Prompt Gamma Activation Analysis Research Articles

Transparency at its best: neutrons probing archaeological glass finds from Romania

This paper demonstrates the suitability of Prompt Gamma Activation Analysis (PGAA) technique for the compositional study of ancient glass finds, illustrating this idea by presenting and commenting the chemical composition of 41 Roman glass fragments discovered in archaeological excavations at Tomis, Histria, and Beidaud, Romania. According to typological and stratigraphic criteria, most finds were dated to the 1st-4th centuries AD. The PGAA measurements were performed at the Budapest Neutron Centre (BNC), Hungary. Regardless of their color (or the lack of it), most of the analyzed vitreous items have compositional traits often encountered in coeval glass artefacts discovered at various sites all over the Roman Empire. The sample set turned out to include several examples of Foy Série 2.1 and a single HIMT glass item, in agreement with the later chronological attribution of the corresponding fragments. This study provides some information about the chemistry of the Roman glass finds unearthed during the archaeological research performed in the region of the western Black Sea coast.

Prompt gamma activation analysis for boron determination in the tens of milligram range at the HOTNES facility

Boron is an elective element for the Prompt Gamma Activation Analysis (PGAA), due to its exceptionally large neutron capture cross section. This technique, usually performed in nuclear reactors with neutron fluxes as high as 108 cm−2 s−1, can determine quantities of boron as low as tens of nanograms. Some applications, such as the industry of neutron shielding materials, would better benefit from a less sensitive but more portable and accessible boron PGAA, which could be established at construction or fabrication sites. For these purposes ENEA and INFN jointly setup a compact PGAA based on a 0.5 cm3 Cadmium–Zinc–Telluride gamma spectrometer and the HOTNES thermal neutron source. Relying on a series of borated resins with known composition and on comprehensive experimental and Monte Carlo evaluations, this technique features a detection limit in the order of few milligrams in terms of boron mass. As the facility consists simply on a lab-scale neutron source and a polyethylene block with well-established geometry, this simplified PGAA system is suited to be replicated or transported to construction or fabrication sites for QA/QC purposes on borated construction materials for the nuclear sector.

Temperature distribution in the PGAA system: Collimator, shutter, and filter in TRIGA Mark II reactor

This article examines the impact of temperature on the steel collimator cap and the primary beam shutter. These components will be used to implement the Prompt Gamma Activation Analysis (PGAA) technique in the Moroccan TRIGA Mark-II research reactor. The steel collimator plug is essential for forming the neutron beam, while the main role of the shutter is to stop the beam when the channel is inactive. This study analyzes the effect of temperature on the collimator and shutter system, particularly focusing on the variation in maximum temperature over a month of operation with 8-h cycles per day, the behavior of temperature over 24 h, the total heat flux as a function of the length of the experimental device, the temperature distribution in mild steel (E235) and 304L stainless steel materials, and the total displacement and strain gradient as a function of temperature. All calculations were performed using COMSOL Multiphysics simulation software, based on the finite element method.

A Comprehensive Study on the Effect of Washing on Nickel-Rich Layered Transition Metal Oxides: Surface Characterization after Li+/H+-Exchange

