Prompt Fission Neutrons and γ Rays

Experiments to perform precision spectroscopy of fast neutron induced fission were carried out during the ν-Ball experimental campaign at the ALTO facility of IJC Laboratory Orsay. Low energy fission of 232Th(n,f), 238U(n,f) and spontaneous fission of 252Cf were studied using this hybrid highresolution spectrometer and calorimeter. New observables such as γ-ray multiplicity distributions correlated with specific fission fragments are presented and discussed. A new method using fast-timing techniques to detect prompt fission neutrons in coincidence with prompt fission γ-rays is described.

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Comprehensive modeling of prompt fission neutrons and γ rays in the spontaneous fission of 252Cf

EPJ Web of Conferences ◽

10.1051/epjconf/201714604031 ◽

2017 ◽

Vol 146 ◽

pp. 04031 ◽

Cited By ~ 1

Author(s):

Patrick Talou ◽

Ionel Stetcu ◽

Toshihiko Kawano

Keyword(s):

Spontaneous Fission ◽

Γ Rays ◽

Fission Neutrons ◽

Comprehensive Modeling ◽

Prompt Fission

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Multiplicity of scision neutrons from density functional scission dynamics

EPJ Web of Conferences ◽

10.1051/epjconf/202125600004 ◽

2021 ◽

Vol 256 ◽

pp. 00004

Author(s):

Nicolae Carjan ◽

Ionel Stetcu ◽

Margarit Rizea ◽

Aurel Bulgac

Keyword(s):

Density Functional ◽

Local Density ◽

Deformation Energy ◽

Energy Density Functional ◽

Functional Theory ◽

The Density Functional Theory ◽

Γ Rays ◽

Fission Neutrons ◽

Prompt Fission ◽

Neck Radius

The time evolution of the nuclear density of the fissioning system 240Pu during the scission process is obtained from the time-dependent superfluid local-density approximation (TDSLDA) to the density functional theory. A nuclear energy density functional based on the Skyrme force Skm* is used. The duration of the scission process Δt as well as the neck radius (rmin) of the ‘just-before scission’ configuration and the minimum separation (dmin) of the inner surfaces of the fragments in the ’immediately-after scission’ configuration were extracted in order to calculate the multiplicity of the scission neutrons (Vsc) using a phenomenological dynamical scission model (DSM). We find that Vsc=1.347, i.e. half of the prompt fission neutrons measured in the reaction 239Pu(nth; f) are released at scission. After scission, the fragments are left excited and with some extra deformation energy (mainly the heavy one). In this way we can account for the evaporation of the other half and for the emission of γ rays.

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The Fine Structure of Irradiated Mouse Heart

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090907 ◽

1976 ◽

Vol 34 ◽

pp. 184-185

Author(s):

Vivian V. Yang ◽

S. Phyllis Stearner

Keyword(s):

Microscopic Level ◽

Ultrastructural Changes ◽

Mouse Heart ◽

Blood Vessel Wall ◽

Histopathological Changes ◽

Light Microscopic Level ◽

Γ Rays ◽

Fission Neutrons ◽

Total Body

The heart is generally considered a radioresistant organ, and has received relatively little study after total-body irradiation with doses below the acutely lethal range. Some late damage in the irradiated heart has been described at the light microscopic level. However, since the dimensions of many important structures of the blood vessel wall are submicroscopic, investigators have turned to the electron microscope for adequate visualization of histopathological changes. Our studies are designed to evaluate ultrastructural changes in the mouse heart, particularly in the capillaries and muscle fibers, for 18 months after total-body exposure, and to compare the effects of 240 rad fission neutrons and 788 rad 60Co γ-rays.Three animals from each irradiated group and three control mice were sacrificed by ether inhalation at 4 days, and at 1, 3, 6, 12, and 18 months after irradiation. The thorax was opened and the heart was fixed briefly in situwith Karnofsky's fixative.

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Average cross sections for the interaction of nuclides with prompt fission neutrons

Soviet Atomic Energy ◽

10.1007/bf01121127 ◽

1981 ◽

Vol 50 (4) ◽

pp. 271-272

Author(s):

B. I. Starostov ◽

L. N. Kudryashov

Keyword(s):

Cross Sections ◽

Fission Neutrons ◽

Prompt Fission

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Measurement of energy spectrum and average number of prompt fission neutrons

Soviet Atomic Energy ◽

10.1007/bf01159591 ◽

1970 ◽

Vol 29 (2) ◽

pp. 790-793 ◽

Cited By ~ 8

Author(s):

N. I. Kroshkin ◽

Yu. S. Zamyatnin

Keyword(s):

Energy Spectrum ◽

Fission Neutrons ◽

Prompt Fission

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Uncertainty Quantification on Prompt Fission Neutrons Spectra

Nuclear Data Sheets ◽

10.1016/j.nds.2008.11.023 ◽

2008 ◽

Vol 109 (12) ◽

pp. 2858-2862 ◽

Cited By ~ 5

Author(s):

P. Talou ◽

D.G. Madland ◽

T. Kawano

Keyword(s):

Uncertainty Quantification ◽

Fission Neutrons ◽

Prompt Fission

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Detection of Combined n/γ Fission Signatures Induced by an Epithermal Neutron Source

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4036698 ◽

2017 ◽

Vol 3 (3) ◽

Author(s):

A. Ocherashvili ◽

T. Bogucarska ◽

A. Beck ◽

G. Heger ◽

M. Mosconi ◽

...

Keyword(s):

Neutron Source ◽

Proper Time ◽

Pulse Shape Discrimination ◽

Fast Neutrons ◽

Nuclear Materials ◽

Test Assembly ◽

Fission Neutrons ◽

Pulsed Neutron ◽

Prompt Fission ◽

Multiple Detectors

In this paper, a method is presented for the detection of special nuclear materials (SNMs) in shielded containers, which is both sensitive and applicable under field conditions. The method uses an external pulsed neutron source to induce fission in SNM and subsequent detection of the fast prompt fission neutrons. The detectors surrounding the container under investigation are liquid scintillation detectors able to distinguish gamma rays from fast neutrons by means of pulse shape discrimination method (PSD). One advantage of these detectors, besides the ability for PSD analysis, is that the analog signal from a detection event is of very short duration (typically few tens of nanoseconds). This allows the use of very short coincidence gates for the detection of the prompt fission neutrons in multiple detectors, while benefiting from a low background coincidence rate, yielding a low detection limit. Another principle advantage of this method derives from the fact that the external neutron source is pulsed. By proper time gating, the interrogation can be conducted by epithermal source neutrons only. These neutrons do not appear in the fast neutron signal following the PSD analysis, thus providing a fundamental method for separating the interrogating source neutrons from the sample response in the form of fast fission neutrons. This paper describes laboratory tests with a configuration of eight detectors in the Pulsed Neutron Interrogation Test Assembly (PUNITA). Both the photon and neutron signature for induced fission is observed, and the methods used to isolate these signatures are described and demonstrated.

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