Ag Lα Research Articles

Li2B4O7 XPS using monochromatic Ag Lα x rays

XPS spectra of lithium tetraborate (Li2B4O7) were obtained using an Ag Lα (2984.3 eV) source and a quartz (1010) crystal monochromator through second order diffraction. Irradiation occurs on the sample at 54.7° to the surface normal. Spectra of the principal lines include O 1s, C 1s, B 1s and Li 1s. Spectra of O KLL, O 2s and Valence band were also acquired. Quantitative analysis was performed using Cant sensitivity factors.

Determination of Antioxidant, Cytotoxicity, and Anti-human Lung Cancer Properties of Silver Nanoparticles Green-Formulated by Foeniculum vulgare Extract Combined with Radiotherapy.

The current investigation involved the silver nanoparticles green synthesis utilizing the aqueous extract derived from the Foeniculum vulgare leaves (AgNPs@FV). The effectiveness of these newly developed nanoparticles in conjunction with radiotherapy was evaluated on lung cancer cells. The synthesized AgNPs@FV underwent characterization through various analytical techniques such as energy dispersive X-ray (EDX), field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV-Vis) spectrophotometry. The efficacy of AgNPs@FV in conjunction with radiotherapy against human lung cancer was assessed through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The AgNPs@FV exhibited a spherical morphology ranging in size from 10.16 to 42.74 nm. The EDX diagram of nanoparticles shows energy signals at 3.02 and 2.64 keV, which are attributed to Ag Lβ and Ag Lα, respectively. During the antioxidant evaluation, AgNPs@FV and butylated hydroxytoluene (BHT) displayed IC50 values of 166 and 59 µg/mL, respectively. The cells treated with AgNPs@FV in conjunction with radiotherapy were evaluated using the MTT assay over 48h to determine cytotoxicity and anti-human lung cancer characteristics on normal (human umbilical vein endothelial cell (HUVEC)) and lung cancer cells and exhibited IC50 values of 211, 166, and 296µg/mL against NCI-H2126, NCI-H1299, and NCI-H1437, respectively. Furthermore, the malignant lung cell viability decreased when treated with a combination of AgNPs@FV and radiotherapy. Based on the aforementioned findings, it is possible that the newly developed AgNPs@FV could serve as a novel chemotherapeutic medication or adjunct for addressing lung cancer following the completion of clinical trials involving human subjects.

PINK: a tender X-ray beamline for X-ray emission spectroscopy.

A high-flux beamline optimized for non-resonant X-ray emission spectroscopy (XES) in the tender X-ray energy range has been constructed at the BESSY II synchrotron source. The beamline utilizes a cryogenically cooled undulator that provides X-rays over the energy range 2.1 keV to 9.5 keV. This energy range provides access to XES [and in the future X-ray absorption spectroscopy (XAS)] studies of transition metals ranging from Ti to Cu (Kα, Kβ lines) and Zr to Ag (Lα, Lβ), as well as light elements including P, S, Cl, K and Ca (Kα, Kβ). The beamline can be operated in two modes. In PINK mode, a multilayer monochromator (E/ΔE ≃ 30-80) provides a high photon flux (1014 photons s-1 at 6 keV and 300 mA ring current), allowing non-resonant XES measurements of dilute substances. This mode is currently available for general user operation. X-ray absorption near-edge structure and resonant XAS techniques will be available after the second stage of the PINK commissioning, when a high monochromatic mode (E/ΔE ≃ 10000-40000) will be facilitated by a double-crystal monochromator. At present, the beamline incorporates two von Hamos spectrometers, enabling time-resolved XES experiments with time scales down to 0.1 s and the possibility of two-color XES experiments. This paper describes the optical scheme of the PINK beamline and the endstation. The design of the two von Hamos dispersive spectrometers and sample environment are discussed here in detail. To illustrate, XES spectra of phosphorus complexes, KCl, TiO2 and Co3O4 measured using the PINK setup are presented.

