94-Pu-239
94-PU-239 NAIG EVAL-MAR87 M.KAWAI, T.YOSHIDA, K.HIDA
DIST-MAR02 REV4-MAR00 20020214
----JENDL-3.3 MATERIAL 9437
-----INCIDENT NEUTRON DATA
------ENDF-6 FORMAT
HISTORY
87-03 Evaluation was made by
M.Kawai and K.Hida(naig) : cross sections above
resonance region and other quantities,
T.Yoshida(naig) : resonance parameters and background
cross sections,
Data were compiled by T.Nakagawa (jaeri).
88-08 Partly modified.
Nu-bar, resolved resons., (n,2n).
89-02 FP yields were taken from JNDC FP decay data file version-2.
89-03 Unresolved resonance parameters were slightly modified.
93-02 JENDL-3.2.
Resonance parameters evaluated by H.Derrien (jaeri)/1/.
Fission spectra calculated by T.Ohsawa (kinki univ.)
Compiled by T.Nakagawa (ndc/jaeri)
***** modified parts for JENDL-3.2 ********************
(2,151) Resolved resonance parameters up to 2.5 keV
(5,18)
***********************************************************
2000-03 JENDL-3.3 compiled by K.Shibata (jaeri)
***** modified parts for JENDL-3.3 ********************
(1,451), (1,455), (2,151), (3,2), (3,18), (3,102),
(5,16), (5,17), (5,91), (5,455)
************************************************************
2000-05 Fission spectra were re-evaluated by T.Ohsawa (Kinki U.).
JENDL-3.2 was adopted at 14 and 20 MeV.
2001-06 Fission spectra were replaced with the calculations by
Kawano et al./2/ above 10 MeV.
2002-01 Covariances were taken from JENDL-3.2 covariance file
except for mf/mt=3/18.
mf=1 General information
mt=451 Descriptive data and dictionary
mt=452 Number of neutrons per fission
Sum of nu-p (mt=456) and nu-d (mt=455).
mt=455 delayed neutron data
Evaluated data by Tuttle /3/ were adopted.
Decay constants were adopted from Keepin et al./4/
mt=456 Number of prompt neutrons per fission
Standard Cf-252 sf nu-p was taken to be 3.756. Thermal nu-p
was 2.8781 that was a mean value of experimental data. The
energy dependent nu-p was obtained from
below 10 eV : ref./5/ multiplied by 1.001
10 eV 8 MeV
Ws = 3.6 + 0.4*En (MeV), En < 7 MeV
6.4 + 0.1*(En-7) (MeV), En > 7 MeV
Vso = 6.2 (mev)
r: rv = 1.26 , rs= 1.24 rso= 1.12 (fm)
a: av = 0.615, as= 0.50 , aso= 0.47 (fm)
beta-2= 0.21, beta-4= 0.065
The compound component was calculated with optical and
statistical model code casthy /21/, taking into account
level fluctuation and interference effects. The fission,
(n,2n), (n,3n), and (n,4n) reactions were considered as
competing processes.
The neutron transmission coefficients for the incident
channel were generated with ecis, whereas those for the exit
channel were calculated with casthy using spherical optical
potential parameters adopted for JENDL-2 evaluation:
V = 40.72 - 0.05*En (MeV)
Ws = 6.78 - 0.29*En (MeV)
Vso= 7.0 (MeV)
r = rso= 1.32, rs =1.357 (fm)
a = aso= b = 0.47 (fm)
The surface absorption is of derivative Woods-Saxon type.
The level scheme was taken from ref./22/:
no. energy(keV) spin-parity coupled level
g.s. 0.0 1/2 + *
1 7.86 3/2 + *
2 57.28 5/2 + *
3 75.71 7/2 + *
4 163.76 9/2 + *
5 194. 11/2 + *
6 285.46 5/2 +
7 317. 13/2 + *
8 330.13 7/2 +
9 360. 15/2 + *
10 387.41 9/2 +
11 391.6 7/2 -
12 435. 9/2 -
13 462. 11/2 +
14 469.8 1/2 -
15 488. 11/2 -
16 492.1 3/2 -
17 505.5 5/2 -
18 511.84 7/2 +
Continuum levels were assumed above 538 keV.
mt= 16, 17, 37 (n,2n), (n,3n), and (n,4n)
Calculated with a modified version of gnash /23/. The
neutron transmission coefficients were generated with ecis
/19/ and optical model code eliese-3 /24/, respectively,
using the above-mentioned deformed and spherical potentials.
The level schemes for pu-236, -237, -238, -239 and -240 were
taken from refs. /22,25,26,27,28/. The Gilbert-Cameron's
composite formula /29/ was used to represent the level
density. Level density parameters were determined from the
observed s-wave resonance spacing /30/ and the level schemes.
the spin cut-off factors in the constant temperature model
were represented by Gruppelaar's prescription /31/.
pu-236 pu-237 pu-238 pu-239 pu-240
a (1/MeV) 25.50 28.00 26.23 29.44 26.96
t (MeV) 0.442 0.416 0.422 0.398 0.412
c (1/MeV) 3.06 14.5 2.88 15.0 3.30
E-joint(MeV) 4.71 4.09 4.38 3.97 4.26
sigma**2 8.63 8.18 6.47 11.6 9.69
no. levels 4.0 19.0 22.0 19.0 28.0
E-max (MeV) 0.307 0.4735 1.3103 0.5118 1.2621
D-obs (eV) 0.395 10.7 0.383 9.0 2.3
Gamma-g(eV) 0.043 0.027 0.043 0.034 0.043
D-obs of pu-236, -237 and -238 were not available from ref.
/30/, and hence the parameters "a" for these nuclei were
determined assuming its linear dependence on the mass a:
a = 0.365*a - 60.64 for even-even pu isotopes
a = 0.659*a - 128.18 for odd-mass pu isotopes
which were derived by analyzing the data of pu-241, -242,
-243, and -244 as well as pu-239 and -240. Low-lying levels
were hardly observed for pu-236 and it was assumed to be
identical to that of pu-238 to determine the constant
temperature parameters.
Evaluated fission cross section described below was fed to
gnash as a competing process/32/. The preequilibrium process
was taken into account. Though the parameter f2 was
adjusted, the calculated (n,2n) cross section failed to well
reproduce the measured data. Therefore, the measured (n,2n)
cross section of Frehaut et al./33/ was adopted in place of
the calculated one.
mt=18 Fission
Below 30 keV
Based on measurements of ref./34/ and ref./35/.
