We use a Zr/Si multilayer presenting a gradient of period to probe the shape of the Si L2,3 emission band (maximum around 92 eV) in and out of Bragg conditions. The sample was prepared by magnetron sputtering and its reflectance measured in the photon energy range of interest with synchrotron radiation. The study is performed on an electron microprobe equipped with a reflection zone plate spectrometer operating in the 40-120 eV photon energy range. Outside Bragg conditions, the observed spectrum is that of amorphous silicon as expected from the small thickness of the Si layers. In Bragg conditions, that is to say when the period of the multilayer, the emitted photon energy and detection angle fulfill the Bragg law, the shape and intensity of the emission band change. The main change is the intensity decrease of the shoulder present around 97 eV. Purcell-Kleppner and Kossel effects, or a combination of both, are suggested to explain the evolution of the Si L2,3 emission band when going through the Bragg conditions.

Thin films of 10B4C are effective candidate neutron convertors in the next generation of detectors when facing the limited availability of 3He. In this work, the purity-improved natural B4C films were fabricated using high vacuum magnetron sputtering methods. The base pressure of the sputtering chamber was reduced from 2 x 10-4 Pa to 2 x 10-5 Pa. The structural characteristics of B4C films, including density, surface morphology, and purity, were analyzed using X-ray reflectivity, X-ray photon spectra analysis, and scanning electron microscopy. B4C films with 1 mu m thickness, density of 2.23 g/cm3, and good adhesion to substrates were obtained. The element concentrations of the B4C films were measured and implemented in a Monte Carlo simulation developed with the tool Geant4. The determining neutron detection efficiency factors were the density and purities of B4C. The films were developed on a 50 x 50 mm GEM-based neutron detector at China Spallation Neutron Source (CSNS). The measured 21 % increase in neutron efficiency of GEM detectors agrees with that of simulations.

Ni/Ti multilayer supermirror were prepared by nitrogen-oxygen mixed gas reactive magnetron sputtering method. The effects of the flow ratio of nitrogen-oxygen mixed gas to argon (F(N2+O2)= (N2+O2)/Ar) on the growth behavior, microstructure, and stress evolution of the Ni monolayers and Ni/Ti multilayers were investigated. The results show that Ni monolayers achieve optimal surface quality with surface roughness minimized to 0.23 nm at F(N2+O2)= 5%. For the Ni/Ti multilayer films, 11th-order sharp Bragg diffraction peaks were observed at F(N2+O2)= 22.5%, with the minimum interfacial roughness (Ti-on-Ni: 0.6427 nm, Ni-on-Ti: 0.7202 nm), indicating superior periodic structural integrity and interfacial sharpness of the multilayer system under this condition. Real-time stress measurements revealed that the introduction of N2-O2 mixed gases significantly influenced the stress state of the multilayer films: under pure Ar sputtering, the films exhibited overall compressive stress; when F(N2+O2)>= 20 %, the stress state transitioned to tensile stress. A critical threshold at F(N2+O2)= 22.5% is identified, below which Ni layers maintain face-centered cubic (fcc) structure with refined grains and sharp interfaces, while phase transformation (NiO crystallization), grain coarsening, and interface deterioration take place exceeding this value.

Freestanding Zr filters are important devices for improving spectral purity in the extreme ultraviolet range of 7-20 nm, and their irradiation resistance directly determines their life and efficiency. We prepared multilayered Zr/B4C and Zr/Si filters using magnetron sputtering. Their transmittance reached a maximum of 23% (lambda =13.5 nm). Microwatt-radiation-induced structural changes in the filters were investigated at the metrology beamline (BL08B) of the National Synchrotron Radiation Laboratory. The aging of the Zr filters was measured and analyzed. The experimental results revealed that the damage was noticeable on the irradiated filter surfaces with different states, suggesting that the main factors causing the degradation of the filters were oxidation and carbon contamination at the surfaces. Furthermore, the thermal stability of the Zr filters was studied by annealing, and the heat accumulation during the damage process was estimated using finite-element numerical simulations and X-ray photoelectron spectroscopy measurements. Silicide formation at the Zr-Si-O system interfaces was found to be key to enhancing the stability of the filters.

