PIXE 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.

Evaluation of the Effects of High Silver and Copper Nanoparticle Concentrations on Vaccinium myrtillus L. under Field Conditions.

The extensive development of nanotechnologies has allowed nanoparticles to impact living systems through different pathways. The effect of single exposure to high concentrations of silver and copper nanoparticles (50-200 mg/L) on Vaccinium myrtillus L. under field conditions was investigated. Nanoparticle uptake in different segments of Vaccinium myrtillus L. was assessed by applying inductively coupled plasma-atomic emission spectroscopy and a particle-induced X-ray emission technique. Copper nanoparticles mainly accumulated in the roots and leaves, while silver nanoparticles showed a higher affinity for the roots and berries. The nanoparticles' effects on the pigments and antioxidant activity of the plant's leaves were also evaluated. The possible human health risk associated with the consumption of nanoparticle-contaminated berries was assessed. The results indicated that the consumption of berries contaminated with nanoparticles presented a low risk for human health.

Characterization of mineral composition using PIXE and EXAFS analyses to elucidate the Barium adsorption mechanism

Ningyo-toge is a uranium (U) mine that was operative in Japan. Currently, the mining area retains a dump of mill tailings. Groundwater is contaminated with U ore, and mill tailings might contain radioactive elements, such as U and radium (Ra), which can negatively impact the human body. This study determined the soil composition at the tailings dumping site using particle-induced X-ray emission, scanning electron microscopy, and X-ray diffraction and observed the adsorption structure of barium (Ba), an analog of Ra, using X-ray absorption fine structure analysis. The results revealed the existence of silicate minerals, such as quartz and mica, and metal oxides, such as Fe and Mn, in the soil. Ningyo-toge soil is similar to montmorillonite and bentonite. In particular, it was proposed that the adsorption of Ba on Mn oxide is an inner-sphere complex that immobilizes Ba. These findings will provide valuable information for estimating the behavior of Ra in the environment. The results of this study will be helpful for safety assessment and evaluating the impacts on the surrounding environment.

Baseline measurements in the assessment of ESS-specific radionuclide uptake by crops cultivated in Southern Sweden

The European Spallation Source, ESS, is a neutron research facility under construction in Lund, Southern Sweden. The Facility will produce neutrons by spallation, using a powerful linear accelerator to deliver protons to a tungsten target. In addition to the desired neutron production, a long list of radionuclides will be created as by-products of the nuclear reaction inside the target. The Swedish Radiation Safety Authority has established a list of the most relevant radionuclides, in terms of contribution to the effective dose to ESS workers and the general public, should an accidental release of irradiated target material occur. This list includes radionuclides that are not produced by the nuclear energy industry, in particular 178mHf, 182Ta, 187W, 148Gd and 173Lu. Ongoing research efforts aim to determine the best analytical methods to assess these exotic and often difficult-to-measure radionuclides in environmental samples. This work investigates the potential of X-ray fluorescence and time-of-flight elastic Recoil detection analysis for the assessment of soil samples, and the potential of particle induced X-ray emission for the assessment of crop samples. These techniques require only simple sample preparation steps and no chemical extraction, unlike the conventional environmental monitoring methods such as inductively-coupled plasma mass spectrometry, and show promise as complimentary methods enabling fast sample throughput. This study focuses on the analysis of uncontaminated soil and crops, to provide baseline data, whilst simultaneously assessing the available measurement capabilities. For the X-ray fluorescence system used in this study, the method detection limit for W in soil was determined to be 0.147ppth, and Zr which can be correlated with the migration of Hf was clearly measurable.

