Particle-induced Gamma-ray Emission Research Articles

Ion Beam-Induced Luminescence (IBIL) for Studying Manufacturing Conditions in Ceramics: An Application to Ceramic Body Tiles.

The first experimental results obtained by the ion beam-induced luminescence technique from the ceramic bodies of ancient tiles are reported in this work. The photon emission from the ceramic bodies is related to the starting minerals and the manufacturing conditions, particularly the firing temperature and cooling processes. Moreover, the results indicate that this non-destructive technique, performed under a helium-rich atmosphere instead of an in-vacuum setup and with acquisition times of only a few seconds, presents a promising alternative to traditional, often destructive, compositional characterisation methods. Additionally, by adding other ion beam-based techniques such as PIXE (Particle-Induced X-ray Emission) and PIGE (Particle-Induced Gamma-ray Emission), compositional information from light elements such as Na can also be inferred, helping to also identify the raw materials used.

Oxygen vacancy sensitized energy transfer and tunable emission in Li+ codoped CaWO4:Bi3+

In the present study, Li+ codoped CaWO4:2 % Bi3+ was synthesized by solid state reaction. The synthesized luminescent materials were characterized using x-ray diffraction (XRD), particle induced gamma-ray emission (PIGE), positron annihilation lifetime spectroscopy (PALS) and time resolved photoluminescence (TRPL). Photoluminescence emission studies showed that Lithium co-doping aids in the energy transfer processes and improves emission significantly. This study also shows that emission is tunable via careful choice of excitation scheme and Li+ sensitization to tune the energy transfer from WO42- to Bi3+. Through PALS, it was unequivocally proved that Li+codoping is not charge compensating for the created cation vacancies and improved emission with Li+ codoping is due to sensitization by oxygen vacancies.

Elemental profiling of agricultural soil in Hoshiarpur utilizing analytical techniques.

Our study aimed to assess the soil quality in Punjab's Hoshiarpur district through a meticulous analysis of nutrient and elemental composition. Using a variety of analytical techniques, including Neutron Activation Analysis (NAA), external Particle-induced Gamma-ray Emission (PIGE) an Ion beam analysis Technique, and energy-dispersive X-ray fluorescence (ED-XRF), we delved into soil characterization for 22 agricultural soil samples in the Punjab region. Within the NAA framework, utilizing the Pneumatic Carrier Facility and the self-serve facility at Dhruva reactor in Mumbai, a brief 1-min irradiation procedure identified pivotal elements-Na, Mg, V, Al, Mn, and K. Conversely, an extended neutron irradiation process of approximately 4h within the self-serve facility enabled the estimation of nearly 12 elements, including Rare Earth Elements (REEs), Transition elements, and other significant elements. The external PIGE technique quantified low Z elements (Na, Mg, Al, and Si), contributing to our analytical arsenal. Rigorously validating both NAA and PIGE methodologies, we compared results meticulously against established geological standard reference materials-specifically USGS RGM-1 and USGS AGV-1.Instrumental in elemental analysis, ED-XRF spectroscopy fortified our investigative endeavors by quick assessment of ten crucial elements. The elemental analysis revealed notable accumulations of Mn and Zn in the soil, surpassing the suggested permissible limits, whereas Co, Cr, and Pb were found to be within the recommended thresholds set by WHO/UNEP. Beyond elemental profiling, our study extended to estimate the accumulation levels of various elements utilizing ecological risk factors such as Contamination Factor, Potential Ecological Risk Index, Pollution Load Index, and Geoaccumulation Factor. Our findings highlighted significant accumulation of REEs including La, Sm and Yb.. This evaluation sheds new light on the interplay between soil composition and environmental health, emphasizing the need for advanced accessible agricultural technologies to prevent and forecast contaminant discharge in arable soil. This commitment aligns with our broader goal of advancing sustainable practices in soil management.