With an increasing demand for high-capacity cathode active materials (CAMs) for lithium-ion batteries, nickel-rich layered lithium nickel cobalt manganese oxides (NCMs, LiNixCoyMnzO2, with x+y+z = 1) are the currently favored CAMs [1]. However, a higher nickel content does not only increase the specific capacity of NCMs, but also the reactivity of the CAM surface, which makes the material more prone to surface contaminants [2]. These contaminants consist of lithium salts from excess synthesis precursors [3], but can also be formed during improper storage [4,5]. During battery cycling, these contaminants decompose during the first charge/discharge cycles, leading to excessive gassing [6], decomposition of electrolyte solvents and salts [7], as well as to impedance build-up and capacity fading [8].Since these contaminants are generally soluble in water, CAMs are usually washed after synthesis. Exposure to liquid or gaseous water, however, is accompanied by a Li+/H+-exchange, whereby protons intercalate into the CAM [9]. Within the framework of this study, we examine the kinetics of the Li+/H+-exchange for a Ni-rich NCM831205 (LiNi0.83Co0.12Mn0.05O2). The amount of protons inserted into the CAM upon washing was characterized by different methods, namely acid/base titration, thermogravimetric analysis, X-ray powder diffraction, and prompt-gamma activation analysis [10]. The effect of ion-exchanged protons on the electrochemistry was then investigated for NCM831205 samples with 1.0 and 1.5 mol% H+. Here it was found that protonated NCMs can be cycled fully reversibly, yet the capacity fading increases with increasing proton concentration while the rate capability decreases [11].In this work, we now particularly focus on the surface and the bulk of differently washed NCM samples by using X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS), respectively. It will be demonstrated that protons intercalate into the near-surface region of the NCM particles, as had only been hypothesized so far [9]. Moreover, the protonated NCM material shows a slightly different Ni-coordination, while maintaining its layered structure. The surface thickness of the protonated layer is determined by quantitative XPS analysis: for example, washing at room temperature for 60 min at a water/CAM mass ratio of 5/1 leads to an approximately 2.5 nm thick protonated surface layer. Lastly, temperature induced phase changes of the protonated surface region are characterized by in-situ by XPS during heating of the sample in vacuum. The data are then correlated with previous results from powder X-ray diffraction. Reference s [1] U. Kim. D. Jun, K. Park, Q. Zhang, P. Kaghazchi, D. Aurbach, D. Major, G. Goobes, M. Dixit, N. Leifer, C. Wang, P. Yan, K. Kim, C. Yoon and Y. Sun, Energy Environ. Sci. 11 1271-1279 (2018).[2] W. Li, E. M. Erickson and A. Manthiram, Nature Energy 5 26 (2020).[3] H.-J. Noh, S. Youn, C.S. Yoon and Y.-K. Sun, J. Power Sources 233 121 (2013).[4]J. Sicklinger, M. Metzger, H. Beyer, D. Pritzl and H.A. Gasteiger,J. Electrochem. Soc. 166 (12) A2322 (2019).[5] L. Hartmann, D. Pritzl, H. Beyer and H.A. Gasteiger, J. Electrochem. Soc. 168 070507 (2021).[6] S. Renfrew and B.D. McCloskey, J. Am. Chem. Soc. 139 17853 (2017).[7] M. Metzger, B. Strehle, S. Solchenbach and H.A. Gasteiger, J. Electrochem. Soc. 163 (7) A1219 (2016).[8] R. Jung, R. Morasch, P. Karayaylali, K. Phillips, F. Maglia, C. Stinner, Y. Shao-Horn and H.A. Gasteiger, J. Electrochem. Soc. 165 (2) A132 (2018).[9] D. Pritzl, T. Teufl, A.T.S. Freiberg, B. Strehle, J. Sicklinger, H. Sommer, P. Hartmann and H.A. Gasteiger, J. Electrochem. Soc. 166 (16) A4056 (2019).[10] S. Oswald, R. Wilhelm, T. Kratky, G. Kieslich, L. Szentmiklósi, B. Maróti, I. Harsányi, M. Piana, S. Günther and H.A. Gasteiger, manuscript in preparation. [11] R. Wilhelm, S. Oswald and H.A. Gasteiger, manuscript in preparation. Acknowledgement This work is financially supported by the German Federal Ministry of Education and Research (BMBF) within the project AQua-POp (grant number 03XP0329B) as well as by the BASF SE Network on Electrochemistry and Battery Research.

Determination of boron in borated concrete by means of a simplified prompt gamma activation analysis at the HOTNES facility

Determination of boron in borated concrete by means of a simplified prompt gamma activation analysis at the HOTNES facility

Effects of natural leaching on electronic properties of common lithium manganese oxide LiMn2O4

The effects of degradation and possible leaching of lithium in the natural conditions were tested by subjecting LiMn2O4 to 3-month degradation in an open air environment. The starting material was characterized structurally using X-ray (XRD) and neutron (NPD) powder diffraction and found to crystallize in the nominal Fd-3m space group. The initial chemical composition was verified using X-ray photoelectron spectroscopy (XPS), electron microscopy (EDS) and neutron prompt gamma activation analysis (PGAA). The effects of degradation were studied by reinvestigating the samples using XRD, XPS and X-ray absorption (XAS). The studies did not find any chemical shift of manganese caused by the removal of Li or any statistically significant degradation of the starting composition suggesting that the spinel cathode material is resistant to possible Li removal due to medium term natural exposure.

