95-Am-242mMINSK,BYEL EVAL-DEC96 V.M. Maslov et al.
INDC(BLR)-007 DIST-MAR02 REV2-FEB02 20020218
----JENDL-3.3 MATERIAL 9547
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
80-03 New evaluation was made by T.Nakagawa and S.Igarasi/Na80/
88-03 Reevaluation for JENDL-3 was made by T.Nakagawa /Na89/
00-04 JENDL-3.3 was compiled by T.Nakagawa
Evaluated data of Maslov et al. /Ma97/ were extensively
adopted.
02-02 Capture cross section ( > 5 MeV) was modified.
***** Modified parts from JENDL-3.2 *******************
All data except (3,18)
*******************************************************
=================================================================
Description on modified parts from Maslov's evaluation.
=================================================================
MF=1 General information
MT=452 Total number of neutrons per fission
Sum of MT=455 and 456.
MT=455 Delayed neutrons
Nu-d values were replaced with almost the same value as
JENDL-3.2 which were estimated from Tuttle's systematics
/Tu79/.
MF=2 Resonance Rapameters
MT=151
Unresolved resonance parameters
The level spacing was modified to keep consistency with
that of L=0 and J=4.5. The neutron width was also modified
with the same factor as the level spacing. Interpolation
of cross sections was changed to 5 (log-log).
Calculated Thermal cross sections and Resonance integral
at 0.0253 eV (b) Res. Integ. (b)
Total 7624.9 -
Elastic 5.25 -
Fission 6390.4 1540
Capture 1229.3 240
MF=3 Neutron Cross Sections
MT=2 elastic
Calculated as Total - partial cross sections.
MT=18 Fission
Above 27.2832 keV, JENDL-3.2 was adopted because JENDL-3.2 was
in better agreement with experimental data than Maslov's
evaluation.
NOTE: The data of MT's=19, 20 and 21 calculated by Maslov et
al. /Ma97/ were not adopted.
MF=102 Capture cross section
Above about 5 MeV, the direct and semi-direct capture cross
section was calculated with DSD code /Ka99/.
MF=5 Energy Distributions of Secondary Neutrons
MT=16, 17, 91
At the threshold energies, the same shape of distributions at
the second incident energy was assumed. Interpolation was
replaced with 22.
MT=455
Results of summation calculation made by Brady and England
/Br89/ were adopted.
Other parts are the same as Maslov's evaluation.
References
Br89) Brady M.C. and England T.R.: Nucl. Sci. Eng., 103, 129
(1989).
Ka99) Kawano T.: private communication (1999).
Ma97) Maslov V.M. et al.: INDC(BLR)-007 (1997).
Na80) Nakagawa T. and Igarasi S.: JAERI-M 8903 (1990).
Na89) Nakagawa T.: JAERI-M 89-008 (1990).
Tu79) Tuttle R.J.: INDC(NDS)-107/G+Special, 29 (1979).
========== Description given in Maslov's data ===================
95-Am-242M MINSK BYEL EVAL-DEC96
DIST-DEC96
V.M. MASLOV, E.Sh. SUKHOVITSKIJ,
Yu.V. PORODZINSKIJ, G.B. MOROGOVSKIJ
STATUS
EVALUATION WAS MADE UNDER THE PROJECT AGREEMENT CIS-03-95
WITH INTERNATIONAL SCIENCE AND TECHNOLOGY CENTER (MOSCOW).
FINANCING PARTY OF THE ISTC FOR THE PROJECT IS JAPAN.
EVALUATION WAS REQUESTED BY Y.KIKUCHI (JAERI, TOKAI)
DOCUMENTED IN INDC(BLR)-007, 1997.
MF=1 GENERAL INFORMATION
MT=451 COMMENTS AND DICTIONARY
MT=452 TOTAL NUMBER OF NEUTRONS PER FISSION
SUM OF MT=455 AND MT=456.
