron and radiation widths were simultaneously obtained by
solving a quadratic equation.
2) In cases where neutron capture area measured by macklin
and g*(reduced neutron width) measured by Ohkubo et al. were
available, the radiation widths were derived from the both
data.
3) In cases where only neutron capture area by Macklin was
available, or g*(neutron width) by Ohkubo et al. was smaller
than neutron capture area by Macklin for a resonance level,
the average radiation width of 279 meV given by Macklin was
adopted. The neutron width was derived from this average
radiation width and the neutron capture area. In addition,
if the value of g*(averaged radiation width) was smaller
than neutron capture area for some resonance levels, the
average radiation width was increased depending on the value
of neutron capture area, so as to satisfy the following
condition:
g*(average radiation width) > neutron capture area.
Total spin J of some resonances was tentatively estimated
with a random number method. Neutron orbital angular
momentum L was assumed to be 0 for all resonance levels.
Scattering radius was taken from the graph (fig. 1, Part A)
given by Mughabghab et al./3/ A negative resonance was
added so as to reproduce the thermal capture cross section
given by Mughabghab et al.
In JENDL-4, the radiation width of a negative resonance was
changed to 123 meV.
Unresolved resonance region: 13 keV - 700 keV
The parameters were obtained by fitting to the total and
capture cross sections calculated from POD /4/. The
unresolved parameters 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 5.9956E+00
Elastic 3.6394E+00
n,gamma 2.3561E+00 4.6622E+01
----------------------------------------------------------
(*) Integrated from 0.5 eV to 10 MeV.
MF= 3 Neutron cross sections
MT= 1 Total cross section
Calculated with POD code /4/.
MT= 2 Elastic scattering cross section
Obtained by subtracting non-elastic cross sections from total
cross sections.
MT= 3 Non-elastic cross section
Sum of partial non-elastic cross sections.
MT= 4,51-91 (n,n') cross section
Calculated with POD code /4/.
MT= 16 (n,2n) cross section
Calculated with POD code /4/.
MT= 17 (n,3n) cross section
Calculated with POD code /4/.
MT= 22 (n,na) cross section
Calculated with POD code /4/.
MT= 28 (n,np) cross section
Calculated with POD code /4/.
MT= 32 (n,nd) cross section
Calculated with POD code /4/.
MT=102 Capture cross section
Calculated with POD code /4/.
MT=103 (n,p) cross section
Calculated with POD code /4/.
MT=104 (n,d) cross section
Calculated with POD code /4/.
MT=105 (n,t) cross section
Calculated with POD code /4/.
MT=106 (n,He3) cross section
Calculated with POD code /4/.
MT=107 (n,a) cross section
Calculated with POD code /4/.
MT=203 (n,xp) cross section
Calculated with POD code /4/.
MT=204 (n,xd) cross section
Calculated with POD code /4/.
MT=205 (n,xt) cross section
Calculated with POD code /4/.
MT=206 (n,xHe3) cross section
Calculated with POD code /4/.
MT=207 (n,xa) cross section
Calculated with POD code /4/.
MF= 4 Angular distributions of emitted neutrons
MT= 2 Elastic scattering
Calculated with POD code /4/.
MF= 6 Energy-angle distributions of emitted particles
MT= 16 (n,2n) reaction
Neutron spectra calculated with POD/4/.
MT= 17 (n,3n) reaction
Neutron spectra calculated with POD/4/.
MT= 22 (n,na) reaction
Neutron spectra calculated with POD/4/.
MT= 28 (n,np) reaction
Neutron spectra calculated with POD/4/.
MT= 32 (n,nd) reaction
Neutron spectra calculated with POD/4/.
MT= 51 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 52 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 53 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 54 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 55 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 56 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 57 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 58 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 59 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 60 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 61 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 62 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 63 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 64 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 65 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 66 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 67 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 68 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 69 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 70 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 71 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 72 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 73 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 74 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 75 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 76 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 77 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 78 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 79 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 80 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 81 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 82 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 83 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 84 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 85 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 86 (n,n') reaction
Neutron angular distributions calculated with POD/4/.
MT= 91 (n,n') reaction
Neutron spectra calculated with POD/4/.
MT= 203 (n,xp) reaction
Proton spectra calculated with POD/4/.
MT= 204 (n,xd) reaction
Deuteron spectra calculated with POD/4/.
MT= 205 (n,xt) reaction
Triton spectra calculated with POD/4/.
MT= 206 (n,xHe3) reaction
He3 spectra calculated with POD/4/.
MT= 207 (n,xa) reaction
Alpha spectra calculated with POD/4/.
MF=12 Gamma-ray multiplicities
MT= 3 Non-elastic gamma emission
Calculated with POD code /4/.