Quantification of aluminium and silicon‐containing materials using Ag Lα X‐rays

In recent years, instrument manufacturers have been providing laboratory‐based HAXPES (hard X‐ray photoelectron spectroscopy) instruments that have monochromated silver Lα, chromium Kα and gallium Kα X‐ray sources. To be more than a qualitative tool, two things are required: calibration of the signal intensity as a function of kinetic energy (spectrometer response function) and relative sensitivity factors. This is now possible because of routines being available to generate the spectrometer response functions for dual Al Kα/Ag Lα X‐ray sources and the availability of Cant average matrix relative sensitivity factors (AMRSFs). However, to improve accuracy when using the Cant AMRSF care needs to be taken in the definition of the peak areas being used. This is because they need to include the total intrinsic signal that often extends beyond the main peak. This is a particular challenge when quantifying using the Al 1s peak generated with Ag Lα X‐rays as some of the intrinsic signal overlaps with the Al KLL Auger peak. When materials include both aluminium and silicon atoms, the Si 2s and 2p peaks sit upon extended signals coming from the Al 2s and 2s peaks, respectively. Thus, quantification should be limited to using the main peak area, which necessitates different relative sensitivity factors (RSFs). Using polydimethylsiloxane (PDMS) and sapphire (Al2O3) as model systems, experimental RSFs have been determined for use with the main peaks for O 1s, Al 1s, Al2s Al 2p, Si 1s, Si 2s and Si 2p subshells normalized to the RSF of the carbon 1s main peak.

Silver nanoparticles green-formulated by a medicinal plant for the treatment of pancreatic, colorectal, and gastric cancers

Pancreatic, colorectal, and gastric cancers are common cancers with severe clinical signs. Finding a new anticancer supplement or drug inside of the chemotherapeutic drug is valuable. We synthesized iron nanoparticles containing pomegranate fruit aqueous extract for investigating anti-pancreatic cancer, anti-colorectal cancer, and anti-gastric cancer, cytotoxicity, and antioxidant effects. The AgNPs synthesized using green formulation underwent characterization through FT-IR, UV–Vis, FE-SEM, TEM, EDX, and XRD techniques. The UV–Vis spectroscopy analysis revealed that the nanoparticles displayed peak absorption at around 442 nm. The peaks at 77.105, 64.205, 44.180, and 37.835 corresponding to silver nanoparticles (311), (220), (200), and (111) diffraction planes, indicate the AgNPs formation. The signals at energy of 2.64 and 3.02 keV are assigned for Ag Lα and Ag Lβ. The signals 0.27 (for C Lα) and 0.52 (O Lα) prove the secondary metabolites linkage of extract to the synthetic silver nanoparticles surface. In vitro experiments, after 3–4 passages, the cancer cells (colorectal carcinoma (Ramos.2G6.4C10 and HT-29), gastric cancer (KATO III and MKN45), and pancreatic cancer (MIA PaCa-2 and PANC-1)) and normal cell (HUVEC) were prepared in number and morphology terms. After separating the cells from the flask surface using trypsin-EDTA, the viability and count of the cells were evaluated. Subsequently, a total of 3 × 103 cells were cultured, with the option of including or excluding nanoparticles. IC50 of silver nanoparticles was 183, 209, 203, 218, 228, and 157 on Ramos.2G6.4C10, HT-29, KATO III, MKN45, MIA PaCa-2, and PANC-1 cancer cells. In this research, the maximum antioxidant effectiveness against DPPH was documented to be around 100 % when tested 1000 μg/ml.

Retrieving images from tarnished daguerreotypes using X-ray fluorescence imaging with an X-ray micro beam with tunable energy

We report recent observations using a synchrotron X-ray micro-beam to retrieve images from tarnished 19th century daguerreotypes. We confirm that high quality image can always be retrieved from tarnished plates using Hg Lα XRF as long as the bulk of the image particles and their distribution remains intact. We also report results from using tunable tender X-rays (2 - 7 keV) to conduct imaging in high vacuum at energy above the Ag L-edge and the Hg M-edge, extracting images using Ag Lα and Hg Mα, respectively among others (e.g., S to track corrosion). Images obtained with the surface sensitive total electron yield (TEY) and the bulk sensitive fluorescence yield (FLY) as well as corresponding micro-XANES are reported. Flux tolerance to high intensity X-beam is also explored. These results and their implications for cultural heritage research are discussed.

