93-Np-235 JAERI EVAL-MAR95 T.Nakagawa
DIST-MAR02 20001004
----JENDL-3.3 MATERIAL 9340
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
95-02 New evaluation was made by T.Nakagawa. STAPRE calculation
was performed by Konshin /Ko95/.
00-10 Compiled by T.Nakagawa.
MF=1 General information
MT=451 Descriptive data
MT=452 Number of neutrons per fission
Sum of MT=455 and 456.
MT=455 Delayed neutrons per fission
Tuttle's systematics /Tu79/ was adopted.
MT=456 Prompt neutrons per fission
Obtained from Howerton's sytematics /Ho77/.
MF=2 Resonance parameters
MT=151
No resonance parameters were given.
Thermal cross sections and resonance integral (barns)
0.0253 eV resonance int.
Total 181.4 -
Elastic 11.4 -
Fission 20 46.6
Capture 150 851
MF=3 Neutron cross sections
Below 0.4 eV
The capture is based on the data of Landrum et al./La72/
The elastic scattering cross section of 11.4 b is the shape
elastic scattering calculated with optical model code
CASTHY/Ig91/. The fission cross section is assumed to be
similar to that of Pu-238.
Above 0.4 eV
Three codes of CASTHY/Ig91/, ECIS/Ra00/ and STAPRE/Uh76/
were used.
Parameters (MeV, fm) of deformed potential/Ko93/ for ECIS:
V = 46.03 - 0.3*E
W-d = 3.05 + 0.4*E 0 =< E =< 10 MeV
= 7.05 - 0.082*(E-10) 10 < E <=20 MeV
W-v = 8.0/(1+exp(-(E-50)/10))
V-so= 6.2
r-r = 1.26 a-r = 0.63
r-d = 1.26 a-d = 0.52
r-so= 1.12 a-so= 0.47
beta-2 = 0.204 beta-4 =0.051
The spherical potential parameters/Ig85/ used in CASTHY:
V = 45.036 - 0.3*E, r-r = 1.256, a-r = 0.626
W-d = 4.115 + 0.4*E, r-d = 1.260, a-d = 0.555+0.0045*E
V-so= 7.5, r-so= 1.256, a-so= 0.626
Level density parameters used in CASTHY:
a(1/MeV) T(MeV) delta(MeV) E-x(MeV) spin-cutoff
Np-235 30.4 0.38 0.7828 3.929 30.66
Np-236 28.0 0.35 0.0 2.258 20.50
STAPRE calculation is described in Ko95.
MT=1 Total
Calculated with CASTHY.
MT=2 Elastic scattering
Calculated as the (total) - (sum of partial) cross sections.
MT=4, 51-91 Inelastic scattering
Compound process was calculated with CASTHY, and direct one
with ECIS.
Level scheme/Sc93/:
Energy (keV) Spin-parity direct-component
0.0 5/2 +
34.23 7/2 + *
49.1 5/2 -
79.1 9/2 + *
91.6 7/2 -
133. 11/2 + *
146.8 9/2 -
200. 13/2 + *
352. 3/2 -
371. 1/2 -
408. 7/2 -
441. 5/2 -
520. 11/2 -
565. 3/2 -
602. 5/2 -
644. 7/2 -
700. 9/2 -
Levels above 750 keV were assumed to be overlapping.
The direct process was calculated with ECIS for the levels
marked with *, and the compound process with CASTHY.
MT=16,17 (n,2n) and (n,3n) reactions
Calculated with STAPRE.
MT=18 Fission
Based on the calculation with STAPRE and systematics of the
fission cross section shape.
MT=102 capture
Calculated with CASTHY. The direct and semi-direct cross
section was calculated with DSD /Ka99/.
MF=4 Angular distributions of secondary neutrons
MT=2 Elastic scattering
Calculated with ECIS.
MT=16,17, 18 (n,2n), (n,3n) and Fission
Assumed to be isotopic in the laboratory system.
MT=51-91 Inelastic scattering
Calculated with CASTHY and ECIS.
MF=5 Energy distributions of secondary neutrons
MT=16, 17, 91
Calculated with EGNASH /Ya90/.
MT=18
Evaporation spectrum with nuclear temperature obtained from
the systematics of Smith et al. /Sm79/ and Howerton and Doyas
/Ho71/. The ratios of multi-chance fission to total were
estimated from the STAPRE calculation/Ko95/.
References
Ho71) R.J. Howerton and R.J. Doyas: Nucl. Sci. Eng., 46, 414
(1971).
Ho77) R.J. Howerton: Nucl. Sci. Eng., 62, 438 (1977).
Ig85) A.V. Ignatyuk, et al.: Sov. J. Nucl. Phys. 42, 360 (1985).
Ig91) S. Igarasi and T. Fukahori: JAERI 1321 (1991).
Ka99) T. Kawano: private communication (1999).
Ko93) V.A. Konshin, et al.: Proc. Workshop on Computation and
Analysis of Nuclear Data Relevant to Nuclear Energy and
Safety, Trieste, Italy, 10 Feb. - 13 Mar 1992, World
Scientific, p.775 (1993).
Ko95) V.A. Konshin: JAERI-Research 95-010 (1995).
La72) J.H. Landrum, et al.: UCRL-51263 (1972).
Ra00) J. Raynal: available from OECD NEA Data Bank.
Sc93) M.R. Schmorak: Nucl. Data Sheets, 69, 375 (1993).
Sm79) A. Smith, et al.: ANL/NDM-50 (1979).
Tu79) R.J. Tuttle: INDC(NDS)-107/G+Special, p.29 (1979).
Uh76) M. Uhl and B. Stromaier: IRK-76/10 (1976).
Ya90) N. Yamamuro: JAERI-M 90-006 (1990).