Micro PIXE mapping proves a differential distribution and concentration of trace elements in fungal structures of Rhizophagus intraradices

Arbuscular mycorrhizal (AM) fungi can sequester different potentially toxic elements, such as trace elements (TEs), within their structures to alleviate the toxicity for its host plant and themselves. To elucidate the role of AM fungi in TEs immobilization in the rhizosphere of host plants, it is important to know the TEs distribution in AM fungal structures. In the present study, we investigated the distribution and concentration of TEs within extraradical spores and mycelium of the AM fungus Rhizophagus intraradices, collected from the rhizosphere of Senecio bonariensis plants grown in a soil polluted with multiple TEs, by using Particle-Induced X-ray Emission with a micro-focused beam (micro PIXE). This technique enabled the simultaneous micrometric mapping of elements in a sample. The calculated values were compared with those in the polluted substrate, measured by the Wavelength Dispersive X-ray Fluorescence technique. The highest concentrations of Fe, P, Ti, Mn, Cr, Cu and Zn were found in AM fungal spores, where they were accumulated, while extraradical mycelium was enriched in Cu. Finally, we demonstrated that AM fungi can simultaneously accumulate high amounts of different TEs in their structures, thus reducing the toxicity of these elements to its host plant.

Upgrade of the ion beam analysis end-station with the wavelength dispersive X-ray spectrometer for use with the focused MeV ion beams

A novel modular end-station has been developed for use with focused MeV ion beams. It supports analysis of micro-samples using simultaneously several ion beam analysis (IBA) techniques, including wavelength dispersive (WD) and energy dispersive (ED) Particle Induced X-ray Emission (PIXE) spectrometry, Elastic Backscattering Spectrometry (EBS and RBS) and Nuclear Reaction Analysis (NRA). The end-station enables quantitative elemental analysis, including the creation of two-dimensional elemental maps based on the ED-PIXE and EBS/RBS/NRA measurements. The in-house developed wavelength dispersive X-ray (WDX) spectrometer can measure high energy resolution spectra on selected sample micro-regions. In this work the description of the modular end-station is presented, highlighting the features of the WDX spectrometer: i) in the complementary analysis of complex ED X-ray spectra with many overlapping peaks measured simultaneously and ii) in chemical speciation studies. An example is presented to demonstrate the capabilities of the modular system for simultaneous analytical measurements of selected heterogeneous micro-samples.

Elemental Profiling of Common Anti-diabetic Medicinal Plants of Swat and Peshawar Districts of Khyber Pakhtunkhwa (KPK) Province of Pakistan: An Investigation Using PIXE and ICP-OES.

The use of medicinal plants is integral to addressing liver, heart, lung, and other metabolic issues. These plants are rich in vitamins, minerals, flavonoids, and alkaloids, which collectively help in lowering intestinal glucose absorption and increasing insulin secretion by pancreatic tissues. Elemental analysis, encompassing major, minor, and trace elements, was performed on various parts (leaves, roots, and seeds) of 16 anti-diabetic medicinal plants collected from different regions of Swat and Peshawar in Khyber Pakhtunkhwa (KPK), Pakistan. This analysis utilized proton-induced X-ray emission (PIXE) and inductively coupled plasma optical emission spectroscopy (ICP-OES) techniques. Our PIXE and ICP-OES analysis revealed the presence of major (Ca, K, S, P), minor (Si, Cl), and trace (Al, Mn, Fe, Ni, Cu, Zn, Se, Cr, and Sc) elements in various parts (leaves, roots, and seeds) of the 16 anti-diabetic medicinal plants studied. Specifically, elements such as Ca, K, Cr, Cu, Mn, Zn, and Se were detected, all of which are known to contribute in maintaining normal glucose metabolism. Notably, Zn and Se are crucial trace elements for the synthesis, secretion, and action of insulin. Significant Zn concentrations were observed in ten anti-diabetic medicinal plants: Albizia lebbeck (AL), Atropa acuminata (AA), Avena fatua (AF), Citrus medica (CM), Commiphora wightii (CW), Cymbopogon citratus (CC), Daucus carota (DC), Ziziphus mauritiana (FM), Hyoscyamus niger (HN), and Martynia annua (MA), and significant Se concentrations were observed in twelve medicinal plants, i.e., Albizia lebbeck (AL), Allium sativum (AS), Atropa acuminata (AA), Avena fatua (AF), Cannabis sativa (CS), Capparis spinosa (CaS), Commiphora wightii (CW), Cymbopogon citratus (CC), Datura alba (DA), Daucus carota (DC), Ziziphus mauritiana (FM), and Hyoscyamus niger (HN). Our study's elemental analysis using PIXE and ICP-OES on various parts of 16 medicinal plants identified a significant number of useful elements. Elements such as Ca, K, S, P, Al, Si, Cl, Mn, Fe, Ni, Cu, Zn, Se, and Cr were identified and quantified. These findings support the potential use of these plants in managing diabetes and highlight the importance of elemental profiling in understanding their therapeutic properties.

