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The measurement of the energy correlations between two 252Cf prompt fission neutrons

01.31.26 | Nuclear Science and Techniques

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The experimental setup photograph.
In the experiment, 8 CLYC detectors, positioned 6 cm away from the252Cf neutron source, are utilized to detect the prompt fissionγ-rays, and 16 EJ309 liquid scintillation detectors, positioned 60 cm away from the252Cf neutron source, are used to detect the neutrons andγ-rays at 0°, 90°, 180° and 270°. Credit: Huai-Yong Bai

Investigating the Energy Correlation of Prompt Fission Neutrons

The energy correlations of prompt fission neutrons have typically been overlooked in neutron coincidence and multiplication measurement techniques, despite these methods being widely applied and even adopted as standards in various fields. This omission may introduce measurement deviations, particularly because detection efficiency is energy-dependent. This is especially critical for fast neutron coincidence and multiplication measurement techniques.

Time-Correlation Measurement Techniques
Several measurement techniques are employed to reliably obtain the experimental energy correlations of prompt fission neutrons. These including the prompt fission γ-ray tagging technique, pulse shape discrimination (PSD), time-of-flight (TOF) measurement, and time-correlation analysis method.

Contributing to the Development of Fission Physics
Energy spectra of prompt fission neutrons from 252 Cf were obtained，correlated with neutrons of different energies. The measurements reveal that energy correlation between the coincident neutrons at 180° is positive, whereas the correlation at 90° is negative. These data are invaluable for the development and verification of fission physics theories.

Implications for Neutron Coincidence and Multiplication Measurement Techniques
The study confirms that the energies of prompt fission neutrons are interrelated. This finding indicates that the neutron energy correlations should be considered in the coincidence and multiplication measurement techniques to ensure more reliable measurement results, particularly for the fast neutron coincidence and multiplication measurement techniques.

The complete study is via by DOI: https://doi.org/10.1007/s41365-025-01881-3

Nuclear Science and Techniques

10.1007/s41365-025-01881-3

Computational simulation/modeling

Not applicable

The measurement of the energy correlations between two 252Cf prompt fission neutrons

29-Jan-2026

Additional Media

Simulated neutron energy correlations at 0° (a), 30° (b), 60° (c), 90° (d), 120° (e), 150° (f) and 180° (g).
The simulated neutron energy correlations vary with angle. For the correlated events at near 90°, the energy of the second neutron tends toward lower values, whereas for the correlated events at near 0° or 180°, it tends toward higher values. These trends become more pronounced as the energy of the first neutron increases. Credit: Huai-Yong Bai
Measured neutron coincident events at 90° (a) and 180° (b).
There are 5 types of interfering events in the measured neutron coincidence events at 90° and 180°. The first type, shown in the purple box, corresponds toγ-ray events; the second type, shown in the green box, refers to cases where the first neutron is an accidental coincidence neutron; the third type, shown in the red box, refers to cases where the second neutron is an accidental coincidence neutron; the fourth type, shown in the black frame, refers to cases where theγ-ray is an accidental coin Credit: Huai-Yong Bai
Measured relative ratios of the measured energy spectra correlated with different energy neutrons at 90° (a) and 180° (b) to the 252Cf prompt fission neutron energy spectrum.
The measurement results indicate that the influence of a neutron on the energy of the correlated neutron is more pronounced in the high energy region, and the related effect at 180° appears to be more noticeable than that at 90°. In addition to the difference in effect magnitude, the energy of the correlated neutron exhibits opposite trends between the correlated events at 90° and those at 180°. With the measured relative ratios, the related neutron energy spectra can be derived by multiplying t Credit: Huai-Yong Bai
The PH-PSD two dimensional spectra of a CLYC detector (a) and an EJ309 liquid scintillation detector (b).
The PSD performance of the 8 CLYC detectors and the 16 liquid scintillation detectors used in the experiment was excellent. By applying optimal discrimination thresholds, the event types (γ-ray or neutron) could be accurately identified. Credit: Huai-Yong Bai

Keywords

Nuclear Reactions Particle Physics

Article Information

Journal
Nuclear Science and Techniques
DOI
10.1007/s41365-025-01881-3
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Publication Date
2026-01-29
Article Title
The measurement of the energy correlations between two 252Cf prompt fission neutrons

Contact Information

Lihua Sun
Nuclear Science and Techniques
nst@sinap.ac.cn

Source

Original Source
https://link.springer.com/article/10.1007/s41365-025-01881-3

How to Cite This Article

APA:
Nuclear Science and Techniques. (2026, January 31). The measurement of the energy correlations between two 252Cf prompt fission neutrons. Brightsurf News. https://www.brightsurf.com/news/L7V0Q5O8/the-measurement-of-the-energy-correlations-between-two-252cf-prompt-fission-neutrons.html
MLA:
"The measurement of the energy correlations between two 252Cf prompt fission neutrons." Brightsurf News, Jan. 31 2026, https://www.brightsurf.com/news/L7V0Q5O8/the-measurement-of-the-energy-correlations-between-two-252cf-prompt-fission-neutrons.html.