Large solubility of lithium carboxylates reaching high rates of 6Li incorporation in polystyrene-based plastic scintillators for fast/thermal neutron and gamma ray detection

2019 ◽  
Vol 3 (8) ◽  
pp. 1626-1631 ◽  
Author(s):  
Camille Frangville ◽  
Matthieu Hamel ◽  
Guillaume H. V. Bertrand ◽  
Eva Montbarbon ◽  
Amélie Grabowski ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Homeland Security ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Thermal Neutrons ◽  
Plastic Scintillators

6Li-Doped plastic scintillators (PSs) have been optimized as radioluminescent sensors for detection of fast/thermal neutrons and gamma rays for several purposes such as homeland security.

6Li210B4O7 NPs-loaded plastic scintillators for fast/thermal neutron and gamma ray detection

2019 ◽  
Vol 3 (8) ◽  
pp. 1574-1579
Author(s):  
Camille Frangville ◽  
Amélie Grabowski ◽  
Jonathan Dumazert ◽  
Eva Montbarbon ◽  
Clément Lynde ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Homeland Security ◽  
Gamma Ray ◽  
Plastic Scintillators

We report herein the synthesis of a new series of plastic scintillators (PSs) loaded with 6Li210B4O7 nanoparticles (NPs), as new radioluminescent sensors for fast/thermal neutron and gamma ray detection in the critical context of homeland security.

Gamma-ray sensitivity and shielding of a neutron imaging plate

1999 ◽  
Vol 32 (5) ◽  
pp. 878-882 ◽  
Author(s):  
Y. Karasawa Haga ◽  
S. Kumazawa ◽  
N. Niimura
Keyword(s):  
Thermal Neutron ◽  
Energy Dependence ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Neutron Imaging ◽  
Atomic Energy ◽  
Imaging Plate ◽  
Energy Research ◽  
Experimental Hall ◽  
Lead Foil

The energy dependence of gamma-ray sensitivity of a neutron imaging plate (NIP) has been measured. The gamma-ray sensitivity is equivalent to one half that of a thermal neutron at a gamma-ray energy less than 300 keV, and 1/40 at greater than 300 keV. The shielding of the NIP, by lead, from gamma rays in the experimental hall of the reactor JRR-3M of the Japan Atomic Energy Research Institute (JAERI) was measured. It was found that lead of thickness 40 mm is sufficient to reduce the gamma-ray background to 1/10 on a normalized scale. Covering the NIP with lead foil of thickness 1 mm results in a decrease of the gamma-ray background without reduction of the neutron signal.

scholarly journals Methodology and algorithm to correct the thermal neutron porosity for the effect of rare elements and rock minerals with high neutron absorption probability

2021 ◽  
Author(s):  
Moustafa Oraby
Keyword(s):  
Thermal Neutron ◽  
Gamma Ray ◽  
Neutron Transport ◽  
Thermal Neutrons ◽  
Neutron Absorption ◽  
Transport Parameters ◽  
Rare Element ◽  
Absorption Probability ◽  
Rare Elements ◽  
Neutron Porosity

AbstractThe thermal neutron porosity is routinely acquired in almost every well. When combined with the density, gamma ray and resistivity logs, the basic petrophysical parameters of a reservoir are evaluated. The design of the thermal neutron tool is simple, but its interpretation is complex and affected by the formation constituents. The most challenging situation occurs when the formation contains elements with high absorption probability of the thermal neutrons. The existence of such elements changes the neutron transport parameters and results in a false increase in the measured porosity. The problem is reported by many users throughout the years. In 1993, higher thermal neutron porosity is reported due to the existence of an iron-rich mineral, Siderite, in the Nazzazat and Baharia formations in Egypt. Siderite and all iron-rich minerals have high thermal neutrons absorption probability. Recently, in 2018, high thermal neutron porosity in Unayzah field in Saudi Arabia is also reported due to the existence of few parts per million of gadolinium. Gadolinium is a rare element that has high probability of thermal neutron absorption. Currently, none of the existing commercial petrophysics software(s) have modules to correct the thermal neutron porosity for such effects. This represents a challenge to the petrophysicists to properly calculate the actual reservoir porosity. In this paper, the effects of the rare elements and other minerals with high thermal neutron absorption probability on the thermal neutron porosity are discussed, and a correction methodology is developed and tested. The methodology is based on integrating the tool design and the physics of the neutron transport to perform the correction. The details of the correction steps and the correction algorithm are included, tested and applied in two fields.