Effect of Microstructure on Oxidation and Micro-mechanical Behavior of Arc Consolidated Mo-Ti-Si-(B) Alloys

AbstractThe present study deals with the development and characterization of Mo-35Ti-10Si and Mo-35Ti-10Si-2B (wt.%) alloy for ultra-high temperature applications beyond the temperature limit of existing super alloys. The microstructural characterization using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron back scattered diffraction (EBSD), x-ray diffraction (XRD) revealed that the Mo-35Ti-10Si-2B alloy was consisted of three phases, namely, (Mo, Ti)ss, (Mo, Ti)5SiB2 and (Ti, Mo)5Si3; whereas, Mo-35Ti-10Si alloy was found to be consisting of (Mo, Ti)ss, and (Mo,Ti)3Si phases. Since quantification of boron is difficult by EDS, Particle Induced Gamma-ray Emission (PIGE), a nuclear reaction analysis technique was used for chemical composition analysis of boron. The oxidation behavior of the Mo-35Ti-10Si-2B alloy in the temperature regime of 825-1250 °C was studied in detail and compared with boron-free Mo-35Ti-10Si alloy. Mo-35Ti-10Si-2B alloy exhibited superior oxidation behavior at intermediate temperatures of 825 °C, and excellent oxidation resistance at higher temperatures between 1000 and 1250 °C due to the formation of the protective borosilica and double oxide layers (TiO2 and duplex borosilica-TiO2), respectively. High-temperature oxidation mechanisms were discussed using detailed microstructural cross section analysis of the oxidized alloy samples. The micro-mechanical behavior of constitutive phases of the Mo-35Ti-10Si-2B alloy were studied by microhardness, nano-indentation and micropillar compression testing. The micropillar compression of (Mo, Ti)ss phase showed fairly ductile behavior with the evidence of activation of dislocation in the form of slip lines revealed through the post-deformation fractography. Deformation studies of (Mo, Ti)5SiB2 and (Ti, Mo)5Si3 phases were also carried out which showed large strain bursts indicating possibility of activation of dislocation activities even at room temperatures imparting low level of ductility.

Use of Particle Induced X-Ray Emission (PIXE), Particle Induced Gamma–Ray Emission (PIGE), Energy Dispersive X-Ray Analysis (EDXRF) for Detecting Trace Elements in Soil Sample

This review paper provides a comprehensive overview of trace element analysis utilizing ion-atom interaction techniques, focusing on the principles, applications, and recent advancements in the field. Ion- atom interaction techniques, including Particle Induced X- Ray Emission (PIXE), Particle Induced Gamma–Ray Emission (PIGE), Energy Dispersive X-Ray Analysis (EDXRF), Rutherford backscattering spectroscopy (RBS), and ion beam analysis (IBA), offer unique capabilities for trace element analysis with high sensitivity and minimal sample preparation requirements. The paper begins by discussing the fundamental principles underlying ion-atom interaction techniques, such as the interaction of energetic ions with matter and the subsequent detection of emitted X-rays or backscattered particles. It explores the various analytical parameters that influence the sensitivity, resolution, and depth profiling capabilities of these techniques. Furthermore, the review highlights the diverse applications of ion-atom interaction techniques in fields such as environmental monitoring, forensic science, biomedical research, and materials science. It showcases how these techniques have been utilized to address specific analytical challenges, such as the detection of trace contaminants in environmental samples or the characterization of thin films and semiconductor materials.

The impact of formalin fixation in the elemental content of tissues: Parametrization up to 48 h

Formalin fixation is a crucial step in the preparation of tissue samples for anatomic pathology studies, however, research showed that prolonged formalin fixation, can alter the elemental composition of tissues with implications for pathology and biomedical research. In this study we aim to assess and parametrize the influence of short-term formalin fixation in tissues.Six sets of human colon tissue samples were exposed to different formalin fixation times, up until 48 h. The elemental content throughout time was compared to the elemental content of the snap-frozen sample of the same tissue that was not exposed to formalin using Energy Dispersive X-ray Fluorescence.Results showed a clear decrease of Cl and K concentration in the tissues solution reaching a plateau between 1 h and 3 h of fixation. Also, there is an uptake of P in the tissue, likely due to the buffered formalin solution, within the first 15 min of fixation. This behaviour was concomitant with an increase of Na determined using Particle Induced gamma-ray emission analysis (PIGE) and Elastic Backscattering Spectroscopy (EBS). The dynamic changes determined in the studied elements demonstrate that a better understanding of the fixation-related mechanisms is in demand as well as optimization of the fixation protocols implemented in anatomic pathology laboratories.