Above 30 keV
New simultaneous evaluation was performed by
Kawano et al./36/
mt=102 Capture
The cross section in the energy range below 1 MeV was derived
as a product of the evaluated fission cross section and alpha
value. The alpha values are identical to those of JENDL-2.
Above 1 MeV the results of the statistical model calculation
with casthy /21/ linked with ecis /19/ were adopted. The
photon strength function was normalized in the casthy
calculation so as to reproduce the capture cross section of
280 mb at 100 keV.
Direct and semi-direct calculations were performed by Kawano
/37/ above 500 keV.
mf=4 Angular distributions of secondary neutrons
mt=2,51-68,91 Calculated with ecis /19/ and casthy /21/.
mt=16,17,18,37 Isotropic in the laboratory system.
mf=5 Energy distributions secondary neutrons
mt=16,17,37,91
Calculated with threshold cross section calculation code
pegasus /38/ on the basis of preequilibrium and multi-step
evaporation model.
Data for mt=16,17,91 were replaced with gnash calculations
performed by Kawano/37/.
mt=18
Distributions were calculated with a modified Madland-Nix
model with consideration for multimodal nature of the fission
process/39,40/. The compound nucleus formation cross sec-
tions for fission fragments were calculated using Becchetti-
Greenlees potential/41/. Up to 3rd-chance-fission were
considered at high incident neutron energies.
A preequilibrium emission was taken into account above 10 MeV
as described in Ref./2/. The prefission neutron spectrum
was calculated with the Feshbach-Kerman-Koonin theory /42/.
The Ignatyuk formula/43/ were used to generate the level
density parameters.
Parameters adopted for thermal-neutron fission/40/:
(S1: standard-1, S2: standard-2, S3: standard-3 modes)
total average fragment kinetic energy
= 190.4 MeV for S1
= 174.2 MeV for S2
= 164.2 MeV for S3
average energy release = 205.400 MeV for S1
= 196.279 MeV for S2
= 182.123 MeV for S3
average mass number of light ff = 105 for S1
= 99 for S2
= 83 for s3
average mass number of heavy ff = 135 for S1
= 141 for S2
= 157 for s3
level density of the light ff = 11.236(S1),
10.764(S2), 6.669(S3)
level density of the heavy ff = 9.577(S1),
13.104(S1),16.284(S3)
mode branching ratio = 0.248(S1), 0.742(S2), 0.01(S3)
These data are essentially based on Schillebeeckx et al.
/44/.
Note that the parameters vary with the incident energy.
Energy-dependent mode branching ratio data of Brosa et al.
/45/ was used.
mt=455
Taken from Brady and England /46/. Group abundance parameters
were adjusted so as to reproduce total delayed neutron
emission rate measured by Keepin et al./4/, Besant et al.
/47/ and Maksyutenko /48/
mf=12 Photon production multiplicities and transition
probability arrays
mt=16,17,37,91,102 (n,2n),(n,3n),(n,4n),inelastic scattering
to the continuum, and capture
Data calculated with gnash /23/ were stored under option-1
(multiplicities). The photon branching data were taken from
refs. /22/ and /25,26,27,28/. Some assumptions were made
for levels of pu-237 and -239 which had no information on
branching: if e1 transitions were allowed to lower levels,
the transition probabilities were equally shared among them.
If not, equally shared collective E2 transitions were
assumed. The photon strength functions were represented by
the Brink-Axel type giant dipole resonance with conventional
resonance positions and widths. They were normalized to
input values at the thermal energy. The pygmy resonance was
introduced only for pu-240. The parameters were assumed to
be the same as those of u-238 /49/.
mt=18 Fission
Stored under option-1 (multiplicities). The thermal neutron
induced fission gamma spectrum measured by Verbinski /50/
was adopted and used up to 20 MeV neutron. Since no data
were given for the photons below 0.14 MeV, it was assumed to
be the same as that of the photons between 0.14 and 0.3 MeV.
mt=51-68 Inelastic scattering
Stored under option-2 (transition probability arrays). Data
were taken from ref./22/, and the same assumptions as
described above were applied to the levels to which no data
were given.
mf=14 Photon angular distributions
mt=16,17,18,37,51-68,91,102 Isotropic.
mf=15 Continuous photon energy spectra
mt=16,17,37,91,102 Calculated with gnash /23/
mt=18 Experimental data by Verbinski /50/
were adopted.
mf=31 Covariances of average number of neutrons per fission
mt=452
Constructed from mt=455 and 456.
mt=455
Based on experimental data. A chi-value was 0.46.
mt=456
Based on experimental data. A chi-value was 1.16.
mf=32 Covariances of resonance paremeters
mt=151
Resolved resonance
The covariances were obtained by using kalman./51/
Unresolved resonance
The covariances were obtained by using kalman./52/
mf=33 Covariances of cross sections (ref.43)
mt=1
Based on experimental data. A chi-value was 1.29.
mt=2
Constructed from mt=1, 4, 16, 17, 18, 37, and 102.
mt=4, 51-68, 91
The covariances were obtained by using kalman /52/.
A chi-value was 1.66.
mt=16
Based on experimental data. A chi-value was 1.0.
mt=17
Systematics.
mt=18
Based on simultaneous evaluation /36/.
mt=37
Systematics.
mt=102
Based on experimental data. A chi-value was 0.47.
mf=34 Covariances of angular distributions (ref.52)
mt=2
The covariances of p1 coefficients were obtained by using
kalman. A chi-value was 0.41.
mf=35 Covariances of energy distributions
mt=18
The covariances were obtained by using kalman./53/
References
1) Derrien H.: J. Nucl. Sci. Technol., 30, 845 (1993).
2) Kawano T. et al.: Phys. Rev., C63, 034601 (2001).
3) Tuttle R.J.: INDC(NDS)-107/G + special, 29 (1980).
4) Keepin G.R. et al.: Phy. Rev., 107, 1044 (1957).
5) Gwin R. et al.: Nucl. Sci. Eng., 94, 365 (1986).
6) Frehaut J.: NEANDC(E)-238/L (1986).