Practices and Rules of 16th Century Genoese Gilding: Exploring Gold Leaf Thickness and Caratage through X-ray and Ion Beam Techniques

This study investigates the practices and rules of Genoese gilding, drawing insights from a 16th-century manuscript containing regulations for gold leaf production. Employing X-ray and ion beam techniques, we quantitatively assess the manuscript’s gold leaf thickness without destructive sampling. Artisanal goldbeater-produced leaves of different thicknesses, applied with a guazzo or mordant technique, served as standards. Further analysis of samples with unknown thickness from the furniture of Palazzo Spinola di Pellicceria in Genoa (Italy) has confirmed the method’s applicability to practical cases. External beam Rutherford backscattering spectrometry (RBS) and particle-induced X-ray emission (PIXE) analyses were carried out using 3 MeV protons at the LABEC accelerator laboratory in Florence. A linear relationship between Gold Lα peak yield and leaf thickness, as measured by RBS, has been established for optimal calibration of portable or hand-held X-Ray fluorescence (XRF) instrumentation for in situ measurements. Moreover, the caratage of the gold foil preserved in the manuscript has been assessed.

Application of pollution indices to determine pollution intensities in the groundwater of Gopalganj (south-central part), Bangladesh

Heavy metals (HMs) contamination in groundwater (GW) is a serious concern due to growing urbanization, industrialization, and contemporary farming practices. The GW in the Gopalganj district of Bangladesh is particularly vulnerable to this pollution. The purpose of this research is to evaluate the pollution intensities in shallow groundwater (SGW) using multiple pollution indices, including Heavy-metal Pollution Index (HPI), Heavy-metal Evaluation Index (HEI), Degree of Contamination (Cd), Synthetic Pollution Index (SPI), Metal Index (MI), and Ecological Risk Index (ERI). As a consequence, the concentrations of arsenic (As), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) were measured using the Particle-induced X-ray Emission (PIXE) method. Roughly 30.58% of the samples exceeded the acceptable level of As. The concentration of the other two metals also excedded, namely Fe and Mn, were 99.42% and 48.00%, respectively. According to HPI, 85.29% of the samples were unsuitable for drinking, 10.59% were questionable, and the rest 4.12% of the samples were suitable for drinking purposes. The HEI depicted that 82.94% of SGW were high pollution, 14.12% were medium pollution, and the remaining 2.94% were low pollution status. In addition, the Cd and MI results exhibited that the majority of the samples were highly contaminated. The SPI values showed that 54.71% of samples were unfit for drinking, 44.12% were highly polluted, and only 1.17% were moderately polluted. The ERI evaluated that 12.94% of the SGW posed moderate ecological risk, while 86.47% posed low ecological risks. In addition, Pearson Correlation, Principal Component Analysis (PCA), and Cluster Analysis (CA) were performed to scrutinize the pollution source and factors influencing SGW quality. The individuality of this research was that we used different indices to determine the pollution intensities, which will be a valuable tool for indigenous planners and policymakers, surveying the decision-making and reduction of pollution activities occurring throughout the study area.

In-depth characterization of particulate matter in a highly polluted urban environment at the foothills of Himalaya-Karakorum Region.