Application of non-destructive analysis methods in TENMAK-PAF

Development of non-destructive analysis systems at the R&D beamline of the Proton Accelerator Facility of the Turkish Energy, Nuclear and Minerals Research Agency (TENMAK-PAF) is described in this work. The proton beam from the cyclotron with energy between 15–30 MeV and current between 0.1 μA–1.2 mA is modified with several components and subsystems to be suitable for the application of non-destructive analysis methods. Certified reference materials (CRM) and samples with different properties were irradiated under vacuum in the irradiation chamber with the new system. Particle Induced X-ray Emission (PIXE) and Particle Induced Gamma ray Emission (PIGE) spectra of these samples were obtained with appropriate radiation detectors and measurement systems. The results of PIXE analyses and X-ray fluorescence (XRF) spectrometry were compared. PIXE and PIGE results are in good agreement with the certified values for the CRMs. This work constitutes the first reported application of non-destructive ion beam analysis methods in TENMAK-PAF and in Türkiye.

Quantification of lithium in hyper-stoichiometric lithium titanate by external (in air) particle induced gamma-ray emission (PIGE) method

Quantification of lithium in hyper-stoichiometric lithium titanate by external (in air) particle induced gamma-ray emission (PIGE) method

Alumino-Silico-thermic synthesis of high purity ferroboron alloy and its characterization

High purity ferroboron (Fe–B) alloy is used as an alloying agent for making special grades of steels, Nd-Fe-B magnets etc. In this study, alumino-silico-thermic co-reduction of Fe2O3 and B2O3 was attempted to prepare high purity Fe–B. Extensive differential thermal analysis (DTA) studies were carried out to understand the reduction behaviour of Fe2O3 and B2O3 by Al and Si. DTA exothermic peaks indicated three step reduction of Fe2O3 (Fe2O3→Fe3O4→FeO→Fe) when reacted with Al and Si separately. B2O3–Si system did not show exothermic peaks while heating indicating sluggish or no reduction, however, B2O3–Al DTA peaks indicated two step reduction behaviour. Differential thermal analysis of Fe2O3–B2O3–Al–Si indicated completion of reduction of oxides, and formation of different intermediate phases. Specially designed reduction reactors were used to produce ferroboron alloy in bulk quantities. Thermal analysis results suggested that the formation of aluminium and silicon borides could be avoided using sub-stoichiometric amount of Al and Si, which was further confirmed from the bulk thermit product. Si acted as reducing agent as well as forming low melting slag comprising of Al(Si)–B–O type oxides. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and Particle Induced Gamma-ray Emission (PIGE) analysis confirmed the presence of 12 wt% boron in the alloy product with lower content (<1 %) of impurity elements like Al and Si. The relationship between the chemical homogeneity with the thermit process parameters was established. Microstructure and mechanical properties confirmed the formation of Fe2B and FeB phase in the thermit alloy.

Development of an external PIGE method using nitrogen from atmospheric air as external beam current normalizer and its application to nondestructive quantification of total boron mass fraction in boron containing neutron absorbers

Beam current monitoring and normalization is a very important task in ion beam analysis experiments. Compared to current monitoring by conventional method, in situ or external beam current normalization is attractive in Particle Induced Gamma-ray Emission (PIGE), which involves simultaneous measurement of prompt gamma rays of analyte of interest and current normalizing element. In the present work, an external (in air) PIGE method has been standardized for quantification of low Z elements using nitrogen from atmospheric air as external current normalizer, in which 2313 keV of 14N(p,p’γ)14N is measured. It provides truly nondestructive and greener quantification method for low Z elements by external PIGE. The method was standardized by quantifying total boron mass fractions in ceramic/refractory boron-based samples using low energy proton beam from tandem accelerator. The samples were irradiated with 3.75 MeV proton beam and prompt gamma rays of analyte at 429, 718 and 2125 keV of 10B(p,αγ)7Be, 10B(p,p’γ)10B and 11B(p,p’γ)11B, respectively, and external current normalizers at 136 and 2313 keV were measured simultaneously using high resolution HPGe detector system. The obtained results were compared with external PIGE method using tantalum as external current normalizer, where 136 keV of 181Ta(p,p’γ)181Ta from beam exit window material (Ta) was used for current normalization. The developed method is found to be simple, rapid, convenient, reproducible, truly nondestructive and more economical as no additional beam monitoring instruments are required and it is especially advantageous for direct quantitative analysis of ‘as received’ samples.