7) Gwin R. et al.: Nucl. Sci. Eng., 87, 381 (1984).
8) Soleilhac M. et al.: 70 Helsinki , 2, 145 (1970).
9) Soleilhac M. et al.: J. Nucl. Energy. 23. 257 (1969).
10) Nurpeisov B. et al.: At. Energiya, 39, 199 (1975).
11) Vorodin K.E. et al.: At. Energiya. 33. 901 (1972).
12) Nakagawa T.: Private communication (2000).
13) Uttely C.A.: EANDC(UK)-40 (1964).
14) Schwartz R.B. et al.: Nucl. Sci. Eng., 54, 322 (1974).
15) Foster D.G.Jr. and Glagow D.W.: Phys. Rev., C3, 576 (1971).
16) Smith A.B. et al.: J. Nucl. Energy, 27, 317 (1973).
17) Nadolny et al.: C00-3058-39, 33 (1973).
18) Poenitz W.P. et al.: Nucl. Sci. Eng., 78, 333 (1981).
19) Raynal J.: IAEA SMR-9/8 (1970).
20) Arthur E.D. et al.: Nucl. Sci. Eng. 88, 56 (1984).
21) Igarasi S. and Fukahori T.: JAERI 1321 (1991).
22) Schmorak M.R.: Nucl. Data Sheets, 40, 1 (1983).
23) Young P.G. et al.: LA-6947 (1977).
24) Igarasi S.: JAERI-1224 (1972).
25) Schmorak M.R.: Nucl. Data Sheets, 36, 367 (1982).
26) Ellis-Akovali Y.A.: Nucl. Data Sheets, 49, 181 (1986).
27) Shurshikov E.N.: Nucl. Data Sheets, 38, 277 (1983).
28) Shurshikov E.N. et al.: Nucl. Data Sheets, 43, 245 (1984).
29) Gilbert A. et al.: Can. J. Phys. 43, 1446 (1965).
30) Mughabghab S.F.: Neutron Cross Sections, Vol 1, Part B (1984).
31) Gruppelaar H.: ECN-13 (1977).
32) Yamamuro N. et al.: JAERI-M 87-025, 347 (1987).
33) Frehaut J. et al.: CEA-N-2500 (1986).
34) Gayther D.B.: 1975 Washington, 2, 560 (1975).
35) Wagemans C. et al.: Ann. Nucl. energy, 7, 495 (1980).
36) Kawano T. et al.: JAERI-Research 2000-004 (2000).
37) Kawano T.: Private communication (1999).
38) Iijima S. et al.: JAERI-M 87-025, p.337 (1987).
39) Madland D.G. and Nix J.R.: Nucl. Sci. Eng., 81, 213 (1982).
40) Ohsawa, T. et al.: Nucl. Phys. A665, 3 (2000).
41) Becchetti Jr.F.D. and Greenlees G.W.: Phys. Rev., 182, 1190
(1969).
42) Feshbach H., et al.: Ann. Phys. (N.Y.) 125, 429 (1980).
43) Ignatyuk A.V.: Sov. J. Nucl. Phys., 29, 450 (1979).
44) Schillebeeckx P. et al.: Nucl. Phys. A545, 623 (1992).
45) Brosa U. et al.: Phys. Rev. C59, 767 (1999).
46) Brady M.C. and England T.R.: Nucl. Sci. Eng., 103, 129 (1989).
47) Besant C.B. et al.: J. Br. Nucl. Energy Soc., 16, 161
(1977)
48) Maksyutenko B.P.: Yad. Fiz. (English Translation) 15,
848 (1963)
49) Hida K.: JAERI-M 85-035, 166 (1985).
50) Verbinski V.V. et al.: Phys. Rev., C7, 1173 (1973).
51) Kawano T.: Private communication (2000).
52) Shibata K. et al.: JAERI-Research 97-074 (1997).
53) Kawano T. et al.: JAERI-Research 99-009 (1999).
=================================================================
APPENDIX RESONANCE DATA
=================================================================
THE PRESENT FILE CONTAINS THE RESONANCE PARAMETERS OBTAINED
FROM A SAMMY FIT ANALYSIS OF HIGH RESOLUTION EXPERIMENTAL DATA,
PERFORMED AT ORNL(OAK RIDGE NATIONNAL LABORATORY,USA) BY H.DERRIEN
AND G.DE SAUSSURE AND AT JAERI(TOKAI-MURA RESEARCH ESTABLISHMENT,
JAPAN) BY H.DERRIEN.
THE FILE CONTAINS THREE INDEPENDANT SECTIONS:
1/ THE FIRST CORRESPONDS TO THE ENERGY RANGE 0 KEV TO 1 KEV.
THE CORRESPONDING SET OF RESONANCE PARAMETRES CONTAINS 398 RESO-
NANCES IN THE ENERGY RANGE 0 KEV TO 1 KEV, 4 FICTICIOUS NEGATIVE
ENERGY RESONANCES AND 3 FICTICIOUS RESONANCES ABOVE 1 KEV;
2/ THE SECOND CORRESPONDS TO THE ENERGY RANGE 1 KEV TO 2 KEV.
THE CORRESPONDING SET OF RESONANCE PARAMETERS CONTAINS 435 RESON-
ANCES IN THE ENERGY RANGE 0.980 KEV TO 2.02 KEV, 3 FICTICIOUS
RESONANCES BELOW 0.9 KEV AND 3 FICTICIOUS RESONANCES ABOVE 2.02
KEV;
3/ THE THIRD CORRESPONDS TO THE ENERGY RANGE 2 KEV TO 2.5 KEV.
THE CORRESPONDING SET OF RESONANCE PARAMETERS CONTAINS 218 RESO-
NANCES IN THE ENERGY RANGE 1.98 KEV TO 2.53 KEV, 3 FICTICIOUS
RESONANCES BELOW 1.98 KEV AND 3 FICTICIOUS RESONANCES ABOVE 2.53
KEV.
IN ALL SECTIONS THE FICTICIOUS RESONANCE PARAMETERS TAKE INTO
ACCOUNT THE CONTRIBUTION OF ALL THE EXTERNAL TRUNCATED RESONANCES
IN SUCH A WAY THAT NO TOTAL, SCATTERING, FISSION AND CAPTURE
SMOOTH FILES ARE NEEDED IN THE CORRESPONDING ENERGY RANGES FOR THE
REPRODUCTION OF THE CROSS SECTIONS WITHIN THE EXPERIMENTAL ERRORS.