In recent years, the rising levels of atmospheric particulate matter (PM) have an impact on the earth's system, leading to undesirable consequences on various aspects like human health, visibility, and climate. The present work is carried out over an insufficiently studied but polluted urban area of Peshawar, which lies at the foothills of the famous Himalaya and Karakorum area, Northern Pakistan. The particulate matter with an aerodynamic diameter of less than 10µm, i.e., PM10 are collected and analyzed for mineralogical, morphological, and chemical properties. Diverse techniques were used to examine the PM10 samples, for instance, Fourier transform infrared spectroscopy, x-ray diffraction, and scanning electron microscopy along with energy-dispersive x-ray spectroscopy, proton-induced x-ray emission, and an OC/EC carbon analyzer. The 24h average PM10 mass concentration along with standard deviation was investigated to be 586.83 ± 217.70µg/m3, which was around 13 times greater than the permissible limit of the world health organization (45µg/m3) and 4 times the Pakistan national environmental quality standards for ambient PM10 (150µg/m3). Minerals such as crystalline silicate, carbonate, asbestiform minerals, sulfate, and clay minerals were found using FTIR and XRD investigations. Microscopic examination revealed particles of various shapes, including angular, flaky, rod-like, crystalline, irregular, rounded, porous, chain, spherical, and agglomeration structures. This proved that the particles had geogenic, anthropogenic, and biological origins. The average value of organic carbon, elemental carbon, and total carbon is found to be 91.56 ± 43.17, 6.72 ± 1.99, and 102.41 ± 44.90µg/m3, respectively. Water-soluble ions K+ and OC show a substantial association (R = 0.71). Prominent sources identified using Principle component analysis (PCA) are anthropogenic, crustal, industrial, and electronic combustion. This research paper identified the potential sources of PM10, which are vital for preparing an air quality management plan in the urban environment of Peshawar.

Micro-PIXE imaging of the rib bones of rats

The ribs are bones that constitute the ribcage and consist of three regions: cartilage, costochondral junction with growth plate structures, and hard bone. In this study, frozen sections of rat ribs were prepared, and the distributions of calcium (Ca), phosphorus (P), potassium (K), and sulfur (S) were examined using particle-induced X-ray emission with microprobe (micro-PIXE) analysis. Areas with high Ca and P accumulation were observed in the interior of the rib cartilage. Histograms comparing the Ca accumulation in the three rib regions showed that the mode of accumulation of Ca in the cartilage are similar to that of the costochondral junction but distinct from that of the hard bone. The cartilage section did not possess an alkaline phosphatase-concentrated area that reflects the hard bone mineralization and is enriched in the costochondral junction. These data indicate differences in the mineralization process between cartilage and hard bones.

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.

Correlation between nutrients, rare earth elements and heavy metals in O. Sativa rice plant organs by instrumentation neutron activation analysis and proton induced x-ray emission techniques

The accumulation of halogens and metals from roots to stems, leaves and grains of Oryza sativa rice plant collected in Northern Senegal (St Louis region) at the same stages of growth but at different salinity soil levels was investigated by measuring their elemental concentration by invasive instrumental techniques of neutron activation analysis and proton induced x-ray emission. The normalized elemental concentration of Na, Cl, K, (Cs, Rb, Sr, Sb, Ba Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Br, Rb, Sb was correlated with one of rare earth elements, La, Ce, Sm, Yb, Nd, Eu, Tb, Tm, and Lu) and the one of the heavy metals Hf, Ta and Th and to assess their subsequent distribution within the Oryza sativa rice plant in a particular salinity environment. The exploration of the experimental data was performed by applying machine learning techniques with Python to find their elemental correlations. This study shows that the accumulation of iron is highly correlated with the amount of rare earth elements and heavy metals investigated. We observe an inverse correlation between Fe and Cl concentrations in the roots and stems of the Oryza sativa rice plant, in which higher levels of Fe in the roots relative to stems correspond to lower levels of Cl. We also remark that there is no accumulation of rare earth elements in the root tissues of the different Oryza sativa rice plants studied. Whereas, in the stem, leaf, and grain organs there is a strong correlation between metal contents and rare earth elements.

