GEFY
GEF-based
fission-fragment yield library in ENDF format
GEFY 9.1
(December 2023):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Isomeric independent yields and cumulative yields
were calculated using the decay data of JEFF 3.3.
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF
code, version 2023/3.2.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106 (Calculation
with 10^6 events per system).
- Neutron-induced fission of target nuclei of Z 86 to Z = 98
(En=thermal to En=30 MeV in 59 steps). (Calculation
with 10^6 events per system).
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system).
GEFY 8.1
(July 2020):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Isomeric independent yields and cumulative yields
were calculated using the decay data of JEFF 3.3.
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF
code, version 2020/1.1.
Correction of interpolation scheme applied in January 2021.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106 (Calculation
with 10^6 events per system).
- Neutron-induced fission of target nuclei of Z 86 to Z = 98
(En=thermal to En=30 MeV in 59 steps). (Calculation
with 10^6 events per system).
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system).
Table of isomeric states see below.
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
- Neutron-induced fission (En up to 20 MeV in 77 steps) of
235U,
238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am with 10^6 events per
system. (Not yet available.)
Energy steps in MeV: 0.1E-10, 0.0253E-6, 1.E-7, 5.E-7, 1.E-6, 5.E-6,
1.E-5, 5.E-5, 1.E-4, 5.E-4, 1.E-3, 5.E-3, 1.E-2, 2.E-2, 3.E-2, 4.E-2,
5.E-2, 6.E-2, 7.E-2, 8.E-2, 9.E-2, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3,
3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11,
11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,
18.5, 19, 19.5, 20
GEFY 7.2
(September 2019):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Cumulative yields
were calculated using the decay data of JEFF 3.1.1.
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF
code, version 2019/1.2.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106 (Calculation
with 10^6 events per system) .
- Neutron-induced fission of target nuclei of Z 86 to Z = 98
(En=thermal to En=30 MeV in 59 steps). (Calculation
with 10^6 events per system).
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system).
Table of isomeric states see below.
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
- Neutron-induced fission (En up to 20 MeV in 77 steps) of
235U,
238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am with 10^6 events per
system. (Not yet available.)
Energy steps in MeV: 0.1E-10, 0.0253E-6, 1.E-7, 5.E-7, 1.E-6, 5.E-6,
1.E-5, 5.E-5, 1.E-4, 5.E-4, 1.E-3, 5.E-3, 1.E-2, 2.E-2, 3.E-2, 4.E-2,
5.E-2, 6.E-2, 7.E-2, 8.E-2, 9.E-2, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3,
3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11,
11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,
18.5, 19, 19.5, 20
GEFY 7.1
(February 2019):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Cumulative yields
were calculated using the decay data of JEFF 3.1.1.
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF
code, version 2019/1.1.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106 (Calculation
with 10^6 events per system) .
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system)
Table of isomeric states see below.
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
- Neutron-induced fission (En up to 20 MeV in 77 steps) of 235U,
238U,
238Pu,
239Pu,
240Pu,
241Pu,
242Pu,
and 241Am
with 10^6 events per system.
Energy steps in MeV: 0.1E-10, 0.0253E-6, 1.E-7, 5.E-7, 1.E-6, 5.E-6,
1.E-5, 5.E-5, 1.E-4, 5.E-4, 1.E-3, 5.E-3, 1.E-2, 2.E-2, 3.E-2, 4.E-2,
5.E-2, 6.E-2, 7.E-2, 8.E-2, 9.E-2, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3,
3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11,
11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18,
18.5, 19, 19.5, 20
GEFY 6.2
(June 2018):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Cumulative yields
were calculated using the decay data of JEFF 3.1.1 with some extensions
from ENSDF (Nuclear Wallet Cards database version of 6/1/2012).
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF
code, version 2018/1.1.
Comparisons of calculated fission-fragment yields with evaluations and
other data are shown in this
gallery.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106.
(Calculation
with 10^6 events per system, produced with version
GEF-2018/1.1.)
- Neutron-induced fission (En=thermal to En=30 MeV in 59 steps) for
isotopes of Z = 86 to Z = 98.
(Calculation
with 10^6 events per system, produced with version
GEF-2018/1.1.)
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system, produced with version
GEF-2018/1.1.)
Table of isomeric states see below.
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
GEFY 6.1
(November 2016):
Independent and cumulative
fission-fragment yields.
Multi-chance fission
is considered.
Uncertainties
reflect the uncertainties of the model. They are determined from
calculations with perturbed model parameters.
For this purpose, a series of calculations was performed with different
sets of model parameters. Each parameter in these sets was varied
randomly with a standard deviation corresponding to the uncertainty of
the respective parameter deduced from the fit to experimental fission
data.
Cumulative yields
were calculated using the decay data of JEFF 3.1.1 with some extensions
from ENSDF (Nuclear Wallet Cards database version of 6/1/2012).
Nuclides with half-lives longer than 1.E6 years were
treated as
stable. Very neutron-rich fragments, for which no experimental decay
information is available, were assumed to decay by beta-minus decay
only.
The calculations have
been performed with the GEF code, version 2016/1.1 or version 2016/1.2
(see notice below).
Notice:
We observed that GEF-2016/V1.1 overestimates the fragment excitation
energies for incoming neutron energies above 10 MeV. New GEFY tables
with the corrected version GEF-2016/V1.2 are successively provided. The
random files are already calculated with GEF-2016/V1.2.
