Prompt Gamma Neutron Activation Analysis Research Articles

Development of a Compact Deuterium–Deuterium Neutron Generator for Prompt Gamma Neutron Activation Analysis

A compact deuterium–deuterium neutron generator for prompt gamma neutron activation analysis was developed at Institute of Nuclear Physics and Chemistry. A neutron yield of 3.6 × 108 s–1 was achieved during of the bombardment of a titanium drive-in target by a 6.8 mA deuteron beam at 115 keV. The deuteron beam was generated by a permanent magnet microwave ion source. An 85 h long run with 1.2 × 108 s–1 average neutron yield was performed at 85 keV and 3.7 mA. The operating mode of the neutron generator reached 99.95%.

Detecting shielded explosives by coupling prompt gamma neutron activation analysis and deep neural networks

Prompt Gamma Neutron Activation Analysis is a nuclear-based technique that can be used in explosives detection. It relies on bombarding unknown samples with neutrons emitted from a neutron source. These neutrons interact with the sample nuclei emitting the gamma spectrum with peaks at specific energies, which are considered a fingerprint for the sample composition. Analyzing these peaks heights will give information about the unknown sample material composition. Shielding the sample from gamma rays or neutrons will affect the gamma spectrum obtained to be analyzed, providing a false indication about the sample constituents, especially when the shield is unknown. Here we show how using deep neural networks can solve the shielding drawback associated with the prompt gamma neutron activation analysis technique in explosives detection. We found that the introduced end-to-end framework was capable of differentiating between explosive and non-explosive hydrocarbons with accuracy of 95% for the previously included explosives in the model development data set. It was also, capable of generalizing with accuracy 80% over the explosives which were not included in the model development data set. Our results show that coupling prompt gamma neutron activation analysis with deep neural networks has a good potential for high accuracy explosives detection regardless of the shield presence.

Quantification of boron contents in BN/BCN composites by prompt gamma-ray neutron activation analysis utilizing thermal neutron beam at Dhruva reactor

Samples of boron (B) doped g-C3N4 (BCN) and boron nitride (BN) composite (BN/BCN) were synthesized by a simple in situ technique by varying BN content in the range of 1–10% mass fraction and boron contents are crucial for improving the activity of the composites. The composites were characterized by PXRD and FTIR in order to confirm their successful formation. Prompt Gamma Neutron Activation Analysis (PGNAA) using thermal neutron beam from Dhruva reactor was used for non-destructive determination of total boron concentration by measuring 478 keV prompt gamma-ray from 10B (n, αγ)7*Li reaction. The obtained boron concentrations are in the range of 2.3–6.2% mass fraction.

GEOSCAN-M Use For Process Improvement in Phosphate Plants

Real-time on belt analysis of minerals is becoming increasingly important in mining operations to ensure optimal economic outcomes. Prompt gamma neutron activation analysis has long been utilised for real-time elemental analysis in bulk materials, with Scantech’s GEOSCAN being the instrument of choice in the minerals sector. The GEOSCAN has been successfully adapted to a wide range of commodities, with its use in the phosphate sector one of the fastest growing areas for use of the technology. Using data for both feedback and feedforward control has seen improvements in efficiency at the mine, at the beneficiation plant, and in the production of phosphoric acid and fertiliser products. This paper introduces the GEOSCAN for the phosphate industry, and provides a case study for its use at an example Middle Eastern plant. A series of results are provided for various applications, demonstrating the instrument’s performance, and some of the key benefits of the equipment are discussed.

Processing scintillation gamma-ray spectra by artificial neural network

Elemental analysis can be performed using obtained gamma-ray spectrum of the sample under study. In this work, simple Multi-Layer Perceptron (MLP) neural network models are proposed for analyzing a gamma-ray emitting sample using whole information of its obtained gamma-ray spectrum. Elemental analysis is performed in two fields of study using 3 × 3 inch NaI(Tl) detectors: Radio-Isotope Identification (RIID) and Prompt Gamma Neutron Activation Analysis (PGNAA). The gamma-ray point sources are used for an empirical study in RIID field, while a Monte Carlo simulation study is considered for determining chlorine and water content of crude oil using combination of PGNAA technique and a MLP model. According to the obtained results of both empirical and simulation studies, the proposed ANN models are appropriate for elemental analysis using whole gamma-ray spectral information of sample under study.