Interdisciplinary methodology for the characterisation of archaeological metal grave goods from the Museum of Patagonia by PIXE, DRX, and SEM/EDS

AbstractWe present a study of a selection of metal ornaments belonging to archaeological funerary goods from Patagonic Indigenous groups. They are part of the ‘Andrés Giai’ Collection, under the guard of the Museum of Patagonia (Nahuel Huapi National Park [PNNH]; National Parks Administration [APN]), Argentina. The absence of contextual information and its current conservation status motivated the design of an interdisciplinary methodology to develop an Integral Conservation Plan that considered the selection of analytical techniques. Here, we implemented complementary nondestructive characterisation techniques such as particle induced X‐ray emission (PIXE), X‐ray diffraction (XRD) and scanning electron microscopy coupled with energy dispersive X‐ray spectroscopy (SEM/EDS). We developed a methodology enabling us to characterise each piece with respect to its metallic composition and degradation products, and in certain cases, their manufacturing process. These findings have contributed with essential information for the tailored conservation treatment proposal. Moreover, they provided key information in regard to the reconstruction of contextual data for each piece. In addition, the methodology proposed for the Integral Conservation Plan takes into account an optimisation of the techniques to be used in order to minimise unnecessary handling of goods whilst ensuring an appropriate use of technological and economic resources whilst minimising time on potentially unconclusive measurements and results.

PIXE analysis of Late Bronze Age situlae from the eponymous Hajdúböszörmény-Csege-halom I hoard and Sényő-Dajkahegy, Northeastern Hungary

The paper introduces the particle-induced X-ray emission analysis (PIXE) of two Hajdúböszörmény-type situlae from the eponymous Hajdúböszörmény I hoard (collection of the Hungarian National Museum, Budapest) and Sényő (collection of the Jósa András Museum, Nyíregyháza). Both situlae are representative types of the period between 1080 and 960 BC, Ha B1, or the ‘Hajdúböszörmény hoard horizon’ of the Hungarian Late Bronze Age. The obtained results are significant in that they are the very first to characterise the classic Hajdúböszörmény-type situla from their core distribution area, i.e., the region where this metal vessel type was presumably produced. The paper is focused on a description of the elemental composition of these tin bronze vessels, with particular attention on the grouping of their accompanying elements and the ratio of tin. The PIXE results suggest that a rather homogenous raw material was used to produce and repair these objects, which can be correlated with the CG16 Copper Group. The ratio of tin was relatively high, mostly around 9–10 wt%; low values were only identified on one of the repaired parts of the Sényő situla and a secondarily attached copper rivet.

Multi-Technique Characterization of 3.45 Ga Microfossils on Earth: A Key Approach to Detect Possible Traces of Life in Returned Samples from Mars.

The NASA Mars 2020 Perseverance rover is actively exploring Jezero crater to conduct analyses on igneous and sedimentary rock targets from outcrops located on the crater floor (Máaz and Séítah formations) and from the delta deposits, respectively. The rock samples collected during this mission will be recovered during the Mars Sample Return mission, which plans to bring samples back to Earth in the 2030s to conduct in-depth studies using sophisticated laboratory instrumentation. Some of these samples may contain traces of ancient martian life that may be particularly difficult to detect and characterize because of their morphological simplicity and subtle biogeochemical expressions. Using the volcanic sediments of the 3.45 Ga Kitty's Gap Chert (Pilbara, Australia), containing putative early life forms (chemolithotrophs) and considered as astrobiological analogues for potential early Mars organisms, we document the steps required to demonstrate the syngenicity and biogenicity of such biosignatures using multiple complementary analytical techniques to provide information at different scales of observation. These include sedimentological, petrological, mineralogical, and geochemical analyses to demonstrate macro- to microscale habitability. New approaches, some unavailable at the time of the original description of these features, are used to verify the syngenicity and biogenicity of the purported fossil chemolithotrophs. The combination of elemental (proton-induced X-ray emission spectrometry) and molecular (deep-ultraviolet and Fourier transform infrared) analyses of rock slabs, thin sections, and focused ion beam sections reveals that the carbonaceous matter present in the samples is enriched in trace metals (e.g., V, Cr, Fe, Co) and is associated with aromatic and aliphatic molecules, which strongly support its biological origin. Transmission electron microscopy observations of the carbonaceous matter documented an amorphous nanostructure interpreted to correspond to the degraded remains of microorganisms and their by-products (extracellular polymeric substances, filaments…). Nevertheless, a small fraction of carbonaceous particles has signatures that are more metamorphosed. They probably represent either reworked detrital biological or abiotic fragments of mantle origin. This study serves as an example of the analytical protocol that would be needed to optimize the detection of fossil traces of life in martian rocks.