External Beam IBA Measurements for Cultural Heritage

Ion beam analysis (IBA) methods refer to a set of analytical techniques based on the interactions of energetic ions, produced by a particle accelerator, with matter. The result of such interactions is the emission of characteristic radiation, X and gamma rays, and charged particles, which, upon detection, provide valuable information on the absolute concentration and depth distribution of the elements in the bombarded material. Moreover, IBA techniques can be performed while maintaining the object to be investigated at atmospheric pressure, without placing it in vacuum, in an analysis chamber, with the impinging ion beam extracted from the in-vacuum beamline of the accelerator, avoiding the need of invasive sampling and greatly easing the object positioning, thus allowing precious and big or large artefacts to be studied. This feature has opened the way for applications of IBA techniques for compositional analysis in cultural heritage studies, providing detailed and complete information about elemental compositions and depth distributions of analysed materials that are otherwise difficult or impossible for other analytical techniques. In this paper, the basic principles of the main IBA techniques applied to cultural heritage, namely, particle induced X-ray emission (PIXE), particle induced Gamma-ray emission (PIGE), and Rutherford or elastic backscattering spectrometry (RBS/EBS), will be recalled, and specific and practical details on how these techniques can be used for analysing cultural heritage objects with external beam set-ups will be provided.

Toward Developing Techniques─Agnostic Machine Learning Classification Models for Forensically Relevant Glass Fragments.

Glass fragments found in crime scenes may constitute important forensic evidence when properly analyzed, for example, to determine their origin. This analysis could be greatly helped by having a large and diverse database of glass fragments and by using it for constructing reliable machine learning (ML)-based glass classification models. Ideally, the samples that make up this database should be analyzed by a single accurate and standardized analytical technique. However, due to differences in equipment across laboratories, this is not feasible. With this in mind, in this work, we investigated if and how measurement performed at different laboratories on the same set of glass fragments could be combined in the context of ML. First, we demonstrated that elemental analysis methods such as particle-induced X-ray emission (PIXE), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM-EDS), particle-induced Gamma-ray emission (PIGE), instrumental neutron activation analysis (INAA), and prompt Gamma-ray neutron activation analysis (PGAA) could each produce lab-specific ML-based classification models. Next, we determined rules for the successful combinations of data from different laboratories and techniques and demonstrated that when followed, they give rise to improved models, and conversely, poor combinations will lead to poor-performing models. Thus, the combination of PIXE and LA-ICP-MS improves the performances by ∼10-15%, while combining PGAA with other techniques provides poorer performances in comparison with the lab-specific models. Finally, we demonstrated that the poor performances of the SEM-EDS technique, still in use by law enforcement agencies, could be greatly improved by replacing SEM-EDS measurements for Fe and Ca by PIXE measurements for these elements. These findings suggest a process whereby forensic laboratories using different elemental analysis techniques could upload their data into a unified database and get reliable classification based on lab-agnostic models. This in turn brings us closer to a more exhaustive extraction of information from glass fragment evidence and furthermore may form the basis for international-wide collaboration between law enforcement agencies.

Implication of nuclear analytical techniques for the assessment of coal quality in terms of ash content

ABSTRACT The manuscript deals with the utilization of Neutron Activation Analysis (NAA), external (in air) Particle Induced Gamma-ray Emission (PIGE) and X-Ray Fluorescence (XRF) for comprehensive characterization of Indian coal in order to evaluate their quality in terms of ash contents. NAA was used involving short irradiation at Pneumatic Carrier Facility (PCF) at Dhruva reactor, India, for determination of Na, Mg, Al and K; whereas long irradiation at Apsara-U reactor was used for estimation of Fe and Ca. External PIGE was applied for quantification of low Z elements (Na, Mg, Al and Si). Method was validated using coal-based standard reference materials: NIST 1635a and 1633c. Comparative evaluation was also carried out using Energy Dispersive X-Ray Fluorescence (EDXRF) spectroscopy. Total concentration of Na, Mg, Al, Si, K, Ca, Ti and Fe oxides has been used as markers for identifying the quality of coal in terms of coal ash contents. Elements such as Sc, Cr, Co, Zn, Se, Cs, Ce, Sm, Hf, U and Th were determined at trace level using conventional NAA techniques after long irradiation at Apsara-U reactor. The coal with higher ash content was found to contain high concentration of trace elements and the better quality coal contains lower concentration of trace elements.