Analysis of mixture samples of uranium dioxide and boron compounds by using thermal neutron prompt gamma activation analysis

Analysis of mixture samples of uranium dioxide and boron compounds by using thermal neutron prompt gamma activation analysis

PyEGAF: An open-source Python library for the Evaluated Gamma-ray Activation File

The Evaluated Gamma-ray Activation File (EGAF) is one of the most comprehensive resources for thermal neutron-capture data. This database contains data from prompt gamma activation analysis measurements carried out in a consistent manner using the same experimental configuration at the Budapest Research Reactor for 245 isotopes. Although these valuable datasets have been freely available for many years, one of the drawbacks is the outdated and cryptic Evaluated Nuclear Structure Data File (ENSDF) format that is currently adopted for dissemination, making it difficult for users unfamiliar with the format to access and utilize the data contained therein. Furthermore, the ENSDF format does not readily lend itself to modern computational technologies and a parser is required to interpret the complicated mixed-record format. To help overcome these challenges, we have developed a translator to convert the ENSDF-formatted datasets into an open standard JavaScript Object Notation (JSON) format enabling accessibility to applications using different programming languages running in different environments. To compliment this effort, we have also developed an open-source software package implemented in Python, pyEGAF, that is designed to interact with the JSON data structures for general purpose access, manipulation, and analysis of the neutron-capture γ-ray data in EGAF. The new format, together with the pyEGAF library, greatly enhances access to the wider applications community where EGAF data may be useful or is required.

Wide energy region efficiency calibration study of a prompt gamma activation analysis facility

Wide energy region efficiency calibration study of a prompt gamma activation analysis facility

Improved analytical workflow for prompt gamma activation analysis

The analysis workflow of Prompt gamma activation analysis (PGAA) at the Budapest Neutron Centre’s PGAA and NIPS-NORMA facilities, at the MLZ FRM II PGAA station, and other centers worldwide relied on the use of the Hypermet-PC gamma spectrometry software and the ProSpeRo concentration calculation Excel macro. The sustained interest of our user community amid the reduced availability of multiple large-scale neutron sources worldwide called for more efficient utilization of the operational PGAA facilities. The present paper addresses both measurement and data evaluation bottlenecks of the analysis procedure to achieve higher productivity and superior spectroscopic performance.

A comparison of machine learning methods to classify radioactive elements using prompt-gamma-ray neutron activation data

The detection of illicit radiological materials is critical to establishing a robust second line of defence in nuclear security. Neutron-capture prompt-gamma activation analysis (PGAA) can be used to detect multiple radioactive materials across the entire Periodic Table. However, long detection times and a high rate of false positives pose a significant hindrance in the deployment of PGAA-based systems to identify the presence of illicit substances in nuclear forensics. In the present work, six different machine-learning algorithms were developed to classify radioactive elements based on the PGAA energy spectra. The model performance was evaluated using standard classification metrics and trend curves with an emphasis on comparing the effectiveness of algorithms that are best suited for classifying imbalanced datasets. We analyse the classification performance based on Precision, Recall, F1-score, Specificity, Confusion matrix, ROC-AUC curves, and Geometric Mean Score (GMS) measures. The tree-based algorithms (Decision Trees, Random Forest and AdaBoost) have consistently outperformed Support Vector Machine and K-Nearest Neighbours. Based on the results presented, AdaBoost is the preferred classifier to analyse data containing PGAA spectral information due to the high recall and minimal false negatives reported in the minority class.

Hungarian Fine-to-Coarse Aggregate, a Possible Constituent of Near-Vessel Structural Concrete of Nuclear Power Plants.

