92-U -237 JAERI EVAL-MAR93 T.NAKAGAWA
DIST-MAR94
----JENDL-3.2 MATERIAL 9234
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
93-03 NEW EVALUATION WAS MADE FOR JENDL-3.2.
MF=1 GENERAL INFORMATION
MT=451 DESCRIPTIVE DATA AND DICTIONARY
MT=452 TOTAL NUMBER OF NEUTRONS PER FISSION
SUM OF NU-P (MT=456) AND NU-D (MT=455).
MT=455 DELAYED NEUTRON DATA
DETERMINED FROM SYSTEMATICS BY TUTTLE/1/, BENEDETTI/2/ AND
WALDO ET AL./3/ DECAY CONSTANTS WERE TAKEN FROM THE EVALU-
ATION OF BRADY AND ENGLAND/4/.
MT=456 NUMBER OF PROMPT NEUTRONS
HOWERTON'S SYSTEMATICS/5/.
MF=2 RESONANCE PARAMETERS
MT=151
1) RESOLVED RESONANCE PARAMETERS: MLBW (1.0E-5 - 200 EV)
BELOW 45 EV, HYPOTHETICAL RESONANCES WERE GENERATED FROM
FISSION WIDTH OF 0.004 EV, S0 OF 1.0E-4 AND LEVEL SPACING OF
3.5 EV, AND ADJUSTED TO REPRODUCE THERMAL CROSS SECTIONS.
ABOVE 46 EV, PARAMETERS WERE ESTIMATED FROM FISSION-AREA
DATA MEASURED BY MCNALLY ET AL./6/
2) UNRESOLVED RESONANCE PARAMETERS: 200 EV - 30 KEV
OBTAINED BY FITTING TO CAPTURE AND FISSION CROSS SECTIONS
WITH ASREP/7/.
S0 AND S2 = (0.97 - 1.02)E-4, S1 = (1.95 - 2.04)E-4,
GAMMA-F = (0.006 - 0.070) EV, GAMMA-G = 0.035 EV
R = 9.668 FM
CALCULATED THERMAL CROSS SECTIONS AND RES. INTEGRAL (BARNS)
0.0253 EV RESONANCE INTEGRAL
TOTAL 478.5 -
ELASTIC 24.39 -
FISSION 1.70 48.7
CAPTURE 452.4 1080
MF=3 NEUTRON CROSS SECTIONS
BELOW 200 EV, CROSS SECTIONS WERE REPRESENTED WITH RESOLVED
RESONANCE PARAMETERS. ABOVE 200 EV, THEY WERE EVALUATED AS
FOLLOWS, AND THE UNRESOLVED RESONANCE PARAMETERS WERE GIVEN
SO AS TO REPRODUCE THE CROSS SECTIONS IN THE ENERGY RANGE
FROM 200 EV TO 30 KEV.
MT= 1 TOTAL CROSS SECTION
CALCULATED FROM THE OPTICAL MODEL WITH CASTHY/8/.
PARAMETERS ARE LISTED IN TABLE 1.
MT= 2 ELASTIC SCATTERING CROSS SECTION
TOTAL - SUM OF PARTIAL CROSS SECTIONS
MT= 16, 17 (N,2N) AND (N,3N) CROSS SECTIONS
CALCULATED FROM A FORMULA GIVEN BY SAGEV AND CANER/9/.
THE REACTION CROSS SECTIONS CALCULATED WITH CASTHY WAS
ADOPTED AS THE NON-ELASTIC SCATTERING CROSS SECTION.
MT= 18 FISSION CROSS SECTION
CROSS SECTION OF 2.5 B AT 200 EV WAS ASSUMED FROM THE DATA
OF MCNALLY ET AL./6/ CROSS SECTION AT 100 KEV WAS ASSUMED
TO BE 0.6 B. ABOVE 5 MEV, A SIMPLE FORMULA BY BYCHKOV ET
AL./9/ WAS USED. EXPERIMENTAL DATA OF CRAMER AND BRITT/10/
AND SYSTEMATICS/11/ WERE ALSO CONSIDERED.
MT= 4, 51-79, 91 INELASTIC SCATTERING CROSS SECTION
CALCULATED WITH CASTHY (OPTICAL AND STATISTICAL MODEL).
PARAMETERS USED ARE LISTED IN TABLES 1, 2 AND 3. THE LEVEL
SCHEME WAS TAKEN FROM EVALUATION BY ELLIS-AKOVALI/12,13/.
MT= 102 CAPTURE CROSS SECTION
CALCULATED WITH CASTHY. AVERAGE CAPTURE WIDTH AND LEVEL
SPACING WAS ASSUMED TO BE 0.035 EV AND 3.5 EV, RESPECTIVELY.
DIRECT AND SEMI-DIRECT CAPTURE WAS CALCULATED FROM A SIMPLE
FORMULA OF BENZI AND REFFO/14/.