PIBS: Proton and ion beam spectroscopy for in vivo measurements of oxygen, carbon, and calcium concentrations in the human body

Proton and ion beam therapy has proven to benefit tumour control with lower side-effects, mostly in paediatrics. Here we demonstrate a feasible technique for proton and ion beam spectroscopy (PIBS) capable of determining the elemental compositions of the irradiated tissues during particle therapy. This follows the developments in prompt gamma imaging for online range verification and the inheritance from prompt gamma neutron activation analysis. Samples of water solutions were prepared to emulate varying oxygen and carbon concentrations. The irradiation of those samples and other tissue surrogate inserts by protons and ion beams under clinical conditions clearly showed a logarithmic relationship between the target elemental composition and the prompt gamma production. This finding is in line with the known logarithmic dependence of the pH with the proton molar concentration. Elemental concentration changes of 1% for calcium and 2% for oxygen in adipose, brain, breast, liver, muscle and bone-related tissue surrogates were clearly identified. Real-time in vivo measurements of oxygen, carbon and calcium concentrations will be evaluated in a pre-clinical and clinical environment. This technique should have an important impact in the assessment of tumour hypoxia over the course of several treatment fractions and the tracking of calcifications in brain metastases.

Preliminary study of prompt gamma neutron activation analysis for Melamine

Prompt gamma neutron activation (PGNA) technique can be applied for detecting explosives in hidden places by using spontaneous fission source 252Cf source or neutron generator that emits thermal and cold neutrons. Some of emitted neutrons will be captured by nuclei and results in production of prompt gamma rays. Explosive materials can be identified by observing prompt gamma energy spectrum using high purity germanium (HPGe) detector. Gamma energy peaks indicate the presence of corresponding explosive nuclei in scanned materials. This paper describes the experiments conducted to investigate the possibility of explosive detection by using PGNA with 241Am/Be neutron source and limitations that come with it.

Comparison of active interrogation methods for source location in a scattering and absorbing medium, consisting of PGNAA, and an AmBe quasi-forward biased directional source

Source location of Special Nuclear Material (SNM) encompassing 95% 235U and 239Pu is identified by utilizing a directional source from Patent No: US20190013109A1 using Prompt Gamma Neutron Activation Analysis (PGNAA) and neutron spectroscopy simulated with Monte-Carlo N-Particle transport 6.2 (MCNP). BC-408, HPGe, LaBr3 detector arrays were used to identify the location of the SNM using total counts incident on each detector, and PGNAA photopeaks from HPGe and LaBr3 detector arrays in a polyethylene shield. The conducted simulations varied the volume and location of the SNM in the MCNP input files to observe how the source location method behaved. PGNAA photopeaks used for source identification include 61keV from fission, 2.223MeV prompt gamma from hydrogen, 511keV annihilation, and a single and double escape peaks from the prompt gamma interaction from hydrogen. The capabilities of each detector systems to acquire well resolved photopeaks with a 1% relative error or less, and total relative error for F4 and F8 tallies were less than 0.015% relative error. Source predictions of the SNM with uneven amounts of polyethylene shielding between the source and detectors was observed to overpredict and give invalid source location predictions. Source locations of the SNM with even amounts of polyethylene material between the source and each detector were found to be valid. With a 1Ci 241Am source activity, it was determined that 1630s were needed to obtain the results for each detector system with the quasi-forward directional AmBe source. Coupling source and material identification together would increase acquisition time but would only require one system to determine.

Fluka simulation of PGNAA system for determining heavy metal pollution in the soil sample

Abstract This study presented a self-designed prompt gamma neutron activation analysis (PGNAA) model and used Fluka simulation to simulate the heavy metals (Mn, Cu, Hg, Ni, Cr, Pb) in soil samples. The relationship between the prompt γ -ray yield of each heavy metal and soil thickness, content of heavy metals in the soil, and source distance was obtained. Simulation results show that the prompt γ -ray yield of each heavy metal increases with the increase in soil thickness and reaches saturation at 18 cm. The greater the proportion of heavy metals in the soil, the greater the prompt γ -ray yield. The highest content is approximately 3%, and the change in distance between the neutron source and soil sample does not affect the prompt γ -ray yield of heavy metals.

Quantification of trace amounts of transmuted nuclides in transmutation detectors using SIMS

Neutron detectors based on neutron induced transmutation of nuclides of high-purity materials into other stable nuclides has been recently proposed to improve accuracy of long-term measurement of neutron fluence in fission nuclear reactors. The inductively coupled plasma mass spectrometry (ICP-MS) and the prompt gamma neutron activation analysis (PGNAA) have been used for the measurement of concentration of transmuted nuclides, which was then converted into neutron fluence using known neutron-reaction cross sections.In this work, the concentrations of transmuted elements were measured with a magnetic-sector secondary ion mass spectrometer (SIMS) instead of ICP-MS or PGNAA. Single crystals of Si, Ge and a polycrystalline metal foil of Ni were used as detector materials. The concentrations were measured down to sub ppb range in Si and Ge crystals. 9 prospective nuclides for transmutation detectors — 25Mg, 26Mg, 27Al, 31P, 67Zn, 69Ga, 71Ga, 59Ni, 63Ni were measured and compared to a reference neutron activation detector (NAD) method with neutron reaction cross section values taken from two different databases. With exception of 26Mg, the values determined using SIMS were within 20 % compared to those obtained using NADs with a cross section value from one or both databases. In case of 26Mg the difference between the results of SIMS and NAD methods was higher than 45 % for data from both databases. This discrepancy for 26Mg measurement was assigned tentatively to uncertainties of the neutron reaction cross section values. Nevertheless, the experiments proved distinct advantages of SIMS over ICP-MS in sample preparation and throughput, and in consuming micro-volumes of material and identified at least one well performing transmutation detector for thermal neutrons (Ge - single crystal) with agreement within 3 % between SIMS-TMD and NADs.