Nuclear techniques in forensic toxicology

Illegal trades carried out by criminal organisations are a major threat to health and security worldwide. Criminal organisations are trading both drugs of abuse and illegal pharmaceutical products and supplements. The aim of our research is to show how nuclear techniques can support the protection of public health and the fight against illegal trades of interest for forensic toxicology, providing key analytical information. Specimens of Cannabis sativa L. were analysed by instrumental neutron activation analysis for Al, As, Br, Ca, Cd, Co, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc, Sm, Sr, V, and Zn. Illegal pharmaceutical products containing sildenafil and preparations containing oxandrolone (a doping agent) were analysed by accelerator-based nuclear analytical techniques, such as Ion Beam Analysis (IBA), for elemental analysis, and by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS) and Gas Chromatography coupled to mass spectrometry (GC-MS) for organic analysis. IBA analysis by PIXE (Particle-Induced X-ray Emission), PIGE (Particle-Induced Gamma-ray Emission) and EBS (Elastic Backscattering Spectrometry) were carried out using an accelerated proton beam extracted in air with no sample preparation. Statistical evaluation was carried out by hierarchical cluster analysis and principal component analysis. Several elements (F, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Br and Sr) were identified in the illegal products containing sildenafil (6 specimens) or oxandrolone (6 specimens) by PIXE, allowing their quantitative elemental characterisation. Secondary ion mass spectrometry using primary ions with energies in the range of several MeV (MeV-SIMS) provided analysis of organic active compounds and organic impurities. The traditional approach based on chromatography coupled to mass spectrometry provided complementary organic analysis. Authentic Viagra was also analysed. Cluster analysis of the results from 63 specimens was able to group the Cannabis specimens into their known or reported growing regions with a high degree of accuracy. Principal component analysis was also able to elucidate some of the underlying geochemical factors that could explain the clustering. The IBA results showed that a simple criterion suggested in a previous work to identify authentic Viagra is valid also for the analysis carried out in different laboratories (LABEC accelerator of the INFN Division of Florence and IIL in Brazil). Nuclear techniques showed to be effective to support the protection of public health and the fight against illegal trades of interest for forensic toxicology, providing key analytical information inaccessible with traditional analysis by LC-HRMS and GC-MS). Timely analytical results are needed to provide early warning for public health. Nuclear techniques should be further studied to allow a global inter-laboratory classification system of drugs of abuse, doping products and illegal pharmaceutical products. The elemental characterisations provided is complementary to the organic information obtained by the traditional analytical approach based on chromatography coupled to mass spectrometry. Global databases could allow inferring about common characteristics of illegal products such as provenience of bulk materials, site of production etc., providing key forensic information to support the fight against illegal trades.

Boron Isotopic Ratio (δ11B) Measurements in Boron Carbide (B4C): Benchmarking Between SF-ICP-MS and PIGE Techniques

The results of comparing the analytical capabilities of Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) and Particle Induced Gamma-ray Emission (PIGE) methods for determining the 11B/10B isotope ratio in boron carbide samples (B4C) are presented. The following nuclear reactions excited by protons on the stable boron isotopes are considered: 10B(p,aγ)7Be, 10B(p,pγ)7Be and 11B(p,γ)12C. The optimum proton energy range was determined to be within 550 to 600 keV, while the energies of the induced gamma-radiation that can be used for quantitative estimation of the boron isotopes were 429 keV and 4439 keV for the isotopes 10B and 11B, respectively. Considering the uncertainties of measurements, the data for the 11B/10B isotope ratios, measured by the SF‑ICP‑MS and PIGE methods, are found to correlate with each other; yet they are characterized by a systematic bias. The uncertainty of measurements by the PIGE method was somewhat higher in comparison with SF-ICP-MS, and ranged from ± 4.1 % to ± 4.3 %, and from ± 1.1 % to ± 3.5 %, respectively.