Significant gravel mines, representative of four regions of Hungary (northeast, central, northwest, and southwest) were systematically sampled to characterize their sand and pebbles as potential constituents of nuclear-grade concrete. The samples were analysed for their elemental compositions as a function of the mining locality and grain size, using two complementary neutron-based analytical techniques, prompt gamma activation analysis (PGAA) and neutron activation analysis (NAA). The combined analysis resulted in reliable mass fractions for over thirty elements that could be used to assess the radiation shielding and activation properties of the resulting concrete, essential in nuclear applications, by means of computer simulations. The studied aggregates are proven to be appropriate constituents for biological shielding at radiological centres, NPPs, and at nuclear research installations, even in mixed neutron/gamma radiation fields. The elemental compositions also revealed geochemical differences between the sedimentologically different regions.

Quantitative, non-destructive elemental composition analysis of 3D-structured samples

By combining the non-destructive position-sensitive prompt-gamma activation analysis, neutron computed tomography, and Monte Carlo computer simulations, quantitative matrix-effect correction of a structured, multi-component sample has been achieved.

Prompt gamma activation analysis as a means for quantitative, non-destructive, non-invasive measurement of mercury in steel from oil and gas operations

Prompt Gamma Neutron Activation Analysis (PGAA or PGNAA) is a non-destructive elemental analysis method potentially applicable for the non-invasive measurement of wall-bound mercury (Hg) deposited at trace levels on the process wetted surface of steel pipe and vessels in oil and gas production and processing. Total wall-bound mercury, on 17 mercury-impacted steel coupon samples was measured by two non-destructive methods: PGAA and XRF (X-ray Fluorescence spectroscopy). Following the non-destructive measurement methods, the samples were digested and analyzed by an Atomic Fluorescence Spectroscopy method based on the principles of EPA 1631 method (Acid Digest-AFS), generally considered state of the art for accurate mercury in steel measurements. PGAA and XRF results were compared to those from the modified EPA 1631 method. Comparative analysis of the results indicated that the PGAA measurements exhibited a trend relatively like that of the acid digest-AFS method measurements. Measurement accuracy, as determined by comparison to a “standard method” (Modified EPA 1631) was not yet adequate for quantitative measurement. However, the consistency in the tracking of the PGAA results with results from the “standard method” along with derivation of a self-attenuation correction factor suggests the potential for improved accuracy and correlation. Details of the intercomparison are provided herein.

Measurement of prompt gamma production from neutron capture on manganese

Prompt gamma radiation is an important part of radiation fields with neutrons. Its good description is vital for precise predictions in void swelling issues because it is a contributor in gamma heating effect. The energy of prompt gamma rays is unique for each nuclide, thus can be used as its signature. Prompt gamma activation analysis is a technique using these gammas in nuclide identification. Despite the prompt gamma importance, current nuclear data libraries describe its origins very inaccurately. Measurement of gamma leakage spectrum of manganese bath with 252Cf neutron source was performed using well-defined HPGe detector with high-density polyethylene shielding and stilbene scintillator. Stilbene measured gamma/neutron spectrum was separated by a Pulse Shape Discrimination method. MCNP6.2 simulation of the experiment was performed with ENDF/B-VIII.0 and JEFF-3.3 libraries for neutrons (and gamma production from neutron interactions) and MCPLIB04 library for photons. Analysis of results revealed that ENDF/B-VIII.0 and JEFF-3.3 description of prompt gamma radiation production is significantly discrepant. INDEN updated data for gamma production on 55Mn was tested as well and show significant improvement compared to original ENDF/B-VIII.0 data. Nevertheless, significant discrepancies up to 50% were still observed. An alternative approach using prompt gamma production tables provided by IAEA was tested as well. Its results are basically in agreement with the calculation using INDEN updated 55Mn data.

Position-Sensitive Bulk and Surface Element Analysis of Decorated Porcelain Artifacts.