THE FOLLOWING EXPERIMENTAL DATA BASE HAS BEEN USED IN THE SAMMY
FITS:
-ABSORPTION AND FISSION FROM R.GWIN ET AL./1,2/;
-FISSION FROM R.GWIN ET AL./3,4/, J.BLONS/5/, L.W.WESTON ET
AL./6,7/;
-TRANSMISSION FROM R.R.SPENCER ET AL./8/, J.A.HARVEY ET AL./9/
PRIOR TO THE FITS THE EXPERIMENTAL FISSION AND ABSORPTION CROSS
SECTIONS WERE NORMALISED, DIRECTLY OR INDIRECTLY TO THE 0.0253 EV
VALUES OBTAINED BY THE ENDF/B-VI STANDARD EVALUATION GROUP/10/.
THE TRANSMISSION DATA WERE CONSIDERED AS ACCURATE ABSOLUTE MEASU-
REMENTS(R.R.SPENCER TOTAL CROSS SECTION AT 0.0253 EV IS 1025.0 B
IN EXCELLENT AGREEMENT WITH THE 1027.3 B STANDARD VALUE).
DETAILS ON THE ANALYSIS ARE FOUND IN REFERENCES/11,12,13/
*****************************************************************
COMMENTS ON THE THERMAL AND LOW ENERGY RANGES
*****************************************************************
THE THERMAL CROSS SECTION VALUES CALCULATED AT 293 K BY THE
RESONANCE PARAMETERS OF THE FIRST SECTION ARE GIVEN IN THE FOLLO-
WING TABLE:
SAMMY RESENDD PROPOSED
293 K (BARN) STANDARD VALUES(BARN)/10/
****************************************************************
FISSION 747.64 747.90 747.99+-1.87
CAPTURE 271.10 270.73 271.43+-2.14
SCATTERING 7.97 7.99 7.88+-0.97
TOTAL 1026.71 1026.62 1027.30+-5.00
****************************************************************
ONE SHOULD NOTE THAT THE 293 K CROSS SECTIONS CALCULATED AT
0.0253 EV DEPEND ON THE WAY THE DOPPLER BROADENING CALCULATION IS
PERFORMED. FOR INSTANCE USING A GAUSSIAN BROADENING FUNCTION WILL
GIVE A FISSION CROSS SECTION ABOUT 2.5 BARNS LARGER THAN THE ONE
OBTAINED FROM THE ACCURATE CALCULATION WHICH CONSERVES THE 1/V
SHAPE OF THE THERMAL CROSS SECTION. THE VALUES GIVEN IN THE TABLE
ABOVE WERE OBTAINED FROM SAMMY (LEAL-HWANG METHOD)/14,15/ AND FROM
RESENDD WITH 0.1% FOR THE INTERPOLATION ACCURACY/16/.
THE FOLLOWING TABLE SHOWS EXPERIMENTAL CROSS SECTIONS AVE-
RAGED OVER THE ENERGY RANGES 0.02 EV TO 0.06 EV AND 0.02 EV TO
0.65 EV, COMPARED TO THE CALCULATED VALUES:
AVERAGE CROSS-SECTIONS(BARN)
****************************************************************
REFERENCES(1-10) 0.02 TO 0.06 EV 0.02 TO 0.65 EV
****************************************************************
EXP CALC (293K) EXP CALC (293K)
GWIN71 FISS 631.41 843.71
GWIN76 FISS 631.41 838.39
GWIN84 FISS(*) 631.41 631.75(+0.05%) 837.18 838.69(+0.18%)
DERUYTER70 FISS 631.41 859.43
WAGEMANS80 FISS 631.41 862.56
WAGEMANS88 FISS 631.41 841.80
GWIN71 CAPTURE 243.84 243.22(-0.25%) 524.75 518.13(-1.26%)
GWIN76 ABSORPT(*) 875.90 874.29(-0.18%) 1359.96 1357.14(-0.21%)
SPENCER84 TOT(*) 883.20 882.86(-0.04%) 1361.69 1367.6 (+0.43%)
****************************************************************
(*)THESE DATA HAD THE LARGIEST WEIGHT IN THE THERMAL FIT. THE VA-
LUES BETWEEN THE PARENTHESES GIVE THE PERCENTAGE DEVIATION BETWEEN
THE CALCULATED DATA AND THE EXPERIMENTAL DATA.
*****************************************************************
THE VALUE OF 631.4 BARNS FOR ALL THE AVERAGED EXPERIMENTAL
FISSION CROSS SECTIONS IN THE ENERGY RANGE 0.02 EV TO 0.06 EV
CORRESPONDS TO THE RENORMALISATION OF THE FISSION EXPERIMENTS TO
748.0+-1. BARNS AT 0.0253 EV. ORNL DATA ARE CONSISTENT WITHIN 0.8%
OVER THE ENERGY RANGE 0.02 EV TO 0.65 EV (I.E. OVER THE 0.3 EV
RESONANCE). DERUYTER 1970 AND WAGEMANS 1980 DATA ARE ABOUT 2.5%
LARGER AND WERE NOT INCLUDED IN THE SAMMY FIT. WHEN NORMALIZED ON
THE STANDARD VALUE AT 0.0253 EV, GWIN 76 ABSORPTION AGREES WITH
THE ABSORPTION OBTAINED FROM SPENCER TOTAL CROSS SECTION WITHIN
0.7% OVER THE 0.3 EV RESONANCE. THE PRESENT EVALUATION IS
ESSENTIALLY THE RESULT OF A CONSISTENT SAMMY ANALYSIS OF ALL THE
AVAILABLE ORNL DATA WITH A LARGER WEIGHT ON GWIN 1984 FISSION,
GWIN 1976 ABSORPTION AND SPENCER TRANSMISSION DATA.