A forensic procedure based on GC–MS, HPLC-HRMS and IBA to analyse products containing sildenafil or the doping agent oxandrolone

The market of falsified or sub-standard medical products is a global scale phenomenon. This issue affects a wide range of medications, including life-saving medical products. In high-income countries the most falsified products are those defined “lifestyle”, which include foremost anabolic steroids and phosphodiesterase 5 inhibitors. The spread of these products in the last years has been possible also because of their online purchase, since they can be bought anonymously and without any medical supervision or prescription. Their use can pose a serious threat for public health, especially because often are manufactured without adherence to quality standards. This leads to final products containing active ingredients different from those declared, at the wrong or unknown dose and contaminated with metals, synthesis by-products and other chemical substances. In this work, we present results on characterisation of illegal pharmaceutical products and doping agents by combining different techniques: chromatography coupled to mass spectrometry for organic analysis and accelerator-based nuclear analytical techniques, such as ion beam analysis (IBA), for elemental analysis. Three IBA techniques, namely PIXE (particle induced X-ray emission), PIGE (particle induced gamma-ray emission) and EBS (elastic backscattering spectrometry) were used in external beam mode to provide an elemental characterisation of the as-is material, placed simply in front of the proton beam, thus avoiding the need of preparing them with pre-analytical steps and greatly enhancing the measurement throughput. Several elements (F, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Br and Sr) were identified in the analysed products. External beam IBA measurements provided the quantitative elemental characterisation of the illegal pharmaceutical products and doping agents under study, complementary to the organic analysis results by chromatography and mass spectrometry thus allowing a rapid (a few minutes) and non-destructive direct assessment of the material for forensic purposes. For the first time IBA results from doping products are reported and further analysis by IBA involving two different accelerator laboratories (one in Italy and one in Brazil) allowed the comparison of results obtained on the same pharmaceutical product. Starting from the results obtained in our study, the actualisation of new research plans should be evaluated, which could lay the foundation for a classification system of illegal pharmaceutical products, doping products. and other substances, based on chromatography, mass spectrometry and IBA measurements; this could allow drawing inferences about the common characteristics of these substances, e.g. provenience of bulk materials, site of production etc. With this purpose, results obtained from two samples of the same pharmaceutical product by IBA in two different accelerator laboratories (one in Italy and one in Brazil) are compared.

Utilization of accelerator and reactor based nuclear analytical techniques for chemical characterization of automobile windshield glass samples and potential of statistical analyses using trace elements towards glass forensics

Glass forensics is an important area in forensic crime investigations, wherein glass origin or source finding is necessary mainly through chemical composition. In the present work, Nuclear Analytical Techniques namely external (in air) Particle Induced Gamma-ray Emission (PIGE) and Instrumental Neutron Activation Analysis (INAA) were utilized for complete chemical characterization of twenty-five “as received” windshield glass samples of six car manufactures. Concentrations of four major elements (Si, Na, Mg and Al) by PIGE using proton beam and nineteen elements including sixteen trace elements by INAA using research reactor neutrons were determined. Both the methods were validated by analysing matrix matched glass certified (standard) reference materials. Trace elemental concentrations including rare earth elements (REEs) and ternary plot using concentrations of major, transition elements and REEs were utilized to obtain preliminary grouping of the analyzed glass samples. Statistical tools namely K-mean, Cluster Analysis and Principal Component Analysis (PCA) using trace elemental concentrations were utilized for grouping studies, important for forensic applications. Among these statistical analysis techniques, PCA results confirmed that windshield glasses from six manufactures clearly belong to six different groups.

Development of an innovative external (in air) Particle Induced Gamma-ray Emission method for rapid non-destructive determination of isotopic composition of boron in “As received” boron based ceramic neutron absorbers

