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98-Cf-250 JAERI EVAL-MAR86 T.NAKAGAWA
JAERI-M 86-086 DIST-JAN09 20090105
----JEFF-311 MATERIAL 9855
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
*************************** JEFF-3.1.1 *************************
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** Original data taken from: JEFF-3.1 **
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***************************** JEFF-3.1 *************************
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** Original data taken from: JENDL-3.3 **
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JENDL-3.2 data were automatically transformed to JENDL-3.3.
Interpolation of spectra: 22 (unit base interpolation)
(3,251) deleted, T-matrix of (4,2) deleted, and others.
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HISTORY
86-03 NEW EVALUATION WAS MADE BY T.NAKAGAWA (JAERI).
DETAILS ARE DESCRIBED IN REF. /1/.
MF=1 GENERAL INFORMATION
MT=451 COMMENTS AND DICTIONARY
MT=452 NUMBER OF NEUTRONS PER FISSION
SUM OF MT=455 AND MT=456
MT=455 DELAYED NEUTRON DATA
BASED ON SEMI-EMPIRICAL FORMULA BY TUTTLE /2/.
MT=456 NUMBER OF PROMPT NEUTRONS PER FISSION
BASED ON SEMI-EMPIRICAL FORMULA BY HOWERTON /3/.
MF=2,MT=151 RESONANCE PARAMETERS
RESOLVED RESONANCES FOR SLBW FORMULA : 1.0E-5 EV TO 150 EV
HYPOTHETICAL RESONANCE LEVELS WERE GENERATED, AND THEIR
PARAMETERS WERE DETERMINED FROM THE ASSUMED AVERAGE PARAMETERS
D-0 = 16 EV, RADIATIVE CAPTURE WIDTH = 0.0369 EV,
S-0 = 1.0E-4, FISSION WITH = 0.0001 EV, R = 9.252 FM.
PARAMETERS OF THE NEGATIVE AND FIRST POSITIVE LEVELS WERE
ADJUSTED SO AS TO REPRODUCE THE THERMAL CROSS SECTIONS AND
RESONANCE INTEGRALS.
UNRESOLVED RESONANCES : 150 EV TO 30 KEV
S-0 = 1.0E-4, S-1 = 3.3E-4, D-0=16 EV, R = 9.11 FM,
RADIATIVE WIDTH = 0.0369 EV, FISSION WIDTH = 0.0001 EV.
THE SCATTERING RADIUS WAS ADJUSTED SLIGHTLY.
CALCULATED 2200 M/S CROSS SECTIONS AND RESONANCE INTEGRALS
2200 M/S VALUE RES. INT.
TOTAL 1950.7 B -
ELASTIC 167.4 B -
FISSION 4.09 B 27.8 B
CAPTURE 1779.2 B 8420 B
MF=3 NEUTRON CROSS SECTIONS
MT=1 TOTAL
MT=2 ELASTIC SCATTERING
MT=4, 51 TO 79 AND 91 INELASTIC SCATTERING
MT=102 RADIATIVE CAPTURE
MT=251 MU-BAR
CALCULATED WITH THE PROGRAM CASTHY /4/ BASED ON THE OPTICAL
AND STATISTICAL MODELS. OPTICAL POTENTIAL PARAMETERS WERE
OBTAINED /5/ BY FITTING THE TOTAL CROSS SECTION OF PHILLIPS
AND HOWE /6/ FOR AM-241:
V = 43.4 - 0.107*EN (MEV)
WS= 6.95 - 0.339*EN + 0.0531*EN**2 (MEV)
WV= 0 , VSO = 7.0 (MEV)
R = RSO = 1.282 , RS = 1.29 (FM)
A = ASO = 0.60 , B = 0.5 (FM)
IN THE STATISTICAL CALCULATION, LEVEL FLUCTUATION AND
COMPETING PROCESS (FISSION, (N,2N) AND (N,3N)) WERE TAKEN INTO
ACCOUNT. THE LEVEL SCHEME WAS TAKEN FROM REF. /7/.
NO. ENERGY(KEV) J-PARITY NO. ENERGY(KEV) J-PARITY
------------------------- ------------------------
GROUND 0.0 0 + 15 1209.98 2 -
1 42.722 2 + 16 1211. 3 -
2 141.886 4 + 17 1244.51 2 +
3 296.25 6 + 18 1255.47 4 -
4 871.64 2 - 19 1266.65 0 +
5 905.90 3 - 20 1296.64 2 +
6 952.07 4 - 21 1311.07 5 -
7 1008.6 5 - 22 1335. 3 -
8 1031.85 2 + 23 1377.83 6 -
9 1070. 6 - 24 1385.49 (1 +)
10 1071.38 3 + 25 1396.16 5 -
11 1123. 4 + 26 1411.34 (1 +)
12 1154.23 0 + 27 1426.86 3 -
13 1175.52 1 - 28 1457.83 6 -
14 1189.40 2 + 29 1478.45 5 -
------------------------- ------------------------
LEVELS ABOVE 1.50 MEV WERE ASSUMED TO BE OVERLAPPING.
THE LEVEL DENSITY PARAMETERS WERE DERIVED FROM RESONANCE LEVEL
SPACINGS AND LOW LAYING EXCITED LEVELS ON THE BASIS OF
GILBERT-CAMERON'S FOUMULA /8/. THE AVERAGE RADIATIVE CAPTURE
WIDTH OF 0.0369 EV AND S-WAVE LEVEL SPACING OF 16 EV WERE
ASSUMED.
MT=16 AND 17 (N,2N) AND (N,3N)
CALCULATED WITH EVAPORATION MODEL.
MT=18 FISSION
EVALUATED ON THE BASIS OF THE SYSTEMATICS.
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=2,51-79 CALCULATED WITH OPTICAL MODEL.
MT=16,17,18,91 ISOTROPIC DISTRIBUTIONS IN THE LABORATORY
SYSTEM WERE ASSUMED.
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=16,17,91 EVAPORATION SPECTRUM.
MT=18 MAXWELLIAN FISSION SPECTRUM.
TEMPERATURE ESTIMATED FROM SYSTEMATICS OF
SMITH ET AL./9/.
REFERENCES
1) NAKAGAWA, T.: JAERI-M 86-086 (1986).
2) TUTTLE, R.J.: INDC(NDS)-107/G+SPECIAL, P.29 (1979).
3) HOWERTON, R.J.: NUCL. SCI. ENG., 62, 438 (1977).
4) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975).
5) IGARASI, S. AND NAKASAWA, T.: JAERI-M 8342 (1979).
6) PHILLIPS, T.W. AND HOWE, F.R.: NUCL. SCI. ENG., 69, 375(1979).
7) SCHMORAK, M.R.: NUCL. DATA SHEETS, 32, 87 (1981).
8) GILBERT A. AND CAMERON A.G.W.: CAN. J. PHYS., 43, 1446 (1965).
9) SMITH A.B. ET AL.: ANL/NDM-50 (1979).
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