Overview of Industrial Materials Detection Based on Prompt Gamma Neutron Activation Analysis Technology

Prompt gamma neutron activation analysis (PGNAA) is a non-destructive online measurement nuclear analysis method. With its unique advantages, it has been widely used in online analysis of industrial materials such as coal, cement, and minerals in recent years. However, there are many kinds of literature on PGNAA in the field of industrial materials detection, and there are still a few concluding articles. To this end, based on the principle of PGNAA online analysis, the status quo and development of the real-time online detection of industrial material components in the field are reviewed and discussed by consulting a large number of domestic and foreign PGNAA related literature and data, to facilitate the reference of relevant scientific researchers.

Study of a collimation method as a nondestructive diagnostic diagnostic technique by PGNAA for salt distribution in concrete structures at RANS

To meet strong demand for realizing an effective tool to diagnose salt distribution in concrete infrastructures, we have started a development of a new technique using a prompt gamma neutron activation analysis (PGNAA) at the RIKEN accelerator-driven compact neutron source (RANS). So far, by applying PGNAA we have experimentally confirmed that neutrons from RANS can detect small enough amounts of chlorine within the marginal concentration of around 1.2 kg/m3 to involve steel corrosion. In this study, we have proposed two methods to derive the salt depth profile which is critical information of steel corrosion start. The first one utilizes a difference in the intensity ratio of two different γ-ray energies of interest, which is depending on the depth where the neutron capture reaction arises inside the concrete. The second is called the collimator method that measure γ-rays coming through a collimator around detector. Detection of γ-ray associated with 35Cl coming from the assembly of concrete has been also simulated with conditions of neutrons from RANS and a collimator. The feasibility of the method was discussed.

Conceptual implementation stages for Moroccan PGAA/NI instruments: STAGE I & II

The first installation around the tangential beam tube of the Moroccan TRIGA Mark II research reactor comprises combined instruments for Prompt Gamma Neutron Activation Analysis (PGAA) and Neutron Imaging (NI). The implementation of this project is divided over three main stages, namely the installation of the collimator and the primary beam shutter, which is a common section for introduction inside the reactor; the PGAA instruments’ installation; and finally, the installation of the PGNAA/NI combined instruments. The entire design was planned for this project, and detailed information about the first and the second stage is described in this work.

Collimator and sapphire filter using for the prompt gamma neutron activation analysis facility: modelling and simulation

Safety measures play an important role in ensuring any system, although nuclear systems always require more safeguards than necessary. From this principle comes the importance of this research, which aims to conduct a study of neutron simulations and modelling to ensure safe installation of PGAA devices in the NB1 channel from the TRIGA Research Reactor at the Maamoura Center for Nuclear Studies. During this study, we used the Monte Carlo method using the MCNP6/X code. This study aims to determine the neutron profile, neutron distribution, and secondary gamma rays produced during the passage of the neutron flux in the collimator channel, sapphire and the vacuum channel that is maintained for the immediate neutron activation analysis (PGAA).

MCNP optimization of fast neutron beam thermalization device based on D-T neutron generator

The 14 MeV neutrons generated by Deuterium-Tritium (D-T) fusion reaction usually need to be moderated for Prompt Gamma Neutron Activation Analysis (PGNAA) applications. A fast neutron beam thermalization device was developed in Northeast Normal University based on a D-T neutron generator (model NG-9). A simple experimental system was set up firstly to validate the feasibility of simulation. The materials and dimensions of moderator and the size of multiplier, reflector and collimator were then optimized through MCNP5 to improve the efficiency of the thermalization device. The thermal, epithermal, fast and total neutron flux across the output surface in final system were increased for a factor of 9.65, 8.70, 5.84 and 6.94 times compared to the initial experimental system, respectively. And the optimized thermalization efficiency is 13.28 times higher than that of the original model of experimental system.

