12-Mg- 24
12-MG- 24 DEC,NEDAC EVAL-MAR87 M.HATCHYA(DEC), T.ASAMI(NEDAC)
DIST-SEP89 REV2-APR93
----JENDL-3.2 MATERIAL 1225
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
87-03 NEW EVALUATION WAS MADE FOR JENDL-3.
87-03 COMPILED BY T.ASAMI.
93-04 JENDL-3.2
COMPILED BY T.NAKAGAWA (NDC/JAERI)
***** MODIFIED PARTS FOR JENDL-3.2 ********************
(4,91) CHANGED TO THE LABORATORY SYSTEM
***********************************************************
MF=1 GENERAL INFORMATION
MT=451 DESCRIPTIVE DATA AND DICTIONARY
MF=2 RESONANCE PARAMETERS
MT=151 RESOLVED RESONANCE PARAMETERS
RESOLVED PARAMETERS FOR MLBW FORMULA WERE GIVEN IN THE ENERGY
REGION FROM 1.0E-5 EV TO 520 KEV. PARAMETERS WERE TAKEN FROM
THE RECOMMENDED DATA OF BNL/1/ AND THE DATA FOR A NEGATIVE
RESONANCE WERE ADDED SO AS TO REPRODUCE THE RECOMMENDED THERMAL
CROSS SECTIONS FOR CAPTURE AND SCATTERING/1/. THE DATA FOR
SOME LEVELS WERE MODIFIED SO THAT THE CALCULATED TOTAL CROSS
SECTIONS OF THE ELEMENT MG WERE FITTED TO THE EXPERIMENTAL DATA
OF HIBDON/2/ AND SINGH/3/. THE SCATTERING RADIUS WAS ASSUMED
TO BE 5.4 FERMI. CALCULATED 2200 M/SEC CROSS SECTIONS AND
RESONANCE INTEGRALS ARE AS FOLLOWS:
2200 M/S CROSS SECTION(B) RES. INTEGRAL(B)
ELASTIC 3.75
CAPTURE 0.050 0.0312
TOTAL 3.80
MF=3 NEUTRON CROSS SECTIONS
BELOW 520 KEV, NO BACKGROUND CROSS SECTION IS GIVEN AND ALL THE
CROSS-SECTION DATA ARE REPRODUCED FROM THE EVALUATED RESOLVED
RESONANCE PARAMETERS WITH THE MLBW FORMULA.
ABOVE 520 KEV, THE TOTAL AND PARTIAL CROSS SECTIONS ARE GIVEN IN
THE POINTWISE FORM.
MT=1 TOTAL
OPTICAL AND STATISTICAL MODEL CALCULATION WAS MADE WITH
CASTHY CODE/4/. THE OPTICAL POTENTIAL PARAMETERS USED ARE:
V = 49.68, VSO = 7.12 (MEV)
WS = 7.76 - 0.5*EN, WV = 0 (MEV)
R = 1.17, RS = 1.09, RSO = 1.17 (FM)
A = 0.6, ASO = 0.6, B = 0.69 (FM)
MT=2 ELASTIC SCATTERING
OBTAINED BY SUBTRACTING THE SUM OF THE PARTIAL CROSS SECTIONS
FROM THE TOTAL CROSS SECTION.
MT=4, 51-61, 91 INELASTIC SCATTERING
CALCULATED WITH CASTHY /4/, TAKING ACCOUNT OF THE CONTRIBUTION
FROM THE COMPETING PROCESSES. THE DIRECT COMPONENTS FOR MT=51
AND 52 WERE, CALCULATED WITH THE DWUCK/5/. THE CALCULATED DATA
FOR THE FIRST LEVEL WERE NORMALIZED AT 12 MEV TO THE EXPERIMEN-
TAL DATA/6/. THE LEVEL DATA USED IN THESE TWO CALCULATIONS WERE
TAKEN FROM REF./7/ AS FOLLOWS:
MT LEVEL ENERGY(MEV) SPIN-PARITY
0.0 0+
51 1.3686 2+
52 4.1200 4+
53 4.2384 2+
54 5.2361 3+
55 6.0103 4+
56 6.4322 0+
57 7.3479 2+
58 7.5530 1-
59 7.6162 3-
60 7.7472 1+
61 7.8120 3+
LEVELS ABOVE 10.0 MEV WERE ASSUMED TO BE OVERLAPPING.
MT=16, 22, 28, 103, 107 (N,2N), (N,NA), (N,NP), (N,P), (N,A)
CALCULATED WITH THE GNASH CODE/8/ USING THE ABOVE OPTICAL MODEL
PARAMETERS. THE (N,2N) CROSS SECTIONS WERE MODIFIED SO AS TO
FIT TO THE EXPERIMENTAL DATA.
MT=102 CAPTURE
CALCULATED WITH THE CASTHY CODE/4/ AND NORMALIZED TO 1.8 MB
AT 30 KEV.
MT=251 MU-BAR
CALCULATED WITH THE OPTICAL MODEL.
MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=2
CALCULATED WITH THE CASTHY CODE/4/.
MT=51-61
CALCULATED WITH THE CASTHY CODE/4/, AND CONTRIBUTIONS FROM THE
DIRECT PROCESS CALCULATED WITH THE DWUCK CODE/5/ WERE ADDED TO
MT=51 AND 52.
MT=91
CALCULATED WITH THE CASTHY CODE/4/ AND TRANSFORMED INTO THE
LABORATORY SYSTEM.
MT=16, 22, 28
ASSUMED TO BE ISOTOROPIC IN THE LABORATORY SYSTEM.
MF=5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
MT=16, 22, 28, 91
CALCULATED WITH THE GNASH CODE/8/.
REFERENCES
1) MUGHABGHAB S.F. AND GARBER D.I. :"NEUTRON CROSS SECTIONS", VOL.
1, PART B (1984).
2) HIBDON C.T. : TAKEN FROM EXFOR (1969).
3) SINGH U.N. ET AL. : PHYS. REV. C10, 2150 (1974).
4) IGARASI S. : J. NUCL. SCI. TECH. 12, 67 (1975).
5) KUNZ P.D. : UNPUBLISHED.
6) FOERTSCH ET AL. : NUCL. INSTR. METH. 169, 533 (1980).
7) ENSDF(EVALUATED NUCLEAR STRUCTURE DATA FILE)
8) YOUNG P.G. AND ARTHUR E.D. : LA-6947 (1977).