50-Sn-126
50-SN-126 JNDC EVAL-MAR90 JNDC FP NUCLEAR DATA W.G.
DIST-NOV90
----JENDL-3.2 MATERIAL 5067
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
90-03 NEW EVALUATION FOR JENDL-3 WAS COMPLETED BY JNDC FPND
W.G./1/
MF = 1 GENERAL INFORMATION
MT=451 COMMENTS AND DICTIONARY
MF = 2 RESONANCE PARAMETERS
MT=151 RESOLVED AND UNRESOLVED RESONANCE PARAMETERS
NO RESOLVED RESONANCE PARAMETERS
UNRESOLVED RESONANCE REGION : 2 KEV - 100 KEV
THE NEUTRON STRENGTH FUNCTIONS, S0, S1 AND S2 WERE CALCULATED
WITH OPTICAL MODEL CODE CASTHY/2/. THE OBSERVED LEVEL SPACING
WAS DETERMINED TO REPRODUCE THE CAPTURE CROSS SECTION
CALCULATED WITH CASTHY. THE EFFECTIVE SCATTERING RADIUS WAS
OBTAINED FROM FITTING TO THE CALCULATED TOTAL CROSS SECTION AT
100 KEV. THE RADIATON WIDTH GG WAS BASED ON THE SYSTEMATICS
OF MEASURED VALUES FOR NEIGHBORING NUCLIDES.
TYPICAL VALUES OF THE PARAMETERS AT 70 KEV:
S0 = 0.750E-4, S1 = 2.500E-4, S2 = 0.670E-4, SG = 0.107E-4,
GG = 0.150 EV, R = 5.582 FM.
CALCULATED 2200-M/S CROSS SECTIONS AND RES. INTEGRALS (BARNS)
2200 M/S RES. INTEG.
TOTAL 4.090 -
ELASTIC 4.000 -
CAPTURE 0.09000 0.150
MF = 3 NEUTRON CROSS SECTIONS
BELOW 2 KEV, THE CAPTURE AND ELASTIC SCATTERING CROSS SECTIONS
WERE ASSUMED TO BE IN 1/V FORM AND CONSTANT, RESPECTIVELY. THE
CAPTURE CROSS SECTION AT 0.0253 EV WAS DETERMINED BY THE
SYSTEMATICS FROM NEIGHBORING NUCLIDES, AND SCATTERING CROSS
SECTION FROM R = 5.4 FM. UNRESOLVED RESONANCE PARAMETERS WERE
GIVEN IN THE ENERGY RANGE FROM 2 KEV TO 100 KEV.
ABOVE 100 KEV, THE SPHERICAL OPTICAL AND STATISTICAL MODEL
CALCULATION WAS PERFORMED WITH CASTHY, BY TAKING ACCOUNT OF
COMPETING REACTIONS, OF WHICH CROSS SECTIONS WERE CALCULATED
WITH PEGASUS/3/ STANDING ON A PREEQUILIBRIUM AND MULTI-STEP
EVAPORATION MODEL. THE OMP'S FOR NEUTRON GIVEN IN TABLE 1 WERE
DETERMINED SO AS TO REPRODUCE A SYSTEMATIC TREND OF THE TOTAL
CROSS SECTION BY CHANGING RSO OF IIJIMA-KAWAI POTENTIAL/4/. THE
OMP'S FOR CHARGED PARTICLES ARE AS FOLLOWS:
PROTON = PEREY/5/
ALPHA = HUIZENGA AND IGO/6/
DEUTERON = LOHR AND HAEBERLI/7/
HELIUM-3 AND TRITON = BECCHETTI AND GREENLEES/8/
PARAMETERS FOR THE COMPOSITE LEVEL DENSITY FORMULA OF GILBERT
AND CAMERON/9/ WERE EVALUATED BY IIJIMA ET AL./10/ MORE
EXTENSIVE DETERMINATION AND MODIFICATION WERE MADE IN THE
PRESENT WORK. TABLE 2 SHOWS THE LEVEL DENSITY PARAMETERS USED
IN THE PRESENT CALCULATION. ENERGY DEPENDENCE OF SPIN CUT-OFF
PARAMETER IN THE ENERGY RANGE BELOW E-JOINT IS DUE TO GRUPPELAAR
/11/.
