Abstract
Excited nuclear fragments are emitted during nuclear fission. The de-excitation of these fission fragments takes place as sequential emission of neutrons followed by photons. Correlations between neutron and photon multiplicities accompanying fission is thus expected. Fission event generators based on established statistical nuclear physics models predict negative event-by-event correlations in neutron–photon multiplicity. A survey of published experimental results of an event-by-event covariance between the neutron and photon multiplicities emitted following the spontaneous fission of 252Cf is presented. Analytic unfolding expressions are developed in this work to determine the bias introduced by background sources, particle misclassification, pulse pileup, and inelastic photon production. The published experimental data are re-analyzed using these unfolding techniques and are found to be in qualitative agreement with the predictions of model-based calculations. In particular, we have concluded that there exists a significant event-by-event neutron–photon emission competition following the spontaneous fission of 252Cf.
| Original language | English |
|---|---|
| Article number | 163907 |
| Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
| Volume | 968 |
| DOIs | |
| State | Published - Jul 11 2020 |
Funding
S. M. would like to thank Prof. P. Glässel and Dr. R. Schmid-Fabian for providing a copy of the dissertation published by the latter in 1987. S. M. is thankful to Prof. P. Glässel and Dr. D. Bleuel for discussions of their experimental results. S.M. would also like to acknowledge the contributions from Isabel E. Hernandez, Eoin P. Sansevero, and Dr. Tony H. Shin to the analysis of the experimental data, and Dr. Jørgen Randrup for discussion of the physical implications of our results in FREYA . This work was in part supported by the Office of Defense Nuclear Nonproliferation Research & Development (DNN R&D) , National Nuclear Security Administration , US Department of Energy . This research was funded in-part by the Consortium for Verification Technology under Department of Energy National Nuclear Security Administration award DE-NA0002534 . The work of V.A.P. was performed under the auspices of UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy . The work of R.V. was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344 . The work of P.T. and M.J.M. was performed under the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory under Contract DE-AC52-06NA25396 . S. M. would like to thank Prof. P. Gl?ssel and Dr. R. Schmid-Fabian for providing a copy of the dissertation published by the latter in 1987. S. M. is thankful to Prof. P. Gl?ssel and Dr. D. Bleuel for discussions of their experimental results. S.M. would also like to acknowledge the contributions from Isabel E. Hernandez, Eoin P. Sansevero, and Dr. Tony H. Shin to the analysis of the experimental data, and Dr. J?rgen Randrup for discussion of the physical implications of our results in FREYA. This work was in part supported by the Office of Defense Nuclear Nonproliferation Research & Development (DNN R&D), National Nuclear Security Administration, US Department of Energy. This research was funded in-part by the Consortium for Verification Technology under Department of Energy National Nuclear Security Administration awardDE-NA0002534. The work of V.A.P. was performed under the auspices of UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The work of R.V. was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The work of P.T. and M.J.M. was performed under the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory under Contract DE-AC52-06NA25396.
| Funders | Funder number |
|---|---|
| DNN R&D | |
| Office of Defense Nuclear Nonproliferation Research & Development | |
| US Department of Energy | |
| U.S. Department of Energy | |
| National Nuclear Security Administration | DE-AC05-00OR22725, DE-NA0002534 |
| Office of Defense Nuclear Nonproliferation | |
| Lawrence Livermore National Laboratory | DE-AC52-07NA27344 |
| Los Alamos National Laboratory | DE-AC52-06NA25396 |
Keywords
- Fission
- Fission fragment de-excitation
- Neutron–photon multiplicity competition