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 with POD code /4/.
***************************************************************
* Nuclear Model Calculations with POD Code /4/ *
***************************************************************
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 preequilibrim 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.
2. Optical model parameters
Neutrons:
Coupled-channel optical model parameters /5/
Protons:
Koning and Delaroche /6/
Deuterons:
Lohr and Haeberli /7/
Tritons:
Becchetti and Greenlees /8/
He-3:
Becchetti and Greenlees /8/
Alphas:
Lemos /9/ potentials modified by Arthur and Young /10/
3. Level scheme of Br- 81
-------------------------
No. Ex(MeV) J PI
-------------------------
0 0.00000 3/2 -
1 0.27599 5/2 -
2 0.53620 9/2 +
3 0.53820 3/2 -
4 0.56603 3/2 -
5 0.64990 3/2 -
6 0.76715 5/2 -
7 0.78940 5/2 +
8 0.82829 3/2 -
9 0.83677 7/2 -
10 0.90600 5/2 -
11 0.97500 3/2 -
12 1.02370 5/2 -
13 1.07600 1/2 -
14 1.10530 1/2 -
15 1.17000 1/2 -
16 1.17680 13/2 +
17 1.18990 7/2 -
18 1.23788 3/2 +
19 1.26600 7/2 -
20 1.26640 9/2 -
21 1.30000 5/2 -
22 1.32300 5/2 -
23 1.32740 3/2 +
24 1.34980 5/2 +
25 1.37150 7/2 +
26 1.40100 3/2 -
27 1.48180 7/2 -
28 1.51290 3/2 -
29 1.52230 11/2 +
30 1.53590 3/2 -
31 1.53600 3/2 +
32 1.54160 9/2 +
33 1.54300 5/2 +
34 1.54320 3/2 -
35 1.58700 3/2 -
36 1.58740 1/2 +
-------------------------
Levels above 1.59740 MeV are assumed to be continuous.
4. Level density parameters
Energy-dependent parameters of Mengoni-Nakajima /11/ were used
----------------------------------------------------------
Nuclei a* Pair Esh T E0 Ematch Elv_max
1/MeV MeV MeV MeV MeV MeV MeV
----------------------------------------------------------
Br- 82 10.599 0.000 2.092 0.832 -2.117 6.154 1.261
Br- 81 10.293 1.333 2.879 0.880 -1.411 8.480 1.587
Br- 80 10.191 0.000 3.385 0.903 -3.155 7.747 0.771
Br- 79 10.079 1.350 3.698 0.897 -1.795 9.044 1.513
Se- 81 10.589 1.333 1.999 0.755 -0.063 6.204 2.253
Se- 80 10.645 2.683 2.442 0.815 0.539 8.768 3.226
Se- 79 10.473 1.350 3.245 0.875 -1.656 8.768 0.729
As- 79 10.079 1.350 2.572 0.864 -0.976 7.886 1.518
As- 78 10.399 0.000 2.885 0.736 -1.468 4.841 0.536
As- 77 9.864 1.368 3.386 0.907 -1.622 8.902 1.676
----------------------------------------------------------
5. Gamma-ray strength functions
M1, E2: Standard Lorentzian (SLO)
E1 : Generalized Lorentzian (GLO) /12/
6. Preequilibrium process
Preequilibrium is on for n, p, d, t, He-3, and alpha.
Preequilibrium capture is on.
References
1) Macklin, R.L.: Nucl. Sci. Eng., 99, 133 (1988).
2) Ohkubo, M. et al.: J. Nucl. Sci. Technol. 18, 745 (1981).
3) Mughabghab, S.F. et al.: "Neutron Cross Sections, Vol. I,
Part A", Academic Press (1981).
4) A.Ichihara et al., JAEA-Data/Code 2007-012 (2007).
5) S.Kunieda et al., J. Nucl. Sci. Technol. 44, 838 (2007).
6) A.J.Koning, J.P.Delaroche, Nucl. Phys. A713, 231 (2003).
7) J.M.Lohr, W.Haeberli, Nucl. Phys. A232, 381 (1974).
8) F.D.Becchetti,Jr., G.W.Greenlees, "Polarization
Phenomena in Nuclear Reactions," p.682, The University
of Wisconsin Press (1971).
9) O.F.Lemos, Orsay Report, Series A, No.136 (1972).
10) E.D.Arthur, P.G.Young, LA-8626-MS (1980).
11) A.Mengoni, Y.Nakajima, J. Nucl. Sci. Technol. 31, 151
(1994).
12) J.Kopecky, M.Uhl, Nucl. Sci. Eng. 41, 1941 (1990).