63-Eu-151
63-EU-151 JAERI,JNDC EVAL-MAR89 T.ASAMI, JNDC FP ND W.G.
DIST-MAR02 REV2-SEP01 20010907
----JENDL-3.3 MATERIAL 6325
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
84-10 Evaluation for JENDL-2 was made by JNDC FPND W.G./1/
89-03 Evaluation for JENDL-3 was made by T.Asami(jaeri) and JNDC
FP NUCLEAR DATA W.G.
------------------------------------------------------------------
Data are the same as mat=3631 of JENDL-3 general purpose file/2/.
------------------------------------------------------------------
01-07 Compiled by K.Shibata for JENDL-3.3
***** modified parts for JENDL-3.3 ***********************
(1,451) Updated.
(3,251) Deleted.
(4,2) Transformation matrix deleted.
(5,16-91) INT=22
(12,16-107) Added.
(14,16-107) Added.
(15,16-107) Added.
************************************************************
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 0.0982 keV
For JENDL-2, resonance parameters were evaluated by Kikuchi
et al./3/ The parameters were adopted mainly from the data
measured by Rahn et al./4/ for the lowest 2 levels, the data
of Tassan et al./5/ were adopted. The average radiation width
of 0.093 eV/4/ was assumed for the levels whose radiation
width was not measured. A negative resonance was added at
-0.00361 eV so as to reproduce the capture cross section of
9200+-100 barns at 0.0253 eV/6/.
For JENDL-3, total spin J of some levels was estimated
with a random number method.
Unresolved resonance region : 0.0982 keV - 100 keV
The neutron strength functions S0, S1, S2 were based on the
compilation of Mughabghab/7/. The observed level spacing was
adjusted to reproduce the capture cross section measured by
Macklin and Young/8/. The effective scattering radius was
obtained from fitting to the calculated total cross section at
100 keV.
Typical values of the parameters at 70 keV:
S0 = 3.699e-4, S1 = 0.100e-4, S2 = 3.000e-4, Sg = 2230.e-4,
Gg = 0.091 eV, R = 6.870 fm.
calculated 2200-m/s cross sections and res. integrals (barns)
2200 m/s res. integ.
total 9201 -
elastic 3.207 -
capture 9198 3070
(n,alpha) 8.806e-06
mf = 3 Neutron cross sections
Below 100 keV, resonance parameters were given.
Above 100 keV, theoretical calculation was made by using the
optical and statistical model code casthy/9/ and the preequili-
brium and statistical model code gnash/10/. The omp's for
neutron are given in tables 1 and 2, which were determined so as
to reproduce the total cross section of natural Eu measured by
Foster and glasgow/11/. Those for charged particles are adopted
from Menet et al./12/ for proton and from Huizenga and Igo/13/
for alpha particle.
mt = 1 Total
Below 10 MeV, calculation with casthy was adopted. The
optical potential parameters listed in Table 1 were used.
Above 10 mev, the cross section was determined by eye-guiding
to the data of Foster and Glasgow/11/ for natural Eu.
mt = 2 Elastic scattering
Calculated as (total - sum of partial cross sections).
mt = 4, 51-60, 91 Inelastic scattering
Calculated with the casthy code. The level scheme used in the
calculations was taken from ref./14/
no level energy(MeV) spin-parity
g.s 0.0 5/2+
1 0.02150 7/2+
2 0.19620 11/2-
3 0.19650 3/2+
4 0.2432 7/2-
5 0.2604 5/2+
6 0.3070 7/2+
7 0.3075 5/2+
8 0.3498 9/2-
9 0.3536 7/2-
10 0.4160 7/2+
Levels above 0.420 MeV were assumed to be overlapping.
