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IAEA CRP on a Reference Database for Beta-Delayed Neutron Emission
Code F41028; Duration 2013-2018
CRP completed - final database and publications
Tables of compiled and evaluated half-lives and beta-delayed neutron emission probabilities for individual precursors:
The final CRP technical report on compiled, evaluated and validated microscopic and macroscopic delayed-neutron data:
The database containing all the microscopic and macroscopic delayed-neutron data:
Consultant's Meeting on Benchmarking the New Evaluated beta-delayed neutron data
Participants of the CRP who are involved in measurements, compilations and calculations of macroscopic delayed neutron data such as total delayed neutron yields,
average half-lives and delayed-neutron spectra, attended a Consultant' Meeting from 13 to 15 December 2017 at the IAEA, to discuss the impact of the newly evaluated beta-delayed neutron emission probabilities
produced by the CRP evaluators on these macrosocpic data, the new systematics of measured macrosocpic data and the contents of the final CRP document.
More information about the meeting is available here.
IAEA TM on Fission Product Yields: status and perspectives
The yields of fission products produced after the fission process and subsequent decay of fission fragments are important data for calculating the total yields and other aggregate properties of delayed neutrons such as decay rates, decay constants and delayed neutron spectra, using the summation method.
A meeting was held at the IAEA, Vienna, from 23 to 26 May 2016, to assess the current status of fission product yields in terms of a) measurements, b) modelling and evaluation, and c) evaluation of covariances. The presentations, participants list and summary report are available here.
Theoretical calculations of β-decay properties
β-decay half-lives and β-delayed neutron emission probabilities, including first-forbidden transitions, have been calculated within a fully self-consistent microscopic theoretical framework.
The results were used in an r-process nucleosynthesis calculation to assess the sensitivity of heavy element nucleosynthesis to weak interaction reaction rates. By Marketin et al., in Phys. Rev. C 93, 025805 (2016). A supplemental table with all the calculated properties is also available here.
Evaluation of beta-delayed neutron emission probabilities Pn and T1/2 for Z = 2-28
The compilation and evaluation of beta-delayed neutron emission probabilities and half-lives for nuclides in the Z = 2-28 region performed within the CRP has been published by Birch et al., in Nuclear Data Sheets 128, 131 (2015). The article includes tables of compiled and evaluated data, as well as systematics.
Systematics of beta-delayed neutron emission probabilities
A phenomenological model of the beta-delayed neutron-emission probability, based on a level density function, was developed. The effective level density systematics, empirically determined from the experimental data, have been modeled and used to determine beta-delayed neutron-emission probabilities. The work was performed by K. Miernik and is now published in PRC 88, 041301(R) (2013) [PDF]. Files containing the calculated data and graphical presentations can be downloaded from this [link].
The CRP on beta-delayed neutron emission data
CRP Objective
The overall CRP Objective is to enhance Member States' (MS) knowledge and calculational capabilities in the fields of nuclear energy, safeguards, used fuel and
waste management and nuclear sciences by creating a Reference Database for Beta-Delayed Neutron Emission that contains both a
compilation of existing data, evaluated data and recommended data, which will be made readily available to the user community. The project starts in 2013 and will have a duration of 4 years.