MT=455 DELAYED NEUTRON DATA
NUMBER OF DELAYED NEUTRONS AND
DECAY CONSTANTS FROM BRADY ET AL./1/
MT=456 NUMBER OF PROMPT NEUTRONS PER FISSION
MADLAND-NIX MODEL CALCULATIONS /2/ FITTED TO
THE MEASURED DATA OF HOWE ET AL./3/
ABOVE EMISSIVE FISSION THRESHOLD
SUPERPOSITION OF NEUTRON EMISSION
IN (N,XNF) REACTIONS /4/ AND PROMPT FISSION
NEUTRONS IS EMPLOYED.
MF=2 RESONANCE PARAMETERS
MT=151 RESONANCE PARAMETERS (MLBW)
RESOLVED RESONANCE REGION : 1.0E-5 - 43 EV
PARAMETERS FOR BREIT-WIGNER FORMULA ARE BASED UPON
THE FISSION CROSS SECTION MEASUREMENTS OF BROWNE ET AL.
/5/
CALCULATED 2200 M/S CROSS SECTIONS AND RESONANCE
INTEGRALS ARE:
2200 M/SEC RES.INTEG.
TOTAL 7624.69 b -
ELASTIC 5.2526 b -
FISSION 6390.21 b 1543.91
CAPTURE 1229.23 b 239.610
UNRESOLVED RESONANCE REGION :
ENERGY INDEPENDENT PARAMETERS:
R=9.1677 FM FROM OPTICAL MODEL CALCULATIONS
S1=2.020*10-4 FROM OPTICAL MODEL CALCULATIONS
S2=1.540*10-4 FROM OPTICAL MODEL CALCULATIONS
ENERGY DEPENDENT PARAMETERS:
S0-DECREASES FROM 1.215-4(0.15KEV) TO 1.15-4(27.28KEV),
BELOW 0.1 KEV FLUCTUATES TO FIT FISSION CROSS SECTION.
D - SPIN DEPENDENT, NORMALIZED TO =0.271 EV
WITH ACCOUNT OF LEVEL MISSING /6/.
WF -SPIN DEPENDENT AS DEFINED BY THE TRANSITION STATE
SPECTRA AT INNER AND OUTER BARRIER HUMPS, NORMALIZED
TO =0.395 mEV TO FIT UNRESOLVED RESONANCE REGION
EXPERIMENTAL FISSION DATA /5/.
WG - FROM CASCADE MODEL WITH ACCOUNT OF FISSION AND
NEUTRON EMISSION COMPETITION, SPIN DEPENDENT. NORMA-
LIZED TO = 0.050 EV.
MF=3 NEUTRON CROSS SECTIONS
MT=1,4,51-75,91,102. TOTAL, ELASTIC AND INELASTIC
SCATTERING, CAPTURE CROSS SECTION
TOTAL,DIRECT ELASTIC AND DIRECT INELASTIC FOR MT=55,
59 AND OPTICAL TRANSMISSION COEFFICIENTS FROM
COUPLED CHANNELS CALCULATIONS.
THE DEFORMED OPTICAL POTENTIAL USED:
VR=(46.10-0.3*E) MEV RR=1.26 FM AR=0.615 FM
WD=(3.53+0.4*E) MEV E < 10 MEV RD=1.24 FM
WD= 7.50 MEV E=> 10 MEV AD=0.5 FM
VSO=6.2 MEV RSO=1.12 FM ASO=0.47 FM B2=0.206 B4=0.092
THREE LEVELS OF METASTABLE STATE ROTATIONAL BAND
ARE COUPLED.
CAPTURE,COMPOUND ELASTIC AND INELASTIC BY STATISTICAL
MODEL, SEE MT=18-21
ABOVE NEUTRON ENERGY 5 MEV CAPTURE IS ASSUMED TO BE
CONSTANT.
ADOPTED LEVEL SCHEME OF AM-242 FROM NUCLEAR DATA
SHEETS /7/.