MT = 1 TOTAL
SPHERICAL OPTICAL MODEL CALCULATION WAS ADOPTED.
MT = 2 ELASTIC SCATTERING
CALCULATED AS (TOTAL - SUM OF PARTIAL CROSS SECTIONS).
MT = 4, 51 - 91 INELASTIC SCATTERING
SPHERICAL OPTICAL AND STATISTICAL MODEL CALCULATION WAS
ADOPTED. THE LEVEL SCHEME WAS BASED ON EVALUATED NUCLEAR
STRUCTURE DATA FILE (1987 VERSION)/12/ AND NUCLEAR DATA
SHEETS/13/.
NO. ENERGY(MEV) SPIN-PARITY
GR. 0.0 0 +
1 1.1411 2 +
2 2.0497 4 +
3 2.1108 2 +
4 2.1301 4 +
5 2.1615 5 -
6 2.1942 4 +
7 2.2189 7 -
LEVELS ABOVE 2.25 MEV WERE ASSUMED TO BE OVERLAPPING.
MT = 102 CAPTURE
SPHERICAL OPTICAL AND STATISTICAL MODEL CALCULATION WITH
CASTHY WAS ADOPTED. DIRECT AND SEMI-DIRECT CAPTURE CROSS
SECTIONS WERE ESTIMATED ACCORDING TO THE PROCEDURE OF BENZI
AND REFFO/14/ AND NORMALIZED TO 1 MILLI-BARN AT 14 MEV.
THE GAMMA-RAY STRENGTH FUNCTION (9.55E-06) WAS ADJUSTED TO
REPRODUCE THE CAPTURE CROSS SECTION OF 5 MILLI-BARNS AT 300
KEV, WHICH WAS ESTIMATED FROM THE DATA OF NEIGHBORING
NUCLIDES.
MT = 16 (N,2N) CROSS SECTION
MT = 17 (N,3N) CROSS SECTION
MT = 22 (N,N'A) CROSS SECTION
MT = 28 (N,N'P) CROSS SECTION
MT =103 (N,P) CROSS SECTION
MT =104 (N,D) CROSS SECTION
MT =105 (N,T) CROSS SECTION
MT =107 (N,ALPHA) CROSS SECTION
THESE REACTION CROSS SECTIONS WERE CALCULATED WITH THE
PREEQUILIBRIUM AND MULTI-STEP EVAPORATION MODEL CODE PEGASUS.
THE KALBACH'S CONSTANT K (= 232.5) WAS ESTIMATED BY THE
FORMULA DERIVED FROM KIKUCHI-KAWAI'S FORMALISM/15/ AND LEVEL
DENSITY PARAMETERS.
MT = 251 MU-BAR
CALCULATED WITH CASTHY.
MF = 4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS
LEGENDRE POLYNOMIAL COEFFICIENTS FOR ANGULAR DISTRIBUTIONS ARE
GIVEN IN THE CENTER-OF-MASS SYSTEM FOR MT=2 AND DISCRETE INELAS-
TIC LEVELS, AND IN THE LABORATORY SYSTEM FOR MT=91. THEY WERE
CALCULATED WITH CASTHY. FOR OTHER REACTIONS, ISOTROPIC DISTRI-
BUTIONS IN THE LABORATORY SYSTEM WERE ASSUMED.
MF = 5 ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS
ENERGY DISTRIBUTIONS OF SECONDARY NEUTRONS WERE CALCULATED WITH
PEGASUS FOR INELASTIC SCATTERING TO OVERLAPPING LEVELS AND FOR
OTHER NEUTRON EMITTING REACTIONS.
