Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2609.35785

The efficiency of moderating neutron detector: Monte Carlo simulation, experimental validation, and angular dependence

Carl R. Brune
View original source ↗Read source document ↗Export metadata ↓

Abstract

This paper describes the Monte Carlo simulation and experimental validation of the neutron detection efficiency in a 4pi polyethylene moderating detector. The experimental validation was performed using several sources providing neutron energies from 10s of keV up to 14 MeV. The Monte Carlo simulations employed the MCNP6 code are believed to be accurate within 3% for neutron energies below 6 MeV. A new method for parametrizing the dependence of the efficiency on the neutron angular distribution for in-beam experiments is also presented. This approach utilizes a Legendre decomposition of the efficiency and allows all of the needed information to be extracted from a single simulation.

Explore related subjects

physics.ins-detnucl-ex

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Carl R. Brune. 2026-08-27. The efficiency of moderating neutron detector: Monte Carlo simulation, experimental validation, and angular dependence. https://arxiv.org/abs/2609.35785

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Three-dimensional Compton imaging of undepleted volumes of germanium detectors

The shape of the undepleted volume of a p-type Broad Energy Germanium detector has been imaged at various bias voltages by measuring spatially-resolved three-dimensional Compton-scattering efficiency. The bias voltage was raised stepwise from $-50\,\text{mm}$ to the full-depletion voltage.The geometric acceptance was determined at full depletion. Below full depletion, the relative acceptance observed for $2\times2\times2\,\text{mm}^3$ voxels was used to create the image of the undepleted volume for each bias voltage. The images were fitted with predictions from the open-source software package SolidStateDetectors$.$jl to extract the radial impurity density profile of the detector. The strong radial decrease in the impurity density obtained in the outermost centimeter was validated using independent capacitance measurements. This novel method to determine the impurity density via three-dimensional Compton-scattering efficiency maps provides a powerful tool for advanced detector bulk characterization.

physics.ins-det↗
arXiv2026

Development and Performance Study of a Capillary Liquid Scintillator Neutron Detector

Capillary liquid scintillator detectors are promising for high-resolution neutron imaging, yet experimental data on their light spread mechanism and spatial performance remain limited. Here, we report a neutron detector based on a hexagonal capillary array filled with EJ-309 liquid scintillator, with an inner diameter of about 50 um and a camera readout of 9 um pixels. Laser experiments show that the FWHM of the full light spot decreases from 260 um to 90 um with a metal light absorber, confirming effective suppression of lateral light spread. Using an AmBe neutron source, an effective field of view with a 5-sigma threshold was established from background frames. For single-capillary events, the pulse height spectrum follows a Landau distribution with a most probable value of 0.133 +/- 0.001 (stat.), and the intrinsic detection efficiency is 10.07% +/- 1.26% (stat.) +/- 1.43% (syst.), corresponding to about 13.55% when normalized to the active liquid scintillator area. The point spread function core yields a radial FWHM of 12.8 um and a centroid positioning precision of approximately 5.5 um (1 sigma), while the intrinsic position resolution is limited by the capillary pitch to 54 um. Linearity is good for 1 to 2 capillaries, with deviation appearing for 2 to 3 capillaries due to additional capture of spread light. These results provide experimental basis and physical understanding for imaging applications of capillary liquid scintillator neutron detectors.

physics.ins-det↗
arXiv2026

Quantitative Interleaved-Pulse Acquisition Extends the Range of Isotope-Ratio Measurements in ToF-SIMS

Isotope ratios underpin tracer studies of transport in oxides, battery materials, and biological systems, yet time-of-flight secondary ion mass spectrometry (ToF-SIMS) struggles to quantify ratios whose members differ in intensity by orders of magnitude: a primary-ion pulse long enough to count the minor isotope precisely can saturate the major isotope, whereas a pulse short enough to keep the major isotope linear yields too few minor-isotope counts. We show that multi-pulse-width acquisition yields quantitative isotope ratios when a dose factor measured within each crater links the phases and each isotope is taken only from phases in which it remains linear; we call this quantitative reconstruction interleaved-pulse acquisition. Pulse widths are selected from measured transfer curves and peak shapes. On thermal SiO2, a tuned (6, 35) ns pair achieves the same per-layer precision as short-pulse acquisition with a 13-fold reduction in the number of analysis frames. On 18O-enriched WOx films, interleaving extends the quantifiable range at the low-fraction end by about 14-fold. Across isotope ratios spanning approximately 1:500 to 1:1, the interleaved reconstruction agrees with the corresponding linear reference measurements, showing no measurable bias introduced by interleaving, and natural-abundance ratios of oxygen, strontium and titanium are reproduced within several percent. The method requires no hardware additions and enables depth-resolved isotope-ratio measurements over a wide range within a single crater.

physics.ins-det↗