No ENERGY(MEV) SPIN-PARITY K
g.s. 0.0 5 - 0
1 -0.04863 1 - 0
2 -0.00453 0 - 5
3 0.00427 3 - 0
4 0.02717 2 - 0
5 0.06537 6 - 5
6 0.09137 6 - 6
7 0.09937 5 - 0
8 0.10127 4 - 0
9 0.14137 7 - 5
10 0.14897 3 -
11 0.16837 7 - 6
12 0.17137 1 - 1
13 0.18187 2 + 1
14 0.19337 2 - 1
15 0.19547 3 - 3
16 0.21437 6 - 0
17 0.21447 7 - 0
18 0.22147 2 +
19 0.22637 3 - 1
20 0.23467 3 +
21 0.23977 4 - 3
22 0.24317 2 - 2
23 0.25637 8 - 6
24 0.25827 3 -
25 0.27037 4 - 1
OVERLAPPING LEVELS ARE ASSUMED ABOVE 0.273 MEV
LEVEL DENSITY PARAMETERS: SEE MT 18-21
MT=16,17. (N,2N) AND (N,3N) CROSS SECTION
FROM STATISTICAL MODEL CALCULATIONS /8/ WITH THE
ACCOUNT OF PRE-EQUILIBRIUM NEUTRON EMISSION:SEE MT=18-21
MT=18,19,20,21. FISSION CROSS SECTION IS CALCULATED WITHIN
STATISTICAL MODEL /9,10/, THE MEASURED DATA OF:
BROWNE ET AL./5/ AND FURSOV ET AL./11/
ARE FITTED.
THE FIRST CHANCE FISSION MT=19 IS CALCULATED WITH
THE CONTRIBUTION OF EMISSIVE FISSION TO TOTAL FISSION
CROSS SECTION ACCORDING TO /9,12/.
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
FOR MT=2, 55, 59 FROM COUPLED CHANNELS CALCULATIONS
WITH ADDED ISOTROPIC STATISTICAL CONTRIBUTION.
MT=16,17,18-21,51-54,56-58,60-75,91 - ISOTROPIC
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
ENERGY DISTRIBUTIONS FOR MT=16,17 WERE
CALCULATED BY STATISTICAL MODEL OF CASCADE NEUTRON
EMISSION TAKING INTO ACCOUNT THE HISTORY OF THE DECAY
WITH THE ALLOWANCE OF PRE-EQUILLIBRIUM EMISSION OF
THE FIRST NEUTRON /4/
ENERGY DISTRIBUTIONS FOR MT=18,19,20,21 WERE CALCULATED
BY MADLAND-NIX MODEL /2/ WITH ACCOUNT OF COMPETITION
BETWEEN MULTIPLE-CHANCE FISSION PROCESSES UP THROUGH
THIRD-CHANCE FISSION WITH THE ALLOWANCE OF PRE-EQUILIBRIUM
EMISSION OF THE FIRST NEUTRON /4,8/
REFERENCES
1. Brady M.C., Wright R.Q., England T.R., Report
ORNL/CSD/TM-226(1991), IAEA-NDS-102, 1992.
2. Madland D.G., Nix J.R., Nucl. Sci. Engng. 81, 213 (1982).
3. Howe R.E., Browne J.C., Dougan R.J., Dupzyk R.J., Landrum J.H.
Nucl. Sci. Eng.,77, 454 (1984).
4. Maslov V.M., Porodzinskij Yu.V., Sukhovitskij E.Sh., Proc.
Int. Conf. on Neutron Physics, 14-18 Sept., Kiev, USSR,
V.1, p.413, 1988.
5. Browne J.C., White R.M., Howe R.E. et al., Phys. Rev. C,
29, 2188 (1984).
6. Porodzinskij Yu.V., Sukhovitskij E.Sh., Nuclear Constants,
4, p.27, 1987 (in Russian).
7. ENSDF, 1995.
8. Ignatjuk A.V., Maslov V.M., Pashchenko A.B. Sov. J. Nucl.
Phys. 47, 224 (1988).
9. Ignatjuk A.V., Maslov V.M., Proc. Int. Symp. Nuclear Data
Evaluation Methodology, Brookhaven, USA, October 12-16, 1992,
p.440, World Scientific, 1993.
10. Maslov V.M. Sov. J. At. Energy 64, 478 (1988).
11. Fursov B.I., Samylin B.F., Smirenkin G.N., Polynov V.N.,
Nuclear Data for Science and Technology, Proc. Int. Conf.,
Gatlinburg, Tennessee, USA, May 9-13, 1994, v.1,p.269.
12. Maslov V.M., Kikuchi Y. JAERI-Research 96-030, 1996.