TABLE 1 NEUTRON OPTICAL POTENTIAL PARAMETERS
DEPTH (MEV) RADIUS(FM) DIFFUSENESS(FM)
---------------------- ------------ ---------------
V = 47.64-0.473E R0 = 6.256 A0 = 0.62
WS = 9.744 RS = 6.469 AS = 0.35
VSO= 7.0 RSO= 6.241 ASO= 0.62
THE FORM OF SURFACE ABSORPTION PART IS DER. WOODS-SAXON TYPE.
TABLE 2 LEVEL DENSITY PARAMETERS
NUCLIDE SYST A(1/MEV) T(MEV) C(1/MEV) EX(MEV) PAIRING
---------------------------------------------------------------
48-CD-122 * 1.667E+01 5.968E-01 2.388E-01 6.394E+00 2.450E+00
48-CD-123 * 1.641E+01 5.943E-01 1.268E+00 5.165E+00 1.360E+00
48-CD-124 * 1.614E+01 5.919E-01 1.426E-01 6.225E+00 2.560E+00
48-CD-125 * 1.587E+01 5.895E-01 9.238E-01 4.884E+00 1.360E+00
49-IN-123 1.470E+01 6.100E-01 1.134E+00 4.483E+00 1.090E+00
49-IN-124 1.655E+01 5.240E-01 6.345E+00 2.747E+00 0.0
49-IN-125 * 1.627E+01 5.895E-01 1.449E+00 4.874E+00 1.200E+00
49-IN-126 1.600E+01 5.160E-01 4.768E+00 2.470E+00 0.0
50-SN-124 1.601E+01 6.160E-01 3.224E-01 6.294E+00 2.280E+00
50-SN-125 1.591E+01 6.210E-01 1.927E+00 5.249E+00 1.190E+00
50-SN-126 1.646E+01 6.270E-01 4.012E-01 6.778E+00 2.390E+00
50-SN-127 1.577E+01 6.140E-01 1.633E+00 5.075E+00 1.190E+00
---------------------------------------------------------------
SYST: * = LDP'S WERE DETERMINED FROM SYSTEMATICS.
SPIN CUTOFF PARAMETERS WERE CALCULATED AS 0.146*SQRT(A)*A**(2/3).
IN THE CASTHY CALCULATION, SPIN CUTOFF FACTORS AT 0 MEV WERE
ASSUMED TO BE 1.141 FOR SN-126 AND 5.0 FOR SN-127.
REFERENCES
1) KAWAI, M. ET AL.: PROC. INT. CONF. ON NUCLEAR DATA FOR SCIENCE
AND TECHNOLOGY, MITO, P. 569 (1988).
2) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975).
3) IIJIMA, S. ET AL.: JAERI-M 87-025, P. 337 (1987).
4) IIJIMA, S. AND KAWAI, M.: J. NUCL. SCI. TECHNOL., 20, 77
(1983).
5) PEREY, F.G: PHYS. REV. 131, 745 (1963).
6) HUIZENGA, J.R. AND IGO, G.: NUCL. PHYS. 29, 462 (1962).
7) LOHR, J.M. AND HAEBERLI, W.: NUCL. PHYS. A232, 381 (1974).
8) BECCHETTI, F.D., JR. AND GREENLEES, G.W.: POLARIZATION
PHENOMENA IN NUCLEAR REACTIONS ((EDS) H.H. BARSHALL AND
W. HAEBERLI), P. 682, THE UNIVERSITY OF WISCONSIN PRESS.
(1971).
9) GILBERT, A. AND CAMERON, A.G.W.: CAN. J. PHYS., 43, 1446
(1965).
10) IIJIMA, S., ET AL.: J. NUCL. SCI. TECHNOL. 21, 10 (1984).
11) GRUPPELAAR, H.: ECN-13 (1977).
12) ENSDF: EVALUATED NUCLEAR STRUCTURE DATA FILE (JUNE 1987).
13) NUCLEAR DATA SHEETS, 36, 227 (1982).
14) BENZI, V. AND REFFO, G.: CCDN-NW/10 (1969).
15) KIKUCHI, K. AND KAWAI, M.: "NUCLEAR MATTER AND NUCLEAR
REACTIONS", NORTH HOLLAND (1968).