93-NP-238 JAERI EVAL-MAR93 T.NAKAGAWA
DIST-MAR94
----JENDL-3.2 MATERIAL 9349
-----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 BY BRADY AND ENGLAND/4/.
MT=456 NUMBER OF PROMPT NEUTRONS
BASED ON THE DATA BY SOLONKIN ET AL./5/ AND HOWERTON'S
SYSTEMATICS/6/. A CONSTANT TERM IS AN AVERAGE OF THESE
TWO.
MF=2 RESONANCE PARAMETERS
MT=151 NO RESONANCE PARAMETERS ARE GIVEN.
THERMAL CROSS SECTIONS AND CALCULATED RES. INTEGRAL (BARNS)
0.0253 EV RESONANCE INTEGRAL
TOTAL 2532.5 -
ELASTIC 12.41 -
FISSION 2070. 940
CAPTURE 450. 201
MF=3 NEUTRON CROSS SECTIONS
MT= 1 TOTAL CROSS SECTION
CALCULATED WITH OPTICAL MODEL CODE CASTHY/7/. 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/8/.
THE REACTION CROSS SECTIONS CALCULATED WITH CASTHY WAS
ADOPTED AS THE NON-ELASTIC SCATTERING CROSS SECTION.
MT= 18 FISSION CROSS SECTION
CROSS SECTION OF 2070 BARNS MEASURED BY SPENCER AND BAUMANN
AT 0.0253 EV/9/ WAS ADOPTED AND 1/V FORM ASSUMED BELOW 20
KEV. ABOVE 6.6 MEV, A SIMPLE FORMULA BY BYCHKOV ET AL./8/
WAS USED. BELOW THIS, EXPERIMENTAL DATA OF BRITT AND
WILHELMY/10/ AND SYSTEMATICS/11/ WERE CONSIDERED. THE
CROSS-SECTION CURVE WAS SMOOTHLY CONNECTED AT 20 KEV TO THE
ABOVE-MENTIONED DATA.
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 SHURSHIKOV/12,13/.
MT= 102 CAPTURE CROSS SECTION
CALCULATED WITH CASTHY. AVERAGE CAPTURE WIDTH AND LEVEL
SPACING WAS ASSUMED TO BE 0.035EV AND 0.294EV, 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 NP-238 /12,13/
-------------------------------------------------------------
NO. ENERGY(MEV) SPIN-PARITY
-------------------------------------------------------------
G.S 0.0 2 +
1 0.02643 3 +
2 0.06222 4 +
3 0.08665 3 +
4 0.10626 5 +
5 0.12176 4 +
6 0.13601 3 -
7 0.16577 5 +
8 0.17915 4 -
9 0.18286 2 -
10 0.21548 3 -
11 0.22120 6 +
12 0.23280 5 -
13 0.25870 4 -
14 0.27558 5 +
15 0.2860 1 -
16 0.2983 6 -
17 0.30091 6 -
18 0.3286 6 +
19 0.3325 1 +
20 0.34238 5 -
21 0.3501 3 -
22 0.36841 2 -
23 0.3741 2 +
24 0.4085 6 -
25 0.4313 4 +
26 0.4404 4 -
27 0.4563 5 +
28 0.4626 6 +
29 0.5242 6 +
-------------------------------------------------------------
LEVELS ABOVE 0.528 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)
-------------------------------------------------------------
NP-236 28.0 0.35 0.0 29.50 2.2579
NP-237 29.6 0.39 0.49 30.42 3.7161
NP-238 30.0 0.344 0.0 30.71 2.4075
NP-239 30.38 0.376 0.43 31.00 3.4944
-------------------------------------------------------------
* TAKEN FROM GILBERT AND CAMERON/18/
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) A.A.SOLONKIN ET AL.: ATOM. ENERGY, 64, 497 (1988).
6) R.J.HOWERTON: NUCL. SCI. ENG., 62, 438 (1977).
7) S.IGARASI AND T.FUKAHORI: JAERI 1321 (1991).
8) V.M.BYCHKOV ET AL.: INDC(CCP)-184/L (1982).
9) J.D.SPENCER AND N.P.BAUMANN: TRANS. AMER. NUCL. SOC., 12, 284
(1969). DATA WERE TAKEN FROM EXFOR 12475.
10) H.C.BRITT AND J.B.WILHELMY: NUCL. SCI. ENG., 72, 222 (1979).
11) J.W.BEHRENS AND R.J.HOWERTON: NUCL. SCI. ENG., 65, 464 (1978).
12) E.N.SHURSHIKOV: NUCLEAR DATA SHEETS, 53, 601 (1988).
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).
18) A.GILBERT AND A.G.W.CAMERON: CAN. J. PHYS., 43, 1446 (1965).