mt = 102 Capture
Below 2 MeV, cross section was determined by eye-guiding the
data measured by Macklin and Young/8/. Above 2 MeV, JENDL-2
data calculated with casthy was normalized to Macklin and
Young at 2 MeV. Direct and semi-direct capture cross sections
were added, which were estimated according to the procedure of
Benzi and Reffo/15/ and normalized to 1 milli-barn at 14 MeV.
mt=16, 17, 22, 28, 103, 107 (n,2n), (n,3n), (n,na), (n,np),
(n,p) and (n,a) cross sections
Calculated with the gnash code using the optical model
parameters in Table 2. The level scheme data were taken from
ref./14/. the calculated (n,2n) and (n,3n) cross sections
were modified on the basis of the experimental data of Frehaut
et al./16/ and Bayhurt/17/, respectively.
The (n,alpha) cross section in the resonance region was
calculated from resonance parameters, by assuming a mean alpha
width of 9.0e-11 ev so as to reproduce the thermal cross
section/7/. The cross section was averaged in suitable energy
intervals. Above 98.2 eV, the cross section was connected
smoothly to the gnash calculation.
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, the isotropic
distributions in the laboratory system were assumed.
mf = 5 Energy distributions of secondary neutrons
Energy distributions of secondary neutrons were calculated with
gnash.
mf = 12 Photon production multiplicities
mt=16, 17, 22, 28, 91, 103, 107
Calculated with gnash code /10/.
mt=102
Calculated with casthy code /9/.
mt=51-60
Transitioin probability arrays
mf = 14 Photon angular distributions
mt=16, 17, 22, 28, 51-60, 91, 102, 103, 107
Isotropic.
mf = 15 Continuous photon energy distributions
mt=16, 17, 22, 28, 91, 103, 107
Calculated with egnash code /10/.
mt=102
Calculated with casthy code /9/.
Table 1 Neutron optical potential parameters (for casthy)
V = 43.71 - 0.0566*En, Vso = 7.9 (MeV)
Ws = 7.696, Wv = 0.0 (MeV)
r = 1.270, rs = 1.440, rso = 1.280 (fm)
a = 0.60, b = 0.45, aso = 0.60 (fm)
Table 2 Neutron optical potential parameters (for gnash)
V = 43.71 - 0.05655*En, Vso = 0.0 (MeV)
Ws = 7.696, Wv = 0.0 (MeV)
r = 1.272, rs = 1.440, rso = 1.270 (fm)
a = 0.48, b = 0.45, aso = 0.48 (fm)
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) Shibata, K., et al.: JAERI 1319 (1990).
3) Kikuchi, Y. et al.: JAERI-M 86-030 (1986).
4) Rahn, F., et al.: Phys. Rev., C6, 251 (1972).
5) Tassan, S., et al.: Nucl. Sci., Eng., 10, 169 (1961).
6) Mughabghab, S.F., Garber, D.I.: "Neutron Cross Sections,
Vol.1, Rresonance Parameters", BNL 325, 3rd ed., Vol. 1,
(1973).
7) Mughabghab, S.F.: "Neutron Cross Sections, Vol. I, Part B",
Academic Press (1984).
8) Macklin, R.L. and Young, P.G.: Nucl. Sci. Eng., 95, 189(1987).
9) Igarasi, S.: J. Nucl. Sci. Technol., 12, 67 (1975).
10) Young, P.G. and Arthur, E.D.: LA-6947 (1977).
11) Foster Jr,.D.G. and Glasgow, D.W.: Phys. Rev., C3, 576 (1971).
12) Menet, J.J.H., et al.: Phys. Rev., C4, 1114 (1971).
13) Huizenga, J.R. and Igo, G.: Nucl. Phys. 29, 462 (1962).
14) ENSDF: Evaluated Nuclear Structure Data File (June 1987).
15) Benzi, V. and Reffo, G.: CCDN-NW/10 (1969).
16) Frehaut, J. et al.: Data (1980) in the EXFOR file.
17) Bayhurst, B.P. et al.: Phys. Rev., C12, 451 (1975).