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.

Ionome mapping and amino acid metabolome profiling of Phaseolus vulgaris L. seeds imbibed with computationally informed phytoengineered copper sulphide nanoparticles

This study reports the effects of a computationally informed and avocado-seed mediated Phyto engineered CuS nanoparticles as fertilizing agent on the ionome and amino acid metabolome of Pinto bean seeds using both bench top and ion beam analytical techniques. Physico-chemical analysis of the Phyto engineered nanoparticles with scanning-electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier Transform Infrared Spectroscopy confirmed the presence of CuS nanoparticles. Molecular dynamics simulations to investigate the interaction of some active phytocompounds in avocado seeds that act as reducing agents with the nano-digenite further showed that 4-hydroxybenzoic acid had a higher affinity for interacting with the nanoparticle’s surface than other active compounds. Seeds treated with the digenite nanoparticles exhibited a unique ionome distribution pattern as determined with external beam proton-induced X-ray emission, with hotspots of Cu and S appearing in the hilum and micropyle area that indicated a possible uptake mechanism via the seed coat. The nano-digenite also triggered a plant stress response by slightly altering seed amino acid metabolism. Ultimately, the nano-digenite may have important implications as a seed protective or nutritive agent as advised by its unique distribution pattern and effect on amino acid metabolism.Graphical abstract

Muon spectrometers on China Spallation Neutron Source and its application prospects