Tables of independent and
cumulative fission-fragment yields for download:
- Spontaneous fission for isotopes of Z = 89 to Z = 106.
(Calculation
with 10^8 events per system, produced with version
GEF-2016/1.1.)
- Neutron-induced fission (En=thermal to En=30 MeV in 59 steps) for
isotopes of Z = 86 to Z = 98.
(Calculation
with 10^6 events per system, produced with version
GEF-2016/1.2.)
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
- Neutron-induced fission (En=10^-11 to 20 MeV in 77 steps) for
235,238U, 238-242Pu, 241Am.
(Calculation
with 10^8 events per system, produced with version
GEF-2016/1.2.)
Energy
steps in MeV: 0.1E-10,
0.0253E-6, 1.E-7, 5.E-7, 1.E-6, 5.E-6, 1.E-5, 5.E-5, 1.E-4, 5.E-4,
1.E-3, 5.E-3, 1.E-2, 2.E-2, 3.E-2, 4.E-2, 5.E-2, 6.E-2, 7.E-2, 8.E-2,
9.E-2, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3,
1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5,
7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14,
14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, 20
- Neutron-induced fission of target nuclei in isomeric states
(half-life > 1 s). (En=thermal to En=30 MeV in 59 steps).
(Calculation
with 10^6 events per system, produced with version
GEF-2016/1.1.)
Table of isomeric states see below.
Energy steps in MeV: 0.0253E-6,
0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12,
12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19,
19.5, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
Random files of
independent and cumulative fission-fragment yields:
For a limited number of systems, a series of random
files is provided on the MagentaCLOUD.
These random files provide fission-fragment yields
in ENDF format with an
indirect numerical presentation of variances and covariances according
to the GEF model. For each system and each energy, a series of
500 calculations was performed with perturbed parameters. The
parameters of
each of these calculations were chosen independently within the
uncertainty range of the GEF model.
The
tables are intended for model calculations based on fission yields in
ENDF format. By performing these calculations with the different random
files for the same system and the same incoming-neutron energy, the
uncertainties and the covariances of the yields according to the GEF
model are included in the calculation. This procedure has several
advantages. For example, no special format for the covariances is
required and the production of random fission-yield data on the basis
of
the covariances is not needed. Moreover, the restriction by the
functional form of the multivariate distribution is not an issue.
List of the energy steps:
| Step |
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
11
|
12
|
13
|
14
|
15
|
16
|
17
|
18
|
19
|
| Energy / MeV |
thermal |
0.1
|
0.2
|
0.3
|
0.4
|
0.5
|
0.6
|
0.7
|
0.8
|
0.9
|
1.0
|
1.5
|
2.0
|
2.5
|
3.0
|
3.5
|
4.0
|
4.5
|
5.0
|
The calculations of the
random files were performed with the GEF code, version 2016/1.2.
Explanation of the file names:
GEFY_92_235_n_Ei_Rj.rnd contains the calculated yields for
neutron-induced fission from a 235U target, incident-neutron energy
step number "i" and perturbed-parameter set "j". (Note that all
perturbed parameter sets are different. They are all chosen
independently at random. Also those with the same number but for
different targets are not the same.)
The
files of GEFY 5.2 (September 2015) and GEFY 5.3 (March 2016) are not
available any more.
Isomeric
states from ENSDF (Nuclear Wallet Cards database version of 6/1/2012)
are listed in the table below. Values that are not known were replaced
by zero.
| Nuclide |
E(isomer) |
Jπ |
Half-life (ENSDF)
|
File name |
| 222Ac |
> 0 keV |
? |
63 s |
GEFY_89_222m1_n.dat |
| 229Th |
100 eV |
(3/2+) |
2 min ? |
GEFY_90_229m1_n.dat |
| 234Pa |
73.9 keV
|
(0-) |
1.159 min |
GEFY_91_234m1_n.dat |
| 235U |
0.1 keV |
1/2+ |
≈ 26 min |
GEFY_92_235m1_n.dat |
| 236Np |
> 0 keV |
1 |
22.5 h |
GEFY_93_236m1_n.dat |
| 240Np |
> 0 keV
|
(1+) |
7.22 min |
GEFY_93_240m1_n.dat |
| 242Np |
> 0 keV |
(6+) |
5.5 min |
GEFY_93_242m1_n.dat |
| 242Am |
48.6 keV |
5- |
141 y |
GEFY_95_242m1_n.dat |
| 244Am |
86.1 keV |
1+ |
26 min |
GEFY_95_244m1_n.dat |
| 246Am |
> 0 keV |
2(-) |
25.0 min |
GEFY_95_246m1_n.dat |
| 248Bk |
> 0 keV |
1(-) |
23.7 h |
GEFY_97_248m1_n.dat |
| 250Es |
> 0 keV |
1(-) |
2.22 h |
GEFY_99_250m1_n.dat |
| 254Es |
83.7 keV |
2+ |
39.3 h |
GEFY_99_254m1_n.dat |
| 256Es |
> 0 keV |
(8+) |
7.6 h |
GEFY_99_256m1_n.dat |
| 250Fm |
> 0 keV
|
? ? |
1.93 s |
GEFY_100_250m1_n.dat |
Comments and suggestions are welcome. Please address these to
schmidt-erzhausen (at) t-online.de .