Silicon dioxide by Ag Lα, hard x-ray photoelectron spectroscopy

Silicon dioxide powder was characterized by hard x-ray photoelectron spectroscopy (HAXPES) with an Ag Lα (2984.2 eV) excitation source. The sample was fixed to a stainless-steel sample holder with copper double-sided adhesive tape. Survey spectrum, C 1s, O 1s, Si 1s, Si KLL, Si 2s, and Si 2p core levels spectra were acquired.

Platinum thin film by Ag Lα, hard x-ray photoelectron spectroscopy

Pt thin film was characterized by hard x-ray photoelectron spectroscopy (HAXPES) with an Ag Lα (2984.3 eV) excitation source. Sample was fixed to a stainless-steel sample holder with a copper double-sided adhesive tape. The survey spectrum, Pt 3d, Pt 4f, Pt 4d, C 1s, and valence band core levels spectra were acquired.

Prevention of lipopolysaccharide-induced acute kidney injury in mice by Tragopogon dubius green-mediated silver/palladium nanoparticles and its potential mechanisms

The green synthesis of bi-metallic nanoparticles has achieved great attraction due to the wide variety of their applications especially in medicinal fields. Silver/palladium NPs are a noble metallic of this class of compounds. In this study, Ag/Pd NPs were green synthesized in aqueous media in the presence of Tragopogon dubius extract. The NPs were characterized by techniques of FT-IR, XRD, FE-SEM, and EDX. Ag/Pd@ Tragopogon dubius was formed in the spherical morphology with an average crystal size of 31.77 nm. For the FT-IR spectrum of Ag/Pd@ Tragopogon dubius the peaks at 482, 504, 567, and 637 1/cm correlate to silver/palladium- oxygen bonds. The signals at 2theta values of 38.15, 44.25, 64.22, and 76.40 are indexed to the planes of (111), (200), (220), and (311) in XRD. The particle size of Ag/Pd@ Tragopogon dubius is ranged up to 55 nm. According to the EDX result, the presence of silver and palladium is approved by the four signals around 3 Kev. The signals belong to Pd Lα, Ag Lα, Pd Lβ, and Ag Lβ. The Signals at 0.3 and 0.53 Kev are related to oxygen and carbon. In the in vivo design, mice treated by Ag/Pd@ Tragopogon dubius nanoparticles, then the acue kidney injury was induced by lipopolysaccharide. On 10th day, all animals were anesthesized and blood and kidney were separated. The blood serum gained for determining the BUN and creatinine and left kidneys were frozen for cellular and molecular studies and half of right kidneys were stained through H & E and PAS and another half was sent for IHC staining. According to the results, KIM-1 and NGAL were expressed at very high levels in the untreated group and a significant decrease was seen at the control group; but, administration of 10 and 40 µg/kg Ag/Pd@Tragopogon dubius nanoparticles significantly decreased KIM-1 and NGAL expression. Ag/Pd@Tragopogon dubius nanoparticles treatment significantly attenuated lipopolysaccharide-induced reactive oxygen species generation. Serum creatinine and BUN levels, which are renal function biomarkers, were significantly decreased in Ag/Pd@Tragopogon dubius nanoparticles treatment. Tubular cell necrosis and renal tubular vacuolation were seen in lipopolysaccharide-injected mice, and the Ag/Pd@Tragopogon dubius nanoparticles administration attenuated lipopolysaccharide-induced structural injury.

Depth profiling of AlN and AlxGa1−xN crystals by XPS using Al Kα and Ag Lα line excitation and Ar ion gas cluster ion source

AlGaN-based heterostructures are promising candidates for the fabrication of ultraviolet light-emitting diodes. The analysis of the atomic composition of the grown epitaxial films is important from a technological point of view, allowing precise control over the wavelength and intensity of the emitted light. In this work, the depth profiling of AlN(0001), AlGaN(0001), and AlGaN quantum dot surfaces grown by molecular beam epitaxy was carried out by using angle-resolved x-ray photoelectron spectroscopy (XPS) combined with Ar gas cluster ion source (GCIS) sputtering. Core level shifts in XPS spectra measured by Al Kα and Ag Lα photon sources were determined. We found that sputtering by Ar1000+ ion clusters with an energy of 10 keV creates disorder on the surface and induces changes in surface atomic composition. As a result, depth profiling with a typical surface-sensitive Al Kα photon source is affected by the damaged layer. The application of a less surface-sensitive Ag Lα photon source with high photon energy could suppress the contribution from the damaged surface layer. Combining GCIS sputtering with Ag Lα line XPS measurements is, therefore, very promising for the quantification of atomic composition in the buried epitaxial layers or heterostructures with thicknesses of several tens of nm.

