Conceptual design and initial evaluation of a neutron flux gradient detector
Journal article, 2022

Identification of the position of a localized neutron source, or that of local inhomogeneities in a multiplying or scattering medium (such as the presence of small, strong absorbers) is possible by measurement of the neutron flux in several spatial points, and applying an unfolding procedure. It was suggested earlier, and it was confirmed by both simulations and pilot measurements, that if, in addition to the usually measured scalar (angularly integrated) flux, the neutron current vector or its diffusion approximation (the flux gradient vector) is also considered, the efficiency and accuracy of the unfolding procedure is significantly enhanced. Therefore, in support of a recently started project, whose goal is to detect missing (replaced) fuel pins in a spent fuel assembly by non-intrusive methods, this idea is followed up. The development and use of a dedicated neutron detector for within-assembly measurements of the neutron scalar flux and its gradient are planned. The detector design is based on four small, fiber-mounted scintillation detector tips, arranged in a rectangular pattern. Such a detector is capable of measuring the two Cartesian components of the flux gradient vector in the horizontal plane. This paper presents an initial evaluation of the detector design, through Monte Carlo simulations in a hypothetical scenario.

Light guiding fiber

Monte Carlo

Neutron flux gradient detector

Scintillation detector

Author

Moad al-Dbissi

Belgian Nuclear Research Center (SCK CEN)

Chalmers, Physics, Subatomic, High Energy and Plasma Physics, Subatomic, High Energy and Plasma Physics PP

Paolo Vinai

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Alessandro Borella

Belgian Nuclear Research Center (SCK CEN)

Riccardo Rossa

Belgian Nuclear Research Center (SCK CEN)

Imre Pazsit

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

0168-9002 (ISSN)

Vol. 1026 166030

Subject Categories

Accelerator Physics and Instrumentation

Subatomic Physics

DOI

10.1016/j.nima.2021.166030

More information

Latest update

1/10/2022