Boron is an important element in nuclear reactor technology due to its high neutron absorption cross section of 10B isotope. Isotopic composition of B (IC, 10B/11B atom ratio) determination in finished neutron absorbers is a necessity under chemical quality control (CQC). We report an innovative greener method for rapid and non-destructive approach of isotopic composition determination of B in “as received” boron based ceramic neutron absorbers including boron carbides and hexa-borides by external (in air) Particle Induced Gamma-ray Emission (PIGE) using 3.5 MeV proton beam. It involves irradiation of “as received” powder samples wrapped in a thin Mylar film and measurement of prompt gamma rays at 429, 718 and 2125 keV from 10B(p,αγ)7Be, 10B(p,p’γ)10B and 11B(p,p’γ)11B, respectively, using a HPGe detector system. The method was standardized with natural and enriched B4C powders. For validation, the results of isotopic composition obtained from “as received” samples were compared with that obtained from pellet samples using both external and vacuum chamber PIGE methods. IC values obtained for natural to 10B enriched samples (19.8–67 atom % of 10B) are very encouraging with 1–2% and 0.3–0.7% uncertainties from single and replicate sample experiments. The method is truly non-destructive as the samples can be returned back as such after the experiment as they are not radioactive. Compared to existing PIGE method for isotopic composition of B, the developed method keeps promise for wide applications as it is simple, sensitive and rapid and it does not require vacuum, pellet preparation with a binder, exact mass of the sample and beam current measurement.

Investigation of the protective suitability of a dental fluorinated varnish by means of X Ray fluorescence and Raman spectroscopy

Background and aimEvaluating the protective effect in human enamel of a fluorinated varnish after enduring a citric acid erosive challenge. MethodsAn in vitro model was developed considering the intraoral environment, human saliva and acid erosive procedures. The evaluation of the enamel specimens was undertaken through the direct analysis of enamel by means of Raman spectroscopy and Energy Dispersive X Ray Fluorescence (EDXRF). Ten tooth specimens per group were analysed during three stages: 1- before treatment; 2- After varnish (treatment group) or toothpaste (control) application; 3- After citric acid cycle. Additionally, Particle Induced Gamma Ray emission (PIGE) was used to gauge the fluorine uptake by enamel after the application of the varnish (stage 2). Results were presented as mean and standard deviation with ANOVA and Tukey post hoc performed considering a significance level of 0.05. ResultsA significant (p < 0.05) higher Ca levels were detected in treatment group at stage 2 (37.4 ± 0.4 w/w%) and 3 (37.1 ± 0.1) when compared to the control group. After varnish application in treatment group, depolarization ratios were significant lower (p < 0.05) and anisotropy were significant higher (p < 0.05), however no differences were detected in FWHM. ConclusionsThe use of a fluorinated dental varnish suggests a protective effect for human enamel against dental erosion demineralization process which was detectable in an in vitro model.

Optimization of external (in air) particle induced gamma-ray emission (PIGE) methodology for rapid, non-destructive, and simultaneous quantification of fluorine, sodium, and phosphorus in nuclear waste immobilization matrices.

External (in air) PIGE methodology has been optimized for rapid quantification of fluorine, sodium, and phosphorus in fluorapatite waste immobilization matrices for Molten Salt Reactor (MSR). The present methodology addresses the issue of distinguishing hydroxyapatite and fluorapatite phases through XRD patterns. Fluctuations in proton beam current have been monitored by prompt γ-ray from nitrogen (2312 keV) through 14N(p,p'γ)14N nuclear reaction and have successfully been applied as a new method of current normalization, for the first time, in external PIGE method with lower Compton background and negligible spectral interference. The proposed method was also compared with the earlier method of current normalization using 165 keV (181T(p,p'γ)181Ta) from the Tantalum window used for obtaining "in air" beam. For the fluctuation of beam current within 5-10 nA, nitrogen from air can be used as an effective current normalizer. Moreover, the uncertainty (within ±3%) was also improved in the present method of current normalization. Fluorine can be estimated from trace to major concentrations using 197 keV (19F(p,p'γ)19F) γ-ray with highest sensitivity as compared to other prompt γ-rays (110 keV and 1236 keV). The matrix effect in PIGE was also eliminated by diluting the sample in cellulose. The method was validated using the synthetic samples (Ca10(PO4)6F2, Na2Eu2Ca6(PO4)6F2, Na1.5Eu1.5Ca7(PO4)6F2, Na1Eu1Ca8(PO4)6F2, Na0.5Eu0.5Ca9(PO4)6F2, and Sr10(PO4)6F2). The results were found to be satisfactory and in good agreement with stoichiometric amounts. Elements such as Na, P, and Ca were determined in the fluorapatite samples using PIGE and EDXRF, respectively, as a part of chemical quality control. Moreover, in external PIGE, 1266 keV γ-ray (31P(p,p'γ)31P) provides more accurate P concentrations in the samples.