GEFY | Based fission-fragment Yield library in ENDF-format

Here you can download GEF-based fission-fragment yields 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 version 2023/3.2**

#### TABLES OF INDEPENDENT AND CUMULATIVE FISSION-FRAGMENT YIELDS FOR DOWNLOAD :

Spontaneous fission for isotopes from 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).

_{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}

See below the table with isomeric states.

* The tables that were given here before were calculated with only part of the isomers of JEFF-3.3 taken into account by a technial problem. The new tables are still incomplete.

See below the table with isomeric states.

**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 variation 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 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 from 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).

_{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}

See below the table with isomeric states.

* The tables that were given here before were calculated with only part of the isomers of JEFF-3.3 taken into account by a technial problem. The new tables are still incomplete.

See below the table with isomeric states.

**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 variation 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.

#### TABLES OF INDEPENDENT AND CUMULATIVE FISSION-FRAGMENT YIELDS FOR DOWNLOAD :

Spontaneous fission for isotopes from 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)

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

See below the table with isomeric states.

*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) | Spin/parity | 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+ | about 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 |