AFTER RENORMALIZATION OF THE CALCULATED FISSION CROSS SECTION
ON THE PRELIMINARY 1991 WESTON AND TODD FISSION DATA(SEE NEXT
SECTION) A SLIGHT ADJUSTMENT OF THE NEGATIVE RESONANCE PARAMETERS
WAS PERFORMED TO KEEP THE VALUES CALCULATED AT 0.0253 EV IN CLOSE
AGREEMENT WITH THE STANDARD VALUES. THE 1988 DATA OF WAGEMANS ET
AL./17/ AGREE WITHIN 0.4% WITH THE CALCULATED VALUES OVER THE
ENERGY RANGE FROM 0.02 EV TO 0.65 EV AFTER ADJUSTMENT OF THE
ENERGY SCALE TO THE ORNL SCALE (THE DIFFERENCE WAS 0.27 EV AT 20
EV BETWEEN 1988 WAGEMANS AND ORNL SAMMY FIT ENERGY SCALES).
*****************************************************************
COMMENTS ON THE 0 KEV TO 1 KEV ENERGY RANGE.
*****************************************************************
AT THE END OF 1987, AN ANALYSIS WAS COMPLETED UP TO 1 KEV. IN A
PRELIMINARY STEP, A CORRELATED FIT OF HARVEY TRANSMISSION DATA,
WESTON 84 FISSION DATA AND BLONS FISSION DATA WAS PERFORMED, WITH
POSSIBLE ADJUSTMENT OF THE NORMALIZATION COEFFICIENTS AND OF THE
BACKGROUND CORRECTIONS. THIS PRELIMINARY STEP HAS SHOWN THAT THIS
ADJUSTMENT WAS NOT NECESSARY TO HAVE CONSISTENCY BETWEEN HARVEY
DATA AND WESTON DATA. BLONS DATA NEEDED A LARGE READJUSTMENT OF
THE BACKGROUND AND OF THE NORMALIZATION. THEREFORE, THE FINAL FIT
WAS PERFORMED ONLY ON HARVEY TRANSMISSION DATA, GWIN 84 FISSION
DATA (BELOW 30 EV) AND WESTON 84 FISSION DATA, WITH NO BACKGROUND
AND NORMALISATION ADJUSTMENT. BLONS DATA, WHICH HAVE BETTER
RESOLUTION THAN WESTON 84 DATA, WERE USED ONLY TO OBTAIN MORE
ACCURATE FISSION WIDTHS OF SOME NARROW RESONANCES IN THE HIGH
ENERGY RANGE.
IN 1989, PRELIMINARY RESULTS OF THE 1988 WESTON FISSION
MEASUREMENT/7/ WERE INCLUDED IN THE SAMMY EXPERIMENTAL DATA
BASE. ONE EXPECTED FROM THIS MEASUREMENT, WHICH WAS PERFORMED BY
USING A 86 M FLIGHT PATH WITH A RESOLUTION COMPARABLE TO THE
RESOLUTION OF HARVEY TRANSMISSION, A CONFIRMATION OF THE EXCELLENT
QUALITY OF THE 1984 MEASUREMENT. A CONSISTENT SAMMY FIT OF HARVEY
TRANSMISSION, WESTON 84 FISSION AND PRELIMINARY WESTON 88 FISSION
WAS RESTARTED FROM THE PARAMETER AND COVARIANCE FILES OBTAINED IN
1987. IT APPEARED THAT LARGE BACKGROUND AND NORMALISATION
CORRECTIONS WERE NEEDED ON THE NEW WESTON FISSION TO OBTAIN
CONSISTENCY WITH HARVEY TRANSMISSION DATA. THESE CORRECTIONS WERE
COMPARABLE TO THOSE FOUND ON BLONS DATA AND WERE NOT UNDERSTOOD BY
THE AUTHORS OF THE EXPERIMENT. THE LAST SAMMY RUNS WERE PERFORMED
BY NOT ALLOWING BACKGROUND AND NORMALIZATION VARIATIONS ON HARVEY
TRANSMISSION AND WESTON 84 FISSION(VERY SMALL ERROR BARS WERE
ASSIGNED TO THE CORRESPONDING PARAMETERS IN THE COVARIANCE MATRIX)
AND BY ALLOWING THESE VARIATIONS ON WESTON 88 DATA. A NEW SET OF
RESONANCE PARAMETERS WAS OBTAINED,WHICH WAS IMPROVED COMPARED TO
THE PREVIOUS SET DUE TO THE VERY HIGH RESOLUTION OF THE NEW WESTON
FISSION MEASUREMENT.
THE CALCULATED AVERAGE FISSION CROSS SECTION IN THE ENERGY
RANGE FROM 0.1 KEV TO 1.0 KEV WAS 3.7% SMALLER THAN THE VALUES
OBTAINED BY THE ENDF/B-VI STANDARD EVALUATION GROUP, DUE TO THE
FACT THAT WESTON 84 DATA WERE 3.1% LOWER THAN THE AVERAGE STANDARD
VALUE. A NEW MEASUREMENT WAS PERFORMED BY WESTON AND TODD IN 1991
/18/ IN ORDER TO CHECK THEIR 1984 DATA. A CAREFUL NORMALIZATION
OF THE DATA IN THE THERMAL ENERGY RANGE SHOWED THAT THE 1984 DATA
SHOULD BE RENORMALIZED BY ABOUT +3%. TO TAKE INTO ACCOUNT THIS
RENORMALIZATION, THE 1989 RESONANCE PARAMETERS WERE MODIFIED AT
JAERI/13/ IN THE FOLLOWING WAY:
1/ INCREASE OF THE FISSION WIDTH BY 3% AND DECREASE OF THE
CAPTURE WIDTH BY A QUANTITY EQUAL TO THE VARIATION OF THE FISSION
WIDTH, IN THE NARROW RESONANCES(MAINLY 1+ RESONANCES); THAT DOES
NOT MODIFY THE TOTAL CROSS SECTION IN THE CORRESPONDING
RESONANCES;
2/ ADJUSTMENT OF THE NEUTRON WIDTH OF THE 0+ RESONANCES BY A
REFIT OF THE TRANSMISSION DATA AND OF THE RENORMALIZED WESTON AND
TODD 1984 DATA IN ENERGY RANGES WHERE THE CONTRIBUTION OF THE 0+
RESONANCES IS DOMINANT, AND INCREASE OF THE OTHER(SMALL) 0+
NEUTRON WIDTHS BY 3%. NO SEVERE INCONSISTENCY WAS OBSERVED BETWEEN
THE TRANSMISSION DATA AND THE NEW FISSION DATA OVER THE DOMINANT
0+ RESONANCES;THE DIFFERENCES BETWEEN THE 1989 FITS OF THE TRANS-
MISSION AND THE NEW FITS WERE CONSISTENT WITHIN THE EXPERIMENTAL
ERROR BARS.