THE 199Hg(n, γ)200Hg REACTION WITH THERMAL NEUTRONS

1967 ◽  
Vol 45 (4) ◽  
pp. 1517-1540 ◽  
Author(s):  
G. A. Bartholomew ◽  
S. I. H. Naqvi ◽  
M. R. Gunye ◽  
E. D. Earle
Keyword(s):  
Thermal Neutron ◽  
Angular Correlation ◽  
Level Scheme ◽  
Neutron Capture ◽  
Gamma Ray ◽  
Germanium Detector ◽  
Thermal Neutrons ◽  
Thermal Neutron Capture ◽  
Γ Rays ◽  
Correlation Techniques

Thermal neutron-capture γ rays from 199Hg(n, γ)200Hg were studied with a lithium germanium detector and with angular correlation techniques. Gamma-ray and level energies were determined with accuracies of at best ±3 keV. Spin 0 for the capturing state was confirmed and levels at 1 569, 2 060, 2 369, 2 640, 3 186, 3 269, 3 289, 3 351 keV were assigned spin 1. The 200Hg level scheme is discussed.

scholarly journals Sorting fission from parasitic coincidences of neutrons and gamma rays in plastic scintillators using particle times of flight

2021 ◽  
Vol 253 ◽  
pp. 07014
Author(s):  
V. Bottau ◽  
C. Carasco ◽  
B. Perot ◽  
C. Eleon ◽  
R. De Stefano ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Spontaneous Fission ◽  
Gamma Ray ◽  
Detection Efficiency ◽  
Region Of Interest ◽  
Processing Technique ◽  
Pulse Shape Discrimination ◽  
Pulse Detection ◽  
Plastic Scintillators ◽  
Neutron Detection Efficiency

This work addresses the use of plastic scintillators as an alternative to 3He detectors for radioactive waste drum characterization. The time response of scintillators is three orders of magnitude faster than that of gas proportional counters and they offer similar neutron detection efficiency at lower cost. However, they are sensitive to gamma rays and the commonly used Pulse Shape Discrimination technique is not possible with basic PVT scintillators. This paper reports on an innovative data processing technique allowing to extract spontaneous fission events from parasitic coincidences, such as those from the (α,n) reactions accompanied by correlated gamma rays or from pure gamma-ray sources emitting correlated radiations. The proposed approach makes advantage of differences in the pulse detection times recorded in measurements with the 252Cf, AmBe and 60Co sources. More precisely, a 2D histogram of time delays between the detected 2nd and 1st pulses, on the x-axis, and between the 3rd and 2nd pulses, on the y-axis, is found to allow for selection of a region of interest most relevant to spontaneous fission events.

scholarly journals Study of gamma-ray background noise for radioactive waste drum characterization with plastic scintillators

2020 ◽  
Vol 225 ◽  
pp. 05004
Author(s):  
V. Bottau ◽  
L. Tondut ◽  
P.G. Allinei ◽  
B. Perot ◽  
C. Eleon ◽  
...  
Keyword(s):  
Radioactive Waste ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Detection Efficiency ◽  
Fission Neutron ◽  
High Energy ◽  
Fast Neutrons ◽  
Coincidence Counting ◽  
Useful Signal ◽  
Plastic Scintillators

In the framework of the radioactive waste drum characterization using neutron coincidence counting, the Nuclear Measurement Laboratory of CEA Cadarache is studying plastic scintillators as an alternative to ideal but costly 3He gas proportional counters. Plastic scintillators are at least 5 times cheaper for the same detection efficiency, and in addition, they detect fast neutrons about three orders of magnitude faster than 3He detectors. However, they are sensitive to gamma rays, which implies the necessity to identify precisely gamma background sources that may affect the useful signal. This paper presents a detailed analysis of the gamma-ray spectrum of a radioactive waste drum containing glove box filters contaminated by plutonium dioxide. Gamma emissions accompanying inelastic scattering (n,n’) and (α,n) reactions that can lead to neutron-gamma coincidences parasitizing useful coincidences from plutonium spontaneous fissions are identified. Some of these parasitic gamma rays having energies up to several MeV, we plan to reject high-energy scintillator pulses with an electronics rejection threshold above 1 MeV, which should preserve the major part of useful fission neutron pulses.

