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97-Bk-250 JAERI EVAL-MAR87 T.NAKAGAWA JAERI-M 88-004 DIST-JAN09 20090105 ----JEFF-311 MATERIAL 9755 -----INCIDENT NEUTRON DATA ------ENDF-6 FORMAT *************************** JEFF-3.1.1 ************************* ** ** ** Original data taken from: JEFF-3.1 ** ** ** ****************************************************************** ***************************** JEFF-3.1 ************************* ** ** ** Original data taken from: JEFF-3.0 ** ** ** ****************************************************************** ***************************** JEFF-3.0 *********************** DATA TAKEN FROM :- JENDL-3.2 (DIST-SEP89) ****************************************************************** HISTORY 87-03 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 A. Nouri (NEA Data Bank) MT = 452 was not equal to the sum of MT = 455 and 456 Redefine MT = 452 in tabular format (LNU = 2) as real sum of MT = 455 and 456 MT=455 DELAYED NEUTRON DATA BASED ON SEMI-EMPIRICAL FORMULA BY TUTTLE /2/. A. Nouri (NEA Data Bank) Redefine MT = 455 in tabular format (LNU = 2) MT=456 NUMBER OF PROMPT NEUTRONS PER FISSION BASED ON SEMI-EMPIRICAL FORMULA BY HOWERTON /3/. MF=2,MT=151 RESONANCE PARAMETERS RESOLVED RESONANCE PARAMETERS (MLBW) : 1.0E-5 EV TO 100 EV RESONANCE PARAMETERS WERE HYPOTHETICALLY GENERATED ADOPTING THE FOLLOWING AVERAGE VALUES. D-OBS = 2.09 EV (FROM LEVEL DENSITY PARAMETERS ) S0, S1= 0.83E-4, 3.37E-4 (FROM OPTICAL MODEL CALC.) RADIATIVE WIDTH = 0.035EV (SAME AS CF-252) FISSION WIDTH = 0.095 EV (ASSUMED THAT THE RATIO OF FISSION TO RADIATIVE WIDTH IS EQUAL TO CROSS SECTION RATIO) THE ENERGY OF FIRST LEVEL WAS ADJUSTED TO REPRODUCE THE 2200-M/S CROSS SECTIONS OF 350 BARNS /4/ AND 960 BARNS /5/ FOR CAPTURE AND FISSION, RESPECTIVELY. UNRESOLVED RESONANCES : 0.1 TO 30 KEV BY ADOPTING PARAMETERS USED FOR RESOLVED RESONANCE GENERATION AS INITIAL VALUES, THEY WERE ADJUSTED TO REPRODUCE THE EVALUATED FISSION AND CAPTURE CROSS SECTIONS BY USING ASREP /6/. FINAL VALUES OF THE PARAMETERS ARE, S0 = 0.82E-4, S1 = 3.9E-4, D-OBS = 2.09 EV, RADIATIVE WIDTH = 0.035 EV, R =9.02 FM, FISSION WIDTH = 0.104 EV AT 100 EV, 0.208 EV AT 30 KEV. CALCULATED 2200 M/S CROSS SECTIONS AND RESONANCE INTEGRALS 2200 M/S VALUE RES. INT. TOTAL 1325.0 B - ELASTIC 12.22 B - FISSION 959.3 B 517. B CAPTURE 353.4 B 199. B MF=3 NEUTRON CROSS SECTIONS 1) THE OPTICAL MODEL CALCULATION WAS PERFORMED WITH CODE CASTHY /7/. OPTICAL POTENTIAL PARAMETERS USED WERE OBTAINED /8/ BY FITTING THE TOTAL CROSS SECTION MEASURED BY PHILLIPS AND HOWE /9/ FOR AM-241: V = 43.4 - 0.107*EN (MEV) WS= 6.95 - 0.339*EN + 0.0531*EN**2 (MEV) (IN THE DERIVATIVE WOODS-SAXON FORM) WV= 0 , VSO = 7.0 (MEV) R = RSO = 1.282 , RS = 1.29 (FM) A = ASO = 0.60 , B = 0.5 (FM) 2) IN THE STATISTICAL CALCULATION, THE FISSION, (N,2N), (N,3N) AND (N,4N) CROSS SECTIONS WERE CONSIDERED AS THE COMPETING PROCCESS CROSS SECTIONS. 