Direct Fast-Neutron Detection

Technical Report · Thu Dec 30 04:00:00 EST 1999

DOI:https://doi.org/10.2172/15001486· OSTI ID:15001486

Stromswold, David C; Peurrung, Anthony J; Hansen, Randy R; Reeder, Paul L

Direct fast-neutron detection is the detection of fast neutrons before they are moderated to thermal energy. We have investigated two approaches for using proton-recoil in plastic scintillators to detect fast neutrons and distinguish them from gamma-ray interactions. Both approaches use the difference in travel speed between neutrons and gamma rays as the basis for separating the types of events. In the first method, we examined the pulses generated during scattering in a plastic scintillator to see if they provide a means for distinguishing fast-neutron events from gamma-ray events. The slower speed of neutrons compared to gamma rays results in the production of broader pulses when neutrons scatter several times within a plastic scintillator. In contrast, gamma-ray interactions should produce narrow pulses, even if multiple scattering takes place, because the time between successive scattering is small. Experiments using a fast scintillator confirmed the presence of broader pulses from neutrons than from gamma rays. However, the difference in pulse widths between neutrons and gamma rays using the best commercially available scintillators was not sufficiently large to provide a practical means for distinguishing fast neutrons and gamma rays on a pulse-by-pulse basis. A faster scintillator is needed, and that scintillator might become available in the future. Results of the pulse-width studies were presented in a previous report (Peurrung et al. 1998), and they are only summarized here.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15001486
• Report Number(s): PNNL-13068; NN2001000
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
DETECTION
FAST NEUTRONS
MULTIPLE SCATTERING
NEUTRONS
PHOSPHORS
PLASTIC SCINTILLATORS
PRODUCTION
SCATTERING
VELOCITY