Vulcanization of SBR in a Thermal Neutron Field

1960 ◽  
Vol 33 (4) ◽  
pp. 1083-1091
Author(s):  
Herbert R. Anderson
Keyword(s):  
Boron Nitride ◽  
Thermal Neutron ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Neutron Field ◽  
Energy Utilization ◽  
Rubber Compound ◽  
Helium Atmosphere ◽  
Residual Radioactivity

Abstract The nuclear reactions B10(n,α)Li7* and Li6(n,α)H3 can be used to generate highly ionizing particles in a pure thermal neutron field to vulcanize an otherwise transparent rubber compound. Vulcanizates have satisfactory physical properties comparable with those produced by other means of vulcanization, e.g., gamma rays and peroxides. Such vulcanizates possessed negligible residual radioactivity. The somewhat analogous initiating systems gave vastly different vulcanizates with the same parent rubber compound in a helium atmosphere, and a possible explanation is presented. The G values for lithium methoxide promotion (ca. 3) are comparable with those obtained with gamma-ray vulcanizates. Promotion is less efficient with boron nitride, the average values of G being approximately 0.9. The irradiation atmosphere has a pronounced influence on the type of vulcanizate produced and on the energy utilization. Substitution of air for helium as the irradiation atmosphere increases net crosslinking of cold rubber with boron nitride promotion, while it decreases it when lithium methoxide is used as the promoter.

Rapid forward modeling of multidetector logging-while-drilling Sigma measurements

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. D253-D273 ◽  
Author(s):  
Edwin Ortega ◽  
Carlos Torres-Verdín ◽  
William E. Preeg
Keyword(s):  
Monte Carlo ◽  
Thermal Neutron ◽  
Gamma Ray ◽  
Simulation Method ◽  
Accurate Method ◽  
Late Time ◽  
Thermal Neutrons ◽  
Neutron Absorption ◽  
Logging While Drilling ◽  
Time Required

Multidetector logging-while-drilling (LWD) Sigma was introduced to the oil industry to measure neutron absorption cross section (Sigma) and radial length of invasion in shallow-invaded formations. Sigma quantifies the ability of a material to absorb thermal neutrons and is calculated from the late time portion of the time decay of thermal neutrons or gamma rays generated from thermal-neutron absorption. The assessment of invasion is made possible with the combination of a thermal-neutron detector and two gamma-ray detectors with different source-detector spacings. However, the interpretation of LWD Sigma logs is often affected by several environmental and/or geometric effects that can mask the formation response. A fast numerical simulation method embedded with inversion-based techniques can be used to estimate intrinsic formation Sigma from borehole measurements affected by shoulder-bed, invasion, and/or environmental effects. We developed a fast and accurate method to numerically simulate LWD multidetector thermal-neutron and gamma-ray time decays in realistic borehole environments. The method relies on Monte Carlo precalculated libraries of particle time decays and detector-specific flux sensitivity functions, while accounting for detector-specific borehole and diffusion effects. Simulations are benchmarked against test-pit measurements and Monte Carlo N-particle (MCNP) transport code calculations. Results indicate that multidetector time decays acquired under complex geometrical conditions can be numerically simulated in approximately 1e-5 the time required using MCNP, with average difference within two capture units. The simulation of time decays, rather than Sigma itself enables a direct relationship between actual rock Sigma and multidetector diffusion-affected time decays, thereby removing intermediate correction steps often used to convert apparent into intrinsic formation Sigma.

scholarly journals Nitrogen Detection in Bulk Samples Using a D-D Reaction-Based Portable Neutron Generator

2013 ◽  
Vol 2013 ◽  
pp. 1-7
Author(s):  
A. A. Naqvi ◽  
Faris A. Al-Matouq ◽  
F. Z. Khiari ◽  
M. A. Gondal ◽  
A. A. Isab ◽  
...  
Keyword(s):  
Excellent Agreement ◽  
Gamma Rays ◽  
Neutron Generator ◽  
Gamma Ray ◽  
Nitrogen Concentration ◽  
Prompt Gamma ◽  
Thermal Neutrons ◽  
Satisfactory Performance ◽  
Nitrogen Detection ◽  
Detector Material

Nitrogen concentration was measured via 2.52 MeV nitrogen gamma ray from melamine, caffeine, urea, and disperse orange bulk samples using a newly designed D-D portable neutron generator-based prompt gamma ray setup. Inspite of low flux of thermal neutrons produced by D-D reaction-based portable neutron generator and interference of 2.52 MeV gamma rays from nitrogen in bulk samples with 2.50 MeV gamma ray from bismuth in BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays indicates satisfactory performance of the setup for detection of nitrogen in bulk samples.

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