MT= 251 MU-L
CALCULATED WITH CASTHY
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
MT= 2, 51-79, 91
CALCULATED WITH CASTHY
MT=16, 17, 18
ASSUMED TO BE ISOTROPIC IN THE LABORATORY SYSTEM.
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=16, 17, 91
EVAPORATION SPECTRA OBTAINED FROM THE LEVEL DENSITY
PARAMETERS WERE GIVEN.
MT=18
EVAPORATION SPECTRA. TEMPERATURE WAS DETERMINED FROM
SYSTEMATICS BY SMITH ET AL./15/
TABLE 1 OPTICAL POTENTIAL PARAMETERS
DETERMINED BY MURATA/16/ EXCEPT A CONSTANT TERM OF V
THAT WAS SELECTED SO AS TO REPRODUCE S0 OF 1.0E-4.
-------------------------------------------------------------
V = 40.5 - 0.05*E (MEV)
WS = 6.5 + 0.15*E (MEV): DERRIVATIVE WOOD-SAXON TYPE
VSO = 7.0 (MEV)
R0 = RSO = 1.32, RS = 1.38 (FM)
A = B = ASO = 0.47 (FM)
-------------------------------------------------------------
TABLE 2 LEVEL SCHEME OF U-237 /12,13/
-------------------------------------------------------------
NO. ENERGY(MEV) SPIN-PARITY
-------------------------------------------------------------
G.S 0.0 1/2 +
1 0.01139 3/2 +
2 0.05630 5/2 +
3 0.08286 7/2 +
4 0.15996 5/2 +
5 0.20419 7/2 +
6 0.2740 7/2 -
7 0.3160 9/2 -
8 0.42615 7/2 +
9 0.4820 9/2 +
10 0.54062 1/2 -
11 0.55498 3/2 -
12 0.57801 5/2 -
13 0.66427 3/2 +
14 0.66645 5/2 +
15 0.67759 3/2 +
16 0.69765 5/2 +
17 0.72045 3/2 -
18 0.73434 1/2 -
19 0.75816 3/2 -
20 0.83245 5/2 +
21 0.84694 1/2 +
22 0.8650 1/2 -
23 0.87215 3/2 +
24 0.89343 5/2 +
25 0.9034 3/2 -
26 0.9057 1/2 +
27 0.9094 1/2 -
28 0.9110 5/2 -
29 0.9206 3/2 +
-------------------------------------------------------------
LEVELS ABOVE 0.94785 MEV WERE ASSUMED TO BE OVERLAPPING.
TABLE 3 LEVEL DENSITY PARAMETERS FOR GILBERT AND CAMERON
FORMULA, BASED ON THE EXCITED LEVELS GIVEN IN ENSDF
AND RESONANCE LEVEL SPACINGS /17/.
-------------------------------------------------------------
PAIRING SPIN-CUTOFF F.
A(1/MEV) T(MEV) ENERGY(MEV) (MEV**0.5) EX(MEV)
-------------------------------------------------------------
U-235 31.4 0.39 0.69 31.55 4.1984
U-236 30.42 0.39 1.18 30.752 4.5349
U-237 31.6 0.37 0.69 31.431 3.807
U-238 30.1 0.38 1.12 30.762 4.227
-------------------------------------------------------------
REFERENCES
1) R.J.TUTTLE: INDC(NDS)-107/G+SPECIAL, P.29 (1979).
2) G.BENEDETTI, ET AL.: NUCL. SCI. ENG., 80, 379 (1982).
3) R.WALDO ET AL.: PHYS. REV., C23, 1113 (1981).
4) M.C.BRADY AND T.R.ENGLAND: NUCL. SCI. ENG., 103, 129 (1989).
5) R.J.HOWERTON: NUCL. SCI. ENG., 62, 438 (1977).
6) J.H.MCNALLY ET AL: PHYS. REV., C9, 717 (1974).
7) Y.KIKUCHI: UNPUBLISHED.
8) S.IGARASI AND T.FUKAHORI: JAERI 1321 (1991).
9) V.M.BYCHKOV ET AL.: INDC(CCP)-184/L (1982).
10) J.D.CRAMER AND H.C.BRITT: NUCL. SCI. ENG., 41, 177 (1970).
11) J.W.BEHRENS AND R.J.HOWERTON: NUCL. SCI. ENG., 65, 464 (1978).
12) Y.A.ELLIS-AKOVALI: NUCLEAR DATA SHEETS, 49, 181 (1986).
13) ENSDF: EVALUATED NUCLEAR STRUCTURE DATA FILE, BNL/NNDC, AS OF
JAN. 1993.
14) V.BENZI AND G.REFFO: CCDN-NW/10 (1969).
15) A.B.SMITH ET AL.: ANL/NDM-50 (1979).
16) H.MATSUNOBU ET AL.: PROC. IN. CONF. ON NUCLEAR CROSS SECTIONS
FOR TECHNOL., KNOXVILLE, 1979, P.715 (1980).
17) S.F.MUGHABGHAB: NEUTRON CROSS SECTIONS, VOL.1, PART A,
ACADEMIC PRESS (1984).