Non-destructive characterization of decorated porcelain artifacts requires the joint use of surface-analytical methods for the decorative surface pattern and methods of high penetration depth for bulk-representative chemical composition. In this research, we used position-sensitive X-ray Fluorescence Spectrometry (XRF) and Prompt-gamma activation analysis (PGAA) for these purposes, assisted by 3D structured-light optical scanning and dual-energy X-ray radiography. The proper combination of the near-surface and bulk element composition data can shed light on raw material use and manufacturing technology of ceramics.

Determination of nuclear graphite impurities by prompt gamma activation analysis to support decommissioning operations

Elemental composition of non-irradiated nuclear grade graphite was determined by Prompt Gamma Activation Analysis (PGAA) to quantitively assess some neutron activation precursors. The knowledge of these data is paramount for an accurate radiological characterization of the material before decommissioning of graphite-moderated nuclear reactors. Bulk results of most of the nuclides were consistent with benchmark Inductively Coupled Plasma–Mass Spectrometry (ICP-MS) and literature data. In the case of 14N and 35Cl, depth distribution profiles were observed and quantified for the first time. These outcomes could shine a light on 14C and 36Cl depth distribution profiles and fractional release during leaching experiments.

Applicability of prompt-gamma activation analysis to determine elemental compositions of silicate-based cultural heritage objects and their raw materials

• PGAA is discussed as a tool for heritage objects made of rocks & glass. • The reliability of PGAA is studied via measurements of international SRMs. • Detection limits are compared to the expected ranges of the chemical elements. • H, B and Cl, difficult to analyse with other methods, are separately discussed. Prompt-gamma activation analysis (PGAA) proved to be a very effective non-invasive tool in Heritage Science, applicable to study the bulk-representative elemental composition of a wide range of objects and their raw materials. In this study, we give an overview of the potentials and limitations of the method in the analysis of silicate-based materials. Using appropriate standard reference materials (SRMs), we have investigated the analysis workflow and the individual cases of discriminating elements that are relevant to Heritage Science and routinely measured at the Budapest PGAA laboratory. Geological SRMs representing the raw materials of stone tool manufacturing or historical architecture, as well as glass SRMs, have been studied. With this work, we aim to corroborate the position of PGAA, as an indispensable part of the Heritage Science toolkit. Applicability of prompt-gamma activation analysis to determine elemental compositions of silicate-based cultural heritage objects and their raw materials

Comprehensive study of 12th century wall painting fragments from the St. George Cathedral of the Yuryev Monastery in Veliky Novgorod (Russia) using complementary physico-chemical methods

A total of 7 complementary methods have been applied to investigate unique pre-Mongolian 12th century wall paintings from the St. George Cathedral of the Yuriev Monastery in Veliky Novgorod, Russia. Both archaeological samples from the main space of the Cathedral and fragments in situ in the stairs tower of the Cathedral were studied. For the first time in Russia, sensitive neutron methods were used to study the elemental composition of pigments and plasters—neutron activation analysis and prompt gamma activation analysis. This research made it possible to determine elemental and mineral composition of the pigments and plasters used during creation of wall paintings; identify the technique of paintings; make assumptions about the different time of the paintings creation in the main space of the Cathedral and in its stairs tower; as well as reconstruct the presumable original view of the painting of the St. George figure. The discovery of the expensive lazurite pigment attested to the high status of the ktetor of the Cathedral’s murals. The obtained data were compared with Byzantine and Italian paintings of the same period churches.

Shedding Light on Roman Glass Consumption on the Western Coast of the Black Sea.

The chemical composition of 48 glass finds from Histria and Tomis, Romania, chiefly dated to the 1st–4th c. AD, was determined using prompt gamma activation analysis (PGAA) at the Budapest Neutron Centre (BNC). Most fragments have composition typical for the Roman naturally colored blue-green-yellow (RNCBGY) glass; Mn-colorless, Sb-colorless, and Sb–Mn colorless glass finds were evidenced, too. Several Foy Série 2.1 and Foy Série 3.2 glass fragments, as well as an HIMT and a plant ash glass sample, were identified in the studied assemblage. The archaeological evidence, the glass working waste items, and the samples with compositional patterns suggestive of recycling are proofs of the secondary glass working activities at Tomis during the Early Roman Empire period.