Active interrogation of Special Nuclear Material containers using AmBe quasi-forward biased directional source and PGNAA

Special Nuclear Material (SNM) including 95% 235U and 239Pu is capable of being identified by utilizing a quasi-forward directional AmBe source from Patent No: US20190013109A1 using Prompt Gamma Neutron Activation Analysis (PGNAA) simulated with Monte-Carlo N-Particle transport 6.2 (MCNP). HPGe and LaBr3 detector arrays were used to identify and quantify the peak-to-background and peak-to-total ratios of the associated photon spectra from the SNM encased in a polyethylene shield. The conducted simulations varied the volume of the SNM and neutron source strength in the MCNP data card to conduct an uncertainty analysis. Photopeaks identified include K-shell X-rays from 235U and 239Pu, 61 keV from fission, 2.223 MeV prompt gamma from hydrogen, 511 keV annihilation, and a single and double escape peak from the prompt gamma interaction from hydrogen. Relationships between peak-to-total and peak-to-background as a function of SNM and particle history were investigated to aid in the analysis. The capabilities of both detector systems to acquire well resolved photopeak with a 5% relative error or less, with a 1 Ci source activity, and a peak-to-background ratio of 1.15. This was determined to take 326 s for LaBr3 and 163 s for HPGe which is comparable to current methods for material detection which take between 100 and 900 s to acquire.

Application of the collective model to determine some vibrational bands of 140La nucleus

140La is created from the thermal neutron capture reaction of 139La, which is the product of the fission reaction. It makes some effects into the components of the nuclear reactor core. Understanding the properties and structure of 140La is important in operating the nuclear reactor. Besides that, nuclear structure models are very effective in explaining the properties of nuclear structure. There are many nuclear structure models to solve those problems, such as Liquid Drop Model, Shell Model, Fermi Model, etc. Among them, the Collective Model has been very successful in describing the variety of nuclear properties, especially energy levels in deformed nuclei that the Shell Model and the Liquid Drop Model does not apply. This paper presents the application of the Collective Model to determine some vibrational bands of 140La nucleus. This experiment is performed at channel No.2 of Dalat Research Reactor (DRR), Prompt gamma neutron activation analysis method (PGNAA) is used. The result has found 8 vibrational bands of 140La nucleus. It’s quite relevant to the theoretical calculation. The deviations are less than 1.6 %.

Matrix effects corrections in prompt gamma-ray spectra of a PGNAA online analyzer system using artificial neural network

One of the well-known online monitoring techniques used for quality control of bulk samples is Prompt Gamma Neutron Activation Analysis (PGNAA). PGNAA suffers from the so-called matrix effect problems such as density, thickness and moisture content of the sample under study. In this work, an Artificial Neural Network (ANN) model is introduced to deal with these effects. The required spectra for training and testing the proposed ANN model are obtained by Monte Carlo simulation of the gamma-ray spectra recorded in a PGNAA online analyzer system used in cement factories. The gamma-ray spectra related to given set of density, thickness and moisture content are corrected channel-to-channel using the proposed ANN model. The corrected spectra are then compared against the standard spectra obtained for predefined standard density, thickness and moisture content. The improvement in Theil coefficient is larger than 70% for the tested spectra.

Characterization of Neutron and Gamma Beams at the TRIGA 2000 Reactor Beam Ports Using Monte Carlo

Neutron and gamma beams characterization at the beam ports of TRIGA 2000 reactor was done in order to prepare the development of Prompt Gamma Neutron Activation Analysis (PGNAA) facility. Characterization was performed by simulation using Monte Carlo method with MCNPX and PHITS computer codes. The MCNPX code is used to simulate the neutron-gamma fluence and spectra of the reactor core from fission reactions. The PHITS code is used to simulate the distribution of the neutron-gamma fluence in the beam ports. The simulation was done by modeling the geometry and elemental composition of reactor material and radiation source model in the form of fission reaction in the reactor core. This results will be used to select the most suitable one of the four beam ports for the PGNAA use, based on the prescribed requirements, such as the neutron spectral characteristics and neutron-gamma fluence ratio at the beam port’s outlet. The results indicate that the tangential beam port provides better characteristics of neutron spectrum and neutron-gamma fluence ratio so become most suitable for PGNAA facility.

Compositional Analysis of Cement Raw Meal by Near-Infrared (NIR) Spectroscopy

A rapid and accurate method is presented to determine CaCO3, SiO2, Fe2O3, and Al2O3 in cement raw meal using near-infrared (NIR) spectroscopy. Multiplicative scatter correction (MSC) was employed to eliminate the scattering signal and partial least squares (PLS) regression was used to build the analysis model. The results demonstrated good performance by this approach for the determination of CaCO3, SiO2, Fe2O3, and Al2O3. NIR spectroscopy exhibits the feasibility to characterize the quality of cement raw meal. Compared with prompt gamma neutron activation analysis (PGNAA) and X-ray fluorescence (XRF), this method is more efficient and safer.