γ-Al2O3 by Ag Lα, hard x-ray photoelectron spectroscopy

γ-alumina (γ-Al2O3) powder was characterized by hard x-ray photoelectron spectroscopy with an Ag Lα (2984.2 eV) excitation source. The sample was fixed to a stainless-steel sample holder with copper double-sided adhesive tape. Survey spectrum, C 1s, O 1s, Al 1s, Al KLL, Al 2s, and Al 2p core levels spectra were acquired.

Formation of cesium carbonate in ion-implanted graphite, examined with dual-source x-ray photoelectron spectroscopy, density functional theory calculations and thermodynamic modelling

A sample of highly orientated pyrolytic graphite (HOPG) was implanted with Cs+ ions in order to study the effect on the graphite matrix and the chemical form of Cs once embedded. The mean implantation depth was calculated to be ∼22 nm, allowing for investigation with X-ray Photoelectron Spectroscopy, (XPS), where both a traditional Al Kα X-ray source and a higher energy Ag Lα source was used for an increased sampling depth deeper into the surface. Analysis found that there was a reduction of sp2 C–C bonding with increasing implantation dose, resulting in a total loss of sp2 character at ∼6 atomic % Cs+. A striking increase in higher binding energy components (285.8–289.4 eV) in the C 1s spectra cannot be attributed solely to the presence of C–O species, instead indicating a dramatic re-ordering of the graphitic lattice to accommodate and neutralize the embedded Cs. XPS analysis indicates the formation of cesium carbonate within the graphitic material; this is reinforced by analysis of a Cs2CO3 reference sample. Additionally, thermodynamics equilibrium simulations, supported by simplified density functional theory (DFT) calculations, are performed, leading to strong agreement with the XPS findings; that is, the most stable form of Cs within the graphite matrix is expected to be cesium carbonate (Cs2CO3), which is in thermodynamic equilibrium with degraphitised HOPG and oxygenated degraphitised HOPG.

XPS analysis of group IVA elements using monochromatic Ag Lα x rays

XPS spectra of group IVA elements (Si, Ge, Sn, and Pb) were obtained using monochromatic Ag Lα excitation. Survey, high resolution photoelectron region, and x-ray induced Auger spectra were recorded from Ar+ ion cleaned materials.

Gold, silver, and copper reference spectra for XPS instruments with monochromatic Ag Lα sources

This article provides calibration spectra for determining the transmission function of an XPS instrument operating with an Ag Lα (2984.3 eV) source monochromated with a quartz (1010) crystal through second order diffraction and irradiating the sample at 54.7° to the surface normal.

MoS2 by XPS using monochromatic Ag Lα x rays

XPS spectra of molybdenum disulfide mineral were obtained using monochromatic Ag Lα radiation. Spectra include Mo 2p, Mo 3d, Mo 3s, S 1s, S 2p, and S 2s. A flake was mechanically exfoliated from a MoS2 bulk single crystal for the study. Quantitative comparison was performed using Cant sensitivity factors.

First row transition metals Fe, Co, Ni, Cu, and Zn analyzed by XPS using monochromatic Ag Lα x rays

XPS spectra of five first row transition metals (Fe, Co, Ni, Cu, and Zn) were obtained using monochromatic Ag Lα radiation. Survey and high resolution photoelectron region (2p, 2s, 3p, and 3s) and x-ray induced Auger spectra were recorded from Ar+ ion cleaned metal foils.