3) THE LEVEL DENSITY PARAMETERS WERE DERIVED FROM RESONANCE LEVEL SPACINGS AND LOW LAYING EXCITED LEVELS ON THE BASIS OF GILBERT-CAMERON'S FORMULA /10/. ----------------------------------------------------------- ISOTOPE 247 248 249 250 251 ----------------------------------------------------------- A(1/MEV) 28.1 27.8 34.2 30.05 30.0 SPIN-CUTOFF FACT 30.47 30.39 33.79 31.76 31.82 PAIRING E(MEV) 0.39 0.0 0.903 0.0 0.865 TEMP.(MEV) 0.364 0.326 0.366 0.340 0.385 C(1/MEV) 2.90 10.8 12.2 24.6 6.56 EX(MEV) 7.97 1.85 4.30 2.34 4.05 ----------------------------------------------------------- BELOW 30 KEV, CROSS SECTIONS ARE REPRESENTED WITH RESONANCE PARAMETERS. MT=1,2 TOTAL AND ELASTIC SCATTERING THE OPTICAL MODEL CALCULATION WAS ADOPTED. MT=4, 51 TO 59 AND 91 INELASTIC SCATTERING THE LEVEL SCHEME WAS TAKEN FROM REF. /11/. NO. ENERGY(KEV) SPIN-PARITY -------------------------------------------- GROUND 0.0 2 - 1 34.5 3 - 2 35.6 4 + 3 78.1 5 + 4 86.4 7 + 5 97.0 5 - 6 104.1 1 - 7 125.4 2 - 8 129.0 6 + 9 131.9 3 + 10 157.0 8 + 11 167.0 6 - 12 175.4 1 + 13 191.0 7 + 14 211.8 2 + 15 237.0 3 + 16 242.0 9 + 17 248.0 7 - 18 270.0 4 + -------------------------------------------- LEVELS ABOVE 296 KEV WERE ASSUMED TO BE OVERLAPPING. MT=16, 17 AND 37 (N,2N), (N,3N) AND (N,4N) CALCULATED WITH EVAPORATION MODEL BY TAKING THE COMPOUND NUCLEUS FORMATION CROSS SECTION CALCULATED WITH OPTICAL MODEL. MT=18 FISSION SHAPE OF THE CF-251 FISSION CROSS SECTION /12/ WAS ADOPTED AND MULTIPLIED BY THE FACTOR OF 0.84. MT=102 RADIATIVE CAPTURE CALCULATED WITH CASTHY. THE AVERAGE RADIATIVE WIDTH OF 0.035 EV AND S-WAVE LEVEL SPACING OF 2.09 EV WERE ASSUMED. MT=251 MU-BAR CALCULATED WITH CASTHY. MF=4 ANGULAR DISTRIBUTIONS OF SECONDARY NEUTRONS MT=2,51-59 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 ASSUMED. MT=18 MAXWELLIAN FISSION SPECTRUM. TEMPERATURE ESTIMATED FROM SYSTEMATICS OF SMITH ET AL./13/. REFERENCES 1) NAKAGAWA, T.: JAERI-M 88-004 (1987). 2) TUTTLE, R.J.: INDG(NDS)-107/G+SPECIAL, P.29 (1979). 3) HOWERTON, R.J.: NUCL. SCI. ENG., 62, 438 (1977). 4) MUGHABGHAB, S.F.: NEUTRON CROSS SECTIONS, VOL.1, PART B, ACADEMIC PRESS (1984) 5) DIAMOND, H., ET AL.: J. INORG. NUCL. CHEM., 30, 2553 (1968). 6) IGARASI, S.: J. NUCL. SCI. TECHNOL., 12, 67 (1975). 7) KIKUCHI, Y.: PRIVATE COMMUNICATION. 8) IGARASI, S. AND NAKAGAWA T.: JAERI-M 8342 (1979). 9) PHILLIPS, T.W. AND HOWE, F.R.: NUCL. SCI. ENG., 69, 375(1979). 10) GILBERT A. AND CAMERON A.G.W. : CAN. J. PHYS., 43, 1446(1965). 11) SCHMORAK, M.R.: NUCL. DATA SHEETS, 32, 87 (1981). 12) NAKAGAWA, T: JAERI-M 86-086 (1986). 13) SMITH, A.B. ET AL.: ANL/NDM-50 (1979).Back |