Specific Research Objectives
- Compile the existing beta-delayed neutron data, in particular half-lives, neutron emission probabilities and neutron spectra for
individual precursors
- Produce a priority list for evaluations and new measurements
- Define and document the evaluation methodology and the "Standards" for delayed neutron emission of individual precursors in different mass regions
- Produce tools for predicting delayed-neutron properties for non-measured nuclei using of theoretical models or systematic trends
- Create a reference database of evaluated data related to the beta-delayed neutron emissioof RIKENn process
- Re-evaluate the beta-delayed neutron reaSee attached filector constants in appropriate group format for energy applications and produce the recommended database
Expected Research Outputs
- Reference Database of beta-delayed neutron emission properties
- Re-evaluated reactor delayed-neutron constants for fissile actinides
- Technical document describing the evaluation methodology and the new database
Useful material
Reviews New Data Compilation/Evaluation Systematics/Theory Neutron Spectra Macroscopic Data Summation Method Group Spectra
# | Date | Author | Title | Link | Documents on status of delayed neutron data | 1 | August 1979 | see doc | Proc. of Consultants Meeting on Delayed Neutron Properties (INDC(NDS)-107/G) | PDF | 2 | Sept. 1986 | Ed. D.R. Weaver | Delayed Neutron Properties, Proc. of the Specialists Meeting, Univ. of Birmingham | Link | 3 | December 1990 | see doc | Status of Delayed Neutron Data-1990 (NEA Data Bank/NEA CRP-L-323) | Link | 4 | July 1999 | see doc | Proc. of the Specialist's Meeting on Delayed Neutron Nuclear Data (INDC(JPN)-0184) | PDF | 5 | July 2002 | A. D'Angelo | Overview of the delayed neutron data activities and results monitored by the NEA/WPEC subgroup 6 | Link | 6 | July 2002 | D'Angelo and Rowlands | Conclusions concerning the Delayed Neutron Data for the Major Actinides | Link |
# | Year | Author | Title | Link | New experimental data relevant for β-delayed neutron emission from Individual Precursors | 1 | 2013 | Mazzocchi et al | New half-life measurements of the most neutron-rich arsenic and germanium isotopes | Phys. Rev. C 87, 034315 | 2 | 2013 | Miernik et al | β-decay study of neutron-rich bromine and krypton isotopes | Phys. Rev. C 88, 014309 | 3 | 2013 | Miernik et al | Large β-Delayed One and Two Neutron Emission Rates in the Decay of 86Ga | Phys. Rev. Lett. 111, 132502 | 4 | 2013 | Korgul et al | Experimental study of the β-γ and β-n decay of the neutron-rich nucleus 85Ga | Phys. Rev. C 88, 044330 | 5 | 2014 | Miernik et al | Excited states in 82As studied in the decay of 82Ge | Phys. Rev. C 90, 034311 | 6 | 2014 | Korgul et al | Structure of Neutron Rich-Nuclei Beyond N = 50 | Acta Physica Polonica B 45, 223 | 7 | 2014 | Grzywacz et al | Hybrid-3Hen-New Detector for Gammas and Neutrons | Acta Physica Polonica B 45, 217 | 8 | 2014 | K. Rykaczewski | Decay Studies of 238U Fission Products at the HRIBF (Oak Ridge) | Nuclear Data Sheets 120, 16-21 | 9 | 2014 | A. Fijalkowska | First Results from the Modular Total Absorption Spectrometer at the HRIBF | Nuclear Data Sheets 120, 26-29 | 10 | 2014 | Miernik et al | No Evidence of Isomerism for the First Excited State of 93Rb | Nuclear Data Sheets 120, 56-58 | 11 | 2014 | Rajabali et al | β decay of 72Co and microsecond isomers in even-mass neutron-rich nickel isotopes | J. Phys. G: Nucl. Part. Phys. 41, 115104 | 12 | 2014 | Gomez-Hornillos et al | β-delayed neutron emission studies | Hyperfine Interactions, 223, 185-194 | 13 | 2014 | Algora et al | Total Absorption Study of Beta Decays Relevant for Nuclear Applications and Nuclear Structure | Nuclear Data Sheets, 120, 12-15 | 14 | 2014 | Agramunt et al | New Beta-delayed Neutron Measurements in the Light-mass Fission Group | Nuclear Data Sheets, 120, 74-77 | 15 | 2014 | Caballero-Folch et al | β-decay and β-delayed Neutron Emission Measurements at GSI-FRS Beyond N=126, for r-process Nucleosynthesis | Nuclear Data Sheets, 120, 81-83 | 16 | 2014 | Martinez et al | MONSTER: a TOF Spectrometer for β-delayed Neutron Spectroscopy | Nuclear Data Sheets, 120, 78-80 | 17 | 2015 | Tain et al | The sensitivity of LaBr3:Ce scintillation detectors to low energy neutrons: Measurement and Monte Carlo simulation | Nucl. Instrum. Methods A 774, 17-24 | 18 | 2015 | Liddick et al | Analogous intruder behavior near Ni, Sn, and Pb isotopes | Phys. Rev. C 92, 024319 | 19 | 2015 | Mazzocchi et al | β-decay properties of the very neutron-rich isotopes 86Ge and 86As | Phys. Rev. C 92, 054317 | 20 | 2015 | Korgul et al | Experimental study of β and β-n decay of the neutron-rich N = 54 isotone 87As | Phys. Rev. C 92, 054318 | 21 | 2016 | Agramunt et al | Characterization of a neutron-beta counting system with beta-delayed neutron emitters | Nucl. Instrum. Methods A 807, 69-78 | 22 | 2016 | Alshudifat et al | Reexamining Gamow-Teller decays near 78Ni | Phys. Rev. C 93, 044325 | 23 | 2016 | Korgul et al | β and β-n decay of the neutron-rich 84Ge nucleus | Phys. Rev. C 93, 064324 | 24 | 2016 | Caballero-Folch et al | First measurement of several beta-delayed neutron emitting isotopes beyond N=126 | Phys. Rev. Lett. 117, 012501 | 25 | 2016 | Miernik et al | β-decay study of 94Kr | Phys. Rev. C 94, 024305 | 26 | 2016 | Rasco et al | Decays of the Three Top Contributors to the Reactor νe High-Energy Spectrum, 92Rb, 96gsY, and 142Cs, Studied with Total Absorption Spectroscopy | Phys. Rev. Lett. 117, 092501 | 27 | 2016 | Madurga et al | Evidence for Gamow-Teller Decay of 78Ni Core from Beta-Delayed Neutron Emission Studies | Phys. Rev. Lett. 117, 092502 | 28 | 2017 | Wu et al | 94 β-Decay Half-Lives of Neutron-Rich 55Cs to 67Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation | Phys. Rev. Lett. 118, 072701 (2017) Supplemental Data Tables | 29 | 2017 | Korgul et al | Experimental study of the β decay of the very neutron-rich nucleus 85Ge | Phys. Rev. C 95, 044305 | 30 | 2017 | Tarifeno-Saldivia et al | Conceptual design of a hybrid neutron-gamma detector for study of β-delayed neutrons at the RIB facility of RIKEN | JINST 12 P04006 | 31 | 2017 | Rasco et al | Complete β-decay pattern for the high-priority decay-heat isotopes 137I and 137Xe determined using total absorption spectroscopy | Phys. Rev. C 95, 054328 |
Delayed Neutron Energy Spectra
# | Year | Author | Title | Link | 1 | 1976 | G. Rudstam | Characterization of Delayed Neutron Spectra (INDC-835/INDC(SWD)-9/G+P) | PDF | 2 | 1980 | Reeder et al | Energy Spectra of Delayed Neutrons from the Separated Precursors Rb-93, -94, -95 and Cs-143 | Nucl. Sci. Eng. 75, 1980, 140 | 3 | 1985 | Greenwood and Caffrey | Delayed-Neutron Energy Spectra of 93-97Rb and 143-145Cs | Nucl. Sci. Eng. 91, 1985, 305 | 4 | 1997 | Greenwood and Watts | Delayed neutron Energy Spectra of 87Br, 88Br, 89Br, 137I, 138I, and 136Te | Nucl. Sci. Eng. 126, 1997, 324 | 5 | 1989 | M. Brady | Evaluation and Application of Delayed Neutron Data | Thesis | 6 | 2015 | Piksaikin et al | High Resolution Measurements of Aggregate Delayed Neutron Spectra in Different Time Intervals from Thermal Neutron Induced Fission of 235U | INDC(NDS)-0689 | 7 | 2017 | Piksaikin et al | High resolution measurements of time-dependent integral delayed neutron spectra from thermal neutron induced fission of 235U | Ann. Nuclear Energy 102, 2017, 408 |
Integral Delayed Neutron Data