Measurements of the quantitative analytical depth resolution at evaporated aluminium- and silver-layers with the FEG-EPMA JEOL JXA-8530F

The aim of this study is to extend our general approach to the spatial resolution in the quantitative element analysis that can be achieved with a FEG-EPMA by systematic measurements of the depth resolution. The test specimens are Al and Ag surface layers with various thicknesses on top of non-fluorescent substrates. By choosing an appropriate X-ray line and by varying the primary electron energy, E0 , we determined the minimum value of E0 for which the depth of the signal source volume is identical to the layer thickness. This value is defined as the depth resolution. With respect to the excitation energy of the characteristic X-rays, the depth resolution for the quantitative element analysis is found to be below 150 nm for Al (Kα at 3 kV) as well as for Ag (Lα at 5 kV).The prediction of the depth resolution at low primary electron energy E0 by means of calculations of the ionisation range of electrons or by Monte Carlo (MC) simulations is quite inaccurate because both predict better values compared to the measurements. Since we regard test specimens without disturbing secondary fluorescence it is obvious that both calculations and simulation predict too small signal source volumes for a so far unknown reason. The same discrepancy was observed for the determination of the lateral quantitative resolutions in previous studies. Therefore systematic measurement errors can be excluded. The measurements presented in this paper are very helpful for further improvements of calculations and MC-simulations at low primary electron energies E0 because specimens without secondary fluorescence are considered only.

Understanding adhesion of gold conductive films on sodium-alginate by photoelectron spectroscopy

Ultrathin layers of gold, from 2 to 25 nm of nominal coverage, have been deposited on sodium-alginate biopolymer foils applying two alternative approaches: low power sputtering and thermal evaporation. The morphology of the deposited layers was obtained by means of atomic force microscopy. In the early stages of growth, thermal evaporation gives rise to a top surface resembling the underlying substrate, whereas low power sputtering produces a topography characterized by smoother areas. This indicates that the film growth occurs in different ways. X-ray photoelectron spectroscopy with two photon energies, corresponding to Al Kα and Ag Lα photons, was used to get information on the chemistry at the interface and on the degree of intermixing between Au and sodium-alginate. While no chemical modifications with respect to the bare materials could be detected, the evolution of the intensities of the relevant core levels of Au and sodium alginate (Au 4f and Na 1s in particular) indicated a strong intermixing in the case of films deposited by low power sputtering. This is further supported by optical measurements. The observed behaviour can be correlated with the enhanced adhesion of sputtered films compared to thermally evaporated ones.

Intensity calibration and sensitivity factors for XPS instruments with monochromatic Ag Lα and Al Kα sources

This paper provides a description of the transmission function of an X‐ray photoelectron spectroscopy (XPS) instrument operating with exchangeable Al Kα (1486.6 eV) and Ag Lα (2984.3 eV) sources. Both sources use the same quartz crystal monochromator and illuminate the same area of the sample. The transmission‐function–corrected data from sputter cleaned gold provides a useful reference material to calibrate other instruments of the same type. Sensitivity factors for Ag Lα and Al Kα are calculated from photoionisation cross sections and electron effective attenuation lengths. These compare well with previous experimental values and data acquired from ionic liquids. The intensity of the Ag Lα source is found to be approximately 50 times lower than the Al Kα source. This, coupled with generally lower photoemission efficiencies, results in noisier data or extended acquisition times. However, there are clear advantages to using the Ag Lα source to analyse certain elements where additional core levels can be accessed and for many technologically important elements where interference from Auger electron peaks can be eliminated. The combination of calibrated data from both sources provides direct and easily interpreted insight into the depth distribution of chemical species. This could be particularly important for topographic samples, where angle resolved experiments are not always helpful. We also demonstrate, using thin coatings of chromium and carbon, that the inelastic background in Ag Lα wide‐scan spectra has a significantly increased information depth compared with Al Kα.

A Multi-Technique Approach for a Complete Thin Film Characterisation

Here we provide an overview of a multi-technique investigation of layered thin film and ultra-thin film coatings. Surface sensitive analytical techniques are chosen for their different sampling depths and include a combination of conventional Al Kα and higher photon energy Ag Lα excited XPS, angle resolved X-ray photoelectron spectroscopy (ARXPS) with maximum entropy method (MEM) reconstruction of concentration depth profiles and argon cluster depth profiling.