THE FOLLOWING TABLE SHOWS THE FISSION CROSS SECTIONS CALCULA-
TED FROM THE RESONANCE PARAMETERS, THE EXPERIMENTAL VALUES AND THE
RESULTS OF THE ENDF/B-VI STANDARD EVALUATION GROUP AVERAGED IN THE
SAME ENERGY INTERVALS. WESTON 1991 DATA ARE PRELIMINARY. WESTON
1984 DATA ARE NORMALIZED ON PRELIMINARY WESTON 1991:
CROSS-SECTIONS(BARN)
*************************************************
ENERGY CALCUL WESTON WESTON STANDARD
(EV) 1991 1984
*************************************************
0.010-10. 80.12 79.98
9-20 94.74 94.91
20-40 17.52 17.76 17.97
40-60 50.64 50.90 50.87
60-100 54.42 54.38 54.33
100-200 18.63 18.59 18.56 18.66
200-300 17.85 17.89 17.88
300-400 8.31 8.34 8.43
400-500 9.59 9.58 9.57
-------------------------------------------------
200-500 11.92 11.93 11.93 11.96
-------------------------------------------------
500-600 15.39 15.57 15.86
600-700 4.37 4.30 4.46
700-800 5.51 5.53 5.63
800-900 4.84 4.89 4.98
900-1000 8.33 8.38 8.30
-------------------------------------------------
500-1000 7.69 7.73 7.73 7.79
-------------------------------------------------
20-1000 13.09 13.11 13.11
**************************************************
GWIN 1971 AND 1976 ABSORPTION DATA WERE NOT INCLUDED IN THE
SAMMY FIT IN THE ENERGY RANGE ABOVE 1 EV. ACCURATE ABSORPTION
CROSS SECTIONS SHOULD BE CALCULATED FROM THE PARAMETERS OBTAINED
FROM THE ANALYSIS OF THE TRANSMISSION AND FISSION DATA. THE FOLLO-
WING TABLE SHOWS THE CALCULATED AVERAGE VALUES OF THE CAPTURE, AB-
SORPTION AND ALPHA COMPARED TO GWIN 1971 AND GWIN 1976 DATA. THE
CALCULATIONS WERE PERFORMED WITH RESENDD, 1.0 % ACCURACY:
CROSS-SECTIONS(BARN)
*******************************************************
ENERGY(EV) CALC. VALUES (293K) GWIN DATA
*******************************************************
CAPT ABSORP ALPHA ABSORP ALPHA
7.3- 16.0 76.61 196.04 0.64 208.00 0.74(*)
16.0- 37.5 20.51 44.55 0.85 46.50 0.89(*)
37.5- 50.0 48.72 70.00 2.29 83.15 2.96(*)
50.0-100.0 33.60 92.13 0.57 92.84 0.63
100.0-200.0 15.58 34.29 0.83 33.66 0.87
200.0-300.0 15.85 33.68 0.89 34.69 0.94
300.0-400.0 9.69 18.01 1.16 18.31 1.16
400.0-500.0 3.96 13.56 0.41 13.56 0.44
500.0-600.0 10.87 26.30 0.70 26.54 0.72
600.0-700.0 6.53 10.90 1.49 11.57 1.54
700.0-800.0 4.95 10.47 0.90 10.52 0.97
800.0-900.0 3.65 8.50 0.75 9.30 0.82
900.0-999.9 5.06 13.51 0.60 13.23 0.70
******************************************************
(*) GWIN 1971 DATA
IF ONE EXCEPTS THE ENERGY RANGE 37.5-50 EV, THE CALCULATED AB-
SORPTION VALUES AGREE WELL WITH GWIN EXPERIMENTAL DATA; THEY ARE
ON AVERAGE 1.2% LOWER IN THE ENERGY RANGE FROM 50 EV TO 1000 EV.
*****************************************************************
COMMENTS ON THE 1 KEV TO 2 KEV ENERGY RANGE
*****************************************************************
PRELIMINARY RESONANCE PARAMETERS WERE OBTAINED IN 1989 FROM THE
ANALYSIS OF THE HARVEY THICK SAMPLE TRANSMISSION DATA AND OF THE
PRELIMINARY RESULTS OF WESTON 88 FISSION MEASUREMENT. DUE TO LACK
OF TIME, THE MEDIUM AND THIN SAMPLE TRANSMISSION DATA WERE NOT
INCLUDED IN THE SAMMY DATA BASE, AND THE CONTRIBUTION OF THE
TRUNCATED EXTERNAL RESONANCES WAS NOT CAREFULLY INVESTIGATED.
NEVERTHELESS, THE RESULTS WERE USED IN THE ENDF/B-VI FILE, ALONG
WITH A SMOOTH FILE IN ORDER TO AGREE WITH THE AVERAGE VALUES OF A
PREVIOUS ENDF/B-VI EVALUATION (THIS PRELIMINARY SET OF PARAMETERS
WAS CONSIDERED AS MORE USEFUL THAN THE STATISTICAL PARAMETERS IN
THE ENERGY RANGE 1 KEV TO 2 KEV FOR THE CALCULATION OF THE SELF-
SHIELDING FACTORS).