<sec>The China Spallation Neutron Source Phase-II Project (CSNS-II) includes the construction of a muon source, namely “Muon station for sciEnce technoLOgy and inDustrY” (MELODY). A muon target station and a surface muon beam line will be completed as scheduled in 2029, making MELODY the first Chinese muon facility. This beam line mainly focuses on the application of muon spin relaxation/rotation/resonance (μSR) spectroscopy. The MELODY also reserves the tunnels for building a negative muon beam line and a decay muon beam line in the future, thereby further expanding the research field to muon-induced X-ray emission (MIXE) elemental analysis and μSR measurements in thick cells, respectively. The two types of material characterization technologies keep their uniqueness in multi-disciplinary researches, and also provide complementary insights for other techniques, such as neutron scattering, nuclear magnetic resonance, and X-ray fluorescence analysis.</sec><sec>The μSR spectroscopy is a mature technology for injecting highly spin polarized muon beams into various types of materials. The subsequent precession and relaxation of muon spin in its surrounding atomic environment reflect the static and dynamical properties of the material of interest, which are then measured by detecting the asymmetric emission of positrons from the decay of those muons, with an average lifetime of approximately 2.2 μs. This enables μSR to develop into a powerful quantum magnetic probe for investigating materials related to magnetism, superconductivity, and molecular dynamics. The combination of a positive muon and an electron is known as muonium, which is a unique and sensitive probe in studying semiconductors, new energy materials, free radical chemistry, etc. As the production of muon beams strongly relies on proton accelerator, only five muon facilities in the world are available for μSR experiments. This limits the large-scale application of muon related sciences. Especially, Chinese researchers face fierce competition and can only apply for precious and limited muon beam time from international muon sources to characterize the key properties of their materials.</sec><sec>The construction of the MELODY muon facility at CSNS-II aims to provide intense and pulsed muon beams for Chinese and international users to conduct their μSR measurements with high quality data in a low repetition rate operation mode. To achieve this goal, as shown in <xref ref-type="fig" rid="Figure1">Fig. 1</xref>, the μSR spectrometer is designed with 1) over 3000 detector units to obtain a sufficient counting rate of 80 Million/h to significantly suppress statistical fluctuations in a short measuring time, 2) a high asymmetry of 0.3 to greatly amplify μSR signals so as to further reduce statistical fluctuations, and 3) extendable low temperature devices to cover most μSR applications and also fulfill experiments with extreme condition requirements.</sec><sec>The MIXE elemental analysis is a type of particle induced X-ray emission (PIXE) technology. Due to the heavier mass of negative muon, the energy of muonic X-ray is around 207 higher than that of X-ray or electron induced fluorescence X-ray. Thus, the MIXE technology is more sensitive to materials with low atomic numbers, and thick samples can be effectively studied without scratching their surfaces. Due to these advantages, the MIXE has been successfully applied to the elemental analysis of cultural heritages, meteorites, Li-ion batteries, etc. MELODY reserves tunnels for negative muon extractions and transport to a MIXE terminal. The MELODY research team is developing a new detection technology with high energy resolution and high counting capability to shorten the measuring time to an acceptable amount based on the 1-Hz repetition rate of muon pulses.</sec><sec>The μSR spectroscopy and MIXE are the two most important application fields of accelerator muon beams. The MELODY muon facility aims to develop and promote these technologies in China by constructing dedicated muon beam lines in CSNS-II and in the future. In this overview, we introduce the principles and advantages of the μSR and MIXE technologies, as well as the physical design and application prospects of the μSR and MIXE spectrometers based on the CSNS-II muon source. Finally, discussions and expectations are made regarding the future upgrade of the CSNS-II muon source’s muon beamline and its broader applications.</sec>

Historical pyrite “mirrors” from the Ecuadorian Cañari culture, digital microscopy observations, mineralogical and elemental analysis

This research relies on microscopy and digital microscopy observations and spectral analysis techniques: Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS) and particle-induced X-ray emission (PIXE), to recover part of the lost identity of two pyrite (FeS2) cones. Conserved in Paris, at the Muséum National d'Histoire Naturelle (MNHN), the first one is registered MIN000-3519 in the collection of the mineralogist René-Just Haüy, the second one, registered 105.504, is a stray object. All information related to its origin would have been lost during the move (1837–1841) of the collections from the former Cabinet du Jardin du Roy to the new earth science gallery of the MNHN. Our historical research (Gendron, 2022) revealed that the first one, described as an “Inca mirror”, was shipped from Peru around 1760 by the botanist Joseph de Jussieu to his brothers Antoine and Bernard. They also confirmed that these two pyrite cones are archaeological objects of the Ecuadorian Cañari culture (500–1500 AD).Raman analyses conducted on the MIN000-3519 specimen confirm that it was developed on a quartz paragenesis. While the faces observation of no.105.504 reveals that the crystal used for its cut was triglyph twinned, a crystal which must have been cubic or dodecahedral pentagonal. The observation of the technical traces in digital microscopy makes it possible to reconstruct a process of similar cut for the two “mirrors” and help to discover red mineral clusters in the bottom of the crystalline gaps. LIBS analyses were also applied to get complementary information on in-depth element distribution, such as Fe and Al, in order to understand the stratigraphy inside the cracks. Finally, PIXE measurements do not confirm that these two pyrites come from the same deposit. But, this analytical technique is hampered by the nature of the element Fe which offers multiple and random bonding possibilities during the crystallization of iron minerals and by the lack of a comparative sample in the Parisian mineralogic collections.