# | Year | Author | Title | Link | 1 | 1979 | Tuttle R.J. | Delayed Neutron Yield in Nuclear Fission | CM Report 1979 | 2 | 1999 | Spriggs and Campbell | A Summary of Measured Delayed Neutron Group Parameters | LANL report LA-UR-98-918 | 3 | 2002 | Piksaikin et al | Characteristics of Delayed Neutrons Systematics and Correlation Properties | Progress in Nuclear Energy 41, p. 361 | 4 | 2002 | Piksaikin et al | Energy dependence of relative abundances and periods of delayed neutrons from neutron-induced fission of 235U, 238U, 239Pu in 6- and 8-group model representation | Progress in Nuclear Energy 41, p. 203 | 5 | 2002 | Piksaikin et al | Experimental studies of the absolute total delayed neutron yields from neutron-induced fission of 238U in the energy range 1-5 MeV | Progress in Nuclear Energy 41, p. 135 | 6 | 2002 | Spriggs et al | An 8-group Neutron Model Based on Consistent set of Half-lives | Progress in Nuclear Energy 41, p. 223 | 7 | 2013 | Piksaikin et al | The absolute total delayed neutron yields, rel. abundances and half-lives of delayed neutron groups in 6- and 8-group model from neutron-induced fission of 232Th, 233U, 236U, 239Pu and 241Am in the energy range from 0.35 MeV to 5 MeV | INDC(NDS)-0646 | 8 | 2015 | Piksaikin et al | Verification of the evaluated fission product yields data from the neutron induced fission of 235U, 238U and 239Pu based on the delayed neutron characteristics | Progress in Nuclear Energy 83, p. 13 | 9 | 2017 | Egorov et al | Measurement of the delayed neutron characteristics in the interaction of relativistic protons with 238U nuclei | Progress in Nuclear Energy 97, p. 106 | 10 | 2017 | Piksaikin et al | High resolution measurements of time-dependent integral delayed neutron spectra from thermal neutron induced fission of 235U | Annals of Nuclear Energy 102, p. 408 |
Summation Method
# | Year | Author | Title | Link | 1 | 1982 | Rudstam | Six-Group Representation of the Energy Spectra of Delayed Neutrons from Fission | Nucl. Sci. Eng. 80, 238-255 (1982) | 2 | 1989 | Brady and England | Delayed Neutron Data and Group Parameters for 43 Fissioning Systems | Nucl. Sci. Eng. 103, 129-149 (1989) | 3 | 1991 | Mills et al | Study of the Delayed Neutron Yield and its Time Dependence by Summation Method, and the sensitivity of the Yield to Parameters of the Independent Yield Model and Decay Data | Proc. Int. Conf. Nucl. Data for Sci. Technology, Julich 1991, (Ed. Springer-Verlag, Berlin, 1991), p. 86-88 | 4 | 2002 | Wilson and England | Delayed Neutron Study Using ENDF/B-VI Basic Nuclear Data | Prog. Nuc. Energy 41, 71-107 (2002) | 5 | 2002 | Campbell and Spriggs | Delayed Neutron Spectral Data for Hansen-Roach Energy Group Structure | Prog. Nuc. Energy 41, 253-283(2002) |
Experimental Aggregate Delayed Neutron Spectra
# | Year | Author | Title | Link | 1 | 1974 | Sloan and Woodruff | Spectrum of Delayed Neutrons from the Thermal-Neutron Fission of 235U (EXFOR-10576002) | Nucl. Sci. Eng. 55, 28 (1974) | 2 | 1977 | Eccleston and Woodruff | Measured Near-Equilibrium Delayed Neutron Spectra Produced by Fast-Neutron-Induced Fission of 232Th, 233U, 235U, 238U, and 239Pu (EXFOR-10640004) | Nucl. Sci. Eng. 62, 636 (1977) | 3 | 1977 | Evans and Krick | Equilibrium Delayed Neutron Spectra from Fast Fission of U-235, U-238, and Pu-239 (EXFOR-10489002) | Nucl. Sci. Eng. 62, 654 (1977) | 4 | 1977 | Saphier et al | Evaluated Delayed Neutron Spectra and their Importance in Reactor Calculations (EXFOR-V001002-11) | Nucl. Sci. Eng. 62, 660 (1977) | 5 | 1986 | Tanczyn et al | Composite Delayed Neutron Energy Spectra for Thermal Fission of 235U (EXFOR-13800002) | Nucl. Sci. Eng. 94, 353 (1986) | 6 | 1988 | Sharfuddin et al | Search for an Energy Dependence in 235U Delayed Neutron Spectra (EXFOR-13799002) | Nucl. Sci. Eng. 98, 341 (1988) |
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