THE ANALYSIS WAS RESTARTED IN APRIL 1991 AT JAERI(TOKAI
RESEARCH ESTABLISHMENT) WITH AN UPDATED VERSION OF SAMMY ADAPTED
BY T.NAKAGAWA TO THE FACOM 780. THE PRELIMINARY SET OF PARAMETERS
OBTAINED AT OAK RIDGE IN 1989 WAS USED AS PRIOR INFORMATIONS TO
START THE SAMMY CALCULATIONS. ALSO PRIOR TO THE ANALYSIS, THE CON-
TRIBUTION OF THE EXTERNAL RESONANCES WAS CALCULATED BY USING THE
SET OF THE 0 KEV TO 1 KEV KNOWN RESONANCES, SHIFTED IN THE ENERGY
RANGES -1 KEV TO 0 KEV, 2 KEV TO 3KEV AND 3 KEV TO 4 KEV; EQUIVA-
LENT CONTRIBUTION WAS OBTAINED BY USING 3 FICTICIOUS RESONANCES
BELOW 1 KEV AND 3 FICTICIOUS RESONANCES ABOVE 2 KEV(SEE DETAILS IN
REF./13/). THE ANALYSIS WAS PERFORMED ON THE THICK AND MEDIUM
SAMPLE TRANSMISSIONS OF HARVEY DATA (THE THIN SAMPLE DATA WAS NOT
USEFUL IN THE HIGH ENERGY RANGE) AND ON THE 1988 FISSION DATA RE-
LEASED BY WESTON AT THE BEGINNING OF 1991/7/. THE DEFINITIVE
SAMMY FITS WERE PERFORMED IN APRIL 1992 AFTER RENORMALIZATION OF
THE 1988 DATA OF WESTON ON THE ENDF/B-VI STANDARD VALUES BETWEEN 1
KEV AND 2 KEV, IN AGREEMENT WITH THE 1991 NEW MEASUREMENTS OF
WESTON AND TODD.
THE AVERAGE CROSS SECTIONS CALCULATED FROM THE RESONANCE
PARAMETERS ARE COMPARED TO THE EXPERIMENTAL VALUES IN THE FOLLO-
WING TABLE:
**************************************************************
CROSS-SECTIONS(BARN)
---------------------------------------------------
TOTAL FISSION CAPTURE
ENERGY -------------- ------------- -------------
KEV CALC(A) EXP(B) CALC(A) EXP(C) CALC(A) EXP(D)
**************************************************************
1.0-1.1 24.47 24.95 5.549 5.581 4.728 5.04
1.1-1.2 22.82 23.10 5.985 6.017 3.757 2.95
1.2-1.3 22.29 22.90 4.601 4.501 4.287 4.00
1.3-1.4 22.63 22.85 6.997 6.997 3.012 2.52
1.4-1.5 20.42 20.95 4.041 4.059 3.450 3.57
1.5-1.6 18.30 18.95 2.564 2.613 3.521 3.89
1.6-1.7 21.82 21.90 3.952 3.955 3.833 4.36
1.7-1.8 21.26 21.35 3.400 3.425 4.091 4.37
1.8-1.9 23.76 23.30 5.178 5.187 3.639 3.14
1.9-2.0 18.48 18.90 2.152 2.180 3.205 4.06
**************************************************************
1.0-2.0 21.63 21.92 4.442 4.446 3.752 3.79
**************************************************************
(A) TOTAL, FISSION AND CAPTURE CROSS SECTIONS CALCULATED BY
RESENDD FROM THE RESONANCE PARAMETERS.
(B) EXPERIMENTAL TOTAL CROSS SECTIONS FROM REFERENCE/19/.
(C) WESTON AND TODD 1988 HIGH RESOLUTION FISSION CROSS SECTIONS
FROM REFERENCE/7/ NORMALIZED TO ENDF/B-VI STANDARD IN THE
ENERGY RANGE FROM 1.0 KEV TO 2.0 KEV.
(D) GWIN 1971 EXPERIMENTAL DATA NORMALIZED TO GWIN 1976 DATA.
**************************************************************
THE DIFFERENCE OF 1.3% BETWEEN THE AVERAGE CALCULATED TOTAL
CROSS SECTION AND THE AVERAGE EXPERIMENTAL CROSS SECTION IN THE
ENERGY RANGE FROM 1.0 KEV AND 2.0 KEV IS MAINLY DUE TO THE METHOD
OF EVALUATING THE TOTAL CROSS SECTION FROM THE EFFECTIVE CROSS
SECTION IN REFERENCE/19/. THE ACCURACY OF THE SAMMY FIT OF THE
EXPERIMENTAL TRANSMISSION DATA IS BETTER THAN 0.5% ON THE CROSS
SECTION. THE CALCULATED FISSION CROSS SECTIONS ARE IN VERY GOOD
AGREEMENT WITH THE EXPERIMENTAL DATA. THE CAPTURE DATA /1/ ARE
AVERAGE VALUES OBTAINED FROM THE DATA AVAILABLE IN THE EXFOR FILE
AND NORMALIZED TO GWIN 1976 AVERAGE VALUES; THERE ARE LARGE
DIFFERENCES BETWEEN THE CALCULATED DATA AND THE EXPERIMENTAL DATA
AVERAGED OVER 0.1 KEV INTERVALS; BUT ON THE INTERVAL FROM 1.0 KEV
TO 2.0 KEV THE AVERAGE VALUES ARE CONSISTENT WITHIN 1.0%.
*****************************************************************
COMMENTS ON THE 2.0 KEV TO 2.5 KEV REGION
*****************************************************************
THIS ENERGY RANGE WAS ALSO ANALYSED AT JAERI /13/. NO
PRELIMINARY SET OF RESONANCE PARAMETERS WAS AVAILABLE PRIOR TO THE
ANALYSIS. MORE THAN 90% OF THE RESONANCES, COMPARED TO THE LOW
ENERGY RANGE, COULD STILL BE IDENTIFIED IN THE TRANSMISSION DATA
BETWEEN 2 KEV AND 2.5 KEV. THEREFORE THE CORRELATED SAMMY ANALYSIS
OF HARVEY TRANSMISSIONS AND WESTON FISSION WAS STILL FEASIBLE IN
THIS ENERGY RANGE. THE RESONANCE PARAMETERS OBTAINED ARE
CONSISTENT AND HAS NEARLY THE SAME STATISTICAL PROPERTIES AS THOSE
OF THE RESONANCES IN THE 0 TO 2 KEV ENERGY RANGE. A QUITE GOOD FIT
OF THE TRANSMISSION AND FISSION DATA WAS OBTAINED WITHOUT
BACKGROUND AND NORMALISATION ADJUSTMENT. HOWEVER, THE CALCULATED
FISSION CROSS SECTIONS ARE, ON AVERAGE, 1.4% LOWER THAN THE
EXPERIMENTAL VALUES. THIS DIFFERENCE,WHICH HOWEVER IS NOT LARGER
THAN THE SYSTEMATIC ERRORS ON THE EXPERIMENTAL DATA, COULD BE DUE
TO THE DIFFICULTIES OF IDENTIFYING THE WIDE J=0+ RESONANCES IN THE
EXPERIMENTAL DATA, BECAUSE THE EFFECTS OF THE INCREASING
RESOLUTION AND DOPPLER WIDTHS. PRIOR TO THE SAMMY FITS, THE
FISSION DATA OF WESTON AND TODD (1988 HIGH RESOLUTION DATA) WERE
NORMALIZED TO THE ENDF/B-VI STANDARD IN THE ENERGY RANGE FROM 1
KEV TO 2 KEV.
