98-Cf-251
98-CF-251 JAERI EVAL-MAR86 T.NAKAGAWA
JAERI-M 86-086 DIST-SEP89
----JENDL-3.2 MATERIAL 9858
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
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 = 6.3 EV, RADIATIVE CAPTURE WIDTH = 0.0435 EV,
S-0 = 1.0E-4, FISSION WITH = 0.0746 EV, R = 9.253 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
PARAMETERS WERE ADJUSTED SO AS TO REPRODUCE THE ASSUMED
FISSION AND RADIATIVE CAPTURE CROSS SECTIONS.
S-0 = 0.843E-4, S-1 = 4.56E-4, R = 8.842 FM,
D-0 = 6.3 EV, RADIATIVE WIDTH = 0.0435 EV,
FISSION WIDTH = 0.281 EV (FOR L=0), = 0.551 EV (FOR L=1)
CALCULATED 2200 M/S CROSS SECTIONS AND RESONANCE INTEGRALS
2200-M/S VALUE RES. INT.
TOTAL 7889.4 B -
ELASTIC 76.04 B -
FISSION 4935.4 B 2780. B
CAPTURE 2877.9 B 1600. B
MF=3 NEUTRON CROSS SECTIONS
MT=1 TOTAL
MT=2 ELASTIC SCATTERING
MT=4, 51 TO 73 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), (N,3N) AND (N,4N)) 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 1/2 + 12 295.7 13/2 +
1 24.825 3/2 + 13 319.29 9/2 +
2 47.828 5/2 + 14 325.35 13/2 +
3 105.73 7/2 + 15 370.39 11/2 -
4 106.304 7/2 + 16 392.0 11/2 +
5 146.46 9/2 + 17 424.10 15/2 +
6 166.31 9/2 + 18 434.3 9/2 -
7 177.69 3/2 + 19 442. 13/2 -
8 211.72 5/2 + 20 514. 11/2 -
9 237.76 11/2 + 21 544.05 5/2 +
10 239.34 11/2 + 22 590.18 7/2 +
11 258.44 7/2 + 23 649.2 9/2 +
------------------------- ------------------------
LEVELS ABOVE 700 KEV 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 0.0435 EV AND S-WAVE LEVEL SPACING OF 6.3 EV WERE
ASSUMED.
MT=16,17 AND 37 (N,2N), (N,3N) AND (N,4N)
CALCULATED WITH EVAPORATION MODEL.
MT=18 FISSION
EVALUATED ON THE BASIS OF THE SYSTEMATICS.
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=2,51-73 CALCULATED WITH OPTICAL MODEL.
MT=16,17,18,37,91 ISOTROPIC DISTRIBUTIONS IN THE LABORATORY
SYSTEM WERE ASSUMED.
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=16,17,37,91 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).