THE CROSS SECTIONS,CALCULATED FROM THE RESONANCE PARAMETERS
AND AVERAGED OVER 0.1 KEV INTERVALS,ARE GIVEN IN THE FOLLOWING
TABLE:
**************************************************************
CR0SS-SECTIONS(BARN)
------------------------------------------
TOTAL FISSION CAPTURE
ENERGY -------------- -------------- -------
(KEV) CALC(A) EXP(B) CALC(A) EXP(C) CALC(A)
**************************************************************
2.0-2.1 17.34 17.30 2.034 2.062 3.223
2.1-2.2 20.27 19.80 2.949 2.999 4.051
2.2-2.3 19.34 19.10 2.357 2.393 3.324
2.3-2.4 21.28 21.20 3.646 3.679 3.640
2.4-2.5 20.03 20.60 3.956 4.024 3.128
**************************************************************
2.0-2.5 19.65 19.60 2.989 3.031 3.473
**************************************************************
(A) TOTAL, FISSION AND CAPTURE CROSS SECTIONS CALCULATED BY
RESENDD, 1% ACCURACY, AT 300 K,FROM THE RESONANCE PARAME-
TERS.
(B) AVERAGE TOTAL CROSS SECTIONS OBTAINED FROM THE AVERAGE
EXPERIMENTAL EFFECTIVE CROSS SECTIONS IN REFERENCE/19/.
(C) 1988 HIGH RESOLUTION DATA OF WESTON AND TODD NORMALIZED
TO ENDF/B-VI STANDARD IN THE ENERGY RANGE FROM 1 KEV TO
2 KEV.
*****************************************************************
*****************************************************************
FISSION AND CAPTURE RESONANCE INTEGRALS
*****************************************************************
THE FISSION AND CAPTURE RESONANCE INTEGRALS ARE COMPARED TO
JENDL-3 DATA IN THE FOLLOWING TABLE:
**********************************************************
ENERGY RANGE(EV) FISSION(BARN) CAPTURE(BARN)
**********************************************************
JENDL-3 PRESENT JENDL-3 PRESENT
0.5 - 5.0 85.725 84.879 28.651 28.723
5.0 - 10.0 25.081 25.147 19.059 18.950
10.0 - 50.0 96.856 99.715 77.181 74.686
50.0 - 100.0 40.479 41.552 25.930 25.376
100.0 - 301.0 19.677 20.252 17.952 17.729
301.0 -1000.0 10.047 10.317 8.348 8.418
1000.0 -2000.0 3.484 3.206 2.840 2.634
2000.0 -2.E+07 17.783 (17.783) 5.224 (5.224)
**********************************************************
TOTAL 299.132 302.851 185.185 181.739
**********************************************************
THE JENDL-3 RESONANCE PARAMETERS ARE THOSE OBTAINED IN 1987 IN
THE ENERGY RANGE 0 KEV TO 1 KEV. THEY ARE SLIGTHLY DIFFERENT FROM
THOSE PUBLISHED IN 1989. THAT EXPLAINS THE SMALL DIFFERENCES OB-
SERVED BETWEEN JENDL-3 AND THE PRESENT RESULTS IN THIS ENERGY RAN-
GE. IN THE ENERGY RANGE 1 KEV TO 2 KEV JENDL-3 IS UNRESOLVED
RANGE. THE FISSION AND CAPTURE RESONANCE INTEGRALS CALCULATED
FROM ENDF/B-V AND THOSE FOUND IN BNL-325 ARE THE FOLLOWING:
ENDF/B-V FISSION: 302.13 B CAPTURE: 194.10 B
BNL-325 FISSION: 310+-10 B CAPTURE: 200+-20 B
THE CONSEQUENCE OF CHANGING FROM THE OLD SETS OF RESONANCE
PARAMETERS(ENDF/B-V AND PREVIOUS SETS) TO THE NEW SET IS THAT
THE CAPTURE RESONANCE INTEGRAL WILL DECREASE BY 6.7% COMPARED
WITH ENDF/B-V VALUE.
REFERENCES OF APPENDIX
1) R.GWIN ET AL.,NUCL.SCI.ENG.,45,25(1971)
2) R.GWIN ET AL.,NUCL.SCI.ENG.,59,79(1976)
3) R.GWIN ET AL.,NUCL.SCI.ENG.,61,116(1976)
4) R.GWIN ET AL.,NUCL.SCI.ENG.,88,37(1984)
5) J.BLONS, NUCL.SCI.ENG.,51,130(1973)
6) L.W.WESTON ET AL.,NUCL.SCI.ENG.88,567(1984)
7) L.W.WESTON ET AL.,TO BE PUBLISHED(HIGH RESOLUTION 1988 DATA)
8) R.R.SPENCER ET AL.,NUCL.SCI.ENG.,96,318(1987)
9) J.A.HARVEY ,MITO 1988,PAGE 115
10) A.CARLSON ET AL.,PRELIMINARY RESULTS OF THE ENDF/B-6 STANDARD
EVALUATION(SEPT 8 1987)
11) H.DERRIEN AND G. DE SAUSSURE,ORNL-TM-10986(1988)
12) H.DERRIEN ET AL.,NUCL.SCI.ENG.,106,434(1990)
13) H.DERRIEN, J.NUCL>SCI.TECHNOL.,30,845(1993).
14) N.M.LARSON ET AL.,ORNL/TM-7485,ORNL/TM-9179,ORNL/TM-9719/R1
15) L.LEAL AND R.N.HWANG,TRANS.AM.NUC.SOC.,55,340(1987)
16) T.NAKAGAWA,RESENDD A JAERI VERSION OF RESEND,JAER=-M 84-192
(1984).
17) C.WAGEMANS ET AL.,MITO 1988,PAGE 91
18) L.W.WESTON,PRIVATE COMMUNICATION(1992)
19) H.DERRIEN,J.NUCL.SCI.TECHNOL.,29,794(1992).