Collagen, a key structural component of the extracellular matrix, undergoes significant remodeling during carcinogenesis. However, the important role of collagen levels in breast cancer diagnostics still lacks effective in vivo detection techniques to provide a deeper understanding. This study presents photoacoustic spectral analysis improved by machine learning as a promising non-invasive diagnostic method, focusing on exploring collagen as a salient biomarker. Murine model experiments revealed more profound associations of collagen with other cancer components than in normal tissues. Moreover, an optimal set of feature wavelengths was identified by a genetic algorithm for enhanced diagnostic performance, among which 75% were from collagen-dominated absorption wavebands. Using optimal spectra, the diagnostic algorithm achieved 72% accuracy, 66% sensitivity, and 78% specificity, surpassing full-range spectra by 6%, 4%, and 8%, respectively. The proposed photoacoustic methods examine the feasibility of offering valuable biochemical insights into existing techniques, showing great potential for early-stage cancer detection.

Boron carbide (B4C) films used as neutron conversion layers were investigated in this paper to replace the traditional 3He detectors due to their shortage. A magnetron sputtering system was developed for depositing large-size B4C films with the 1500 × 400 mm2 uniform-area. B4C films at the micron scale were deposited on aluminum (Al), float glass (SiO2), and silicon (Si) substrates with an inserting adhesion layer. The key characteristics, including surface morphology, thickness nonuniformity, purity, and neutron efficiency of B4C films, were characterized using atomic force microscopy, scanning electron microscopy, grazing incidence x-ray reflectivity, x-ray photoelectron spectroscopy, and neutron radiation metrology. The experimental results indicate that the deposition thickness nonuniformity across a 1500 × 400 mm2 area was better than ±3%. The stoichiometric ratio of boron atoms and carbon atoms (B/C) is 5.18, with 6 at. % O and 0.79 at. % N concentrations. The measured neutron detection efficiency of a 3 µm 10B4C film for 25 meV neutrons was 3.3 ± 0.3(sys)%, which is close to the simulated results (3.4%). The results show that the B4C neutron conversion layer is a promising substitute for 3He for neutron detection in the future.

Neutron scattering instruments play an important role in studying the inner structure of materials. A neutron beam monitor is a detector commonly used in a neutron scattering instrument. The detection efficiency for most neutron beam monitors is quite low (10-4-10-6). However, in some experiments with a low neutron flux, such as small angle neutron scattering (SANS) and inelastic neutron scattering experiments, a neutron beam monitor with a higher detection efficiency (∼1% for thermal neutrons) is required to reduce the duration of the experiment. To meet this requirement, a ceramic gas electron multiplier-based neutron beam monitor equipped with a 1 µm 10B4C neutron converter was developed in this study. Its performance was determined both experimentally and in simulations. The detection efficiency in the wavelength range of 1.8-5.5 Å was measured experimentally and was confirmed by the simulation results. An algorithm based on event selection and position reconstruction was developed to improve the spatial resolution to about 1 mm full-width-half-maximum. The wavelength spectrum was measured in beamline 20 (BL20) and agreed well with the results obtained using a commercial monitor. The maximum counting rate was 1.3 MHz. The non-uniformity over the whole 100 × 100 mm2 active area was determined to be 1.4%. Due to the excellent performance of this monitor, it has been used in several neutron instruments, such as the SANS and the High-Energy Direct-Geometry Inelastic Spectrometer instruments in the China spallation neutron source.

Neutron conversion detectors that use 10B-enriched boron carbide are feasible alternatives to 3He-based detectors. We prepared boron carbide films at micron-scale thickness using direct-current magnetron sputtering. The structural characteristics of natural B4C films, including density, roughness, crystallization, and purity, were analyzed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, and scanning electron microscopy. A beam profile test was conducted to verify the practicality of the 10B-enriched B4C neutron conversion layer. A clear profile indicated the high quality of the neutron conversion of the boron carbide layer.

Meter-scale optical films have become core components in large-size optical systems. Improving film thickness uniformity is a crucial issue to ensure optical properties. Ag films are commonly used as high-reflection mirrors for optical systems. Here a meter-scale magnetron sputtering equipment has been independently developed for coating Ag films. Two strategies were performed to correct the film thickness uniformity in the horizontal direction and vertical directions respectively. Specifically, the film thickness uniformity at the horizontal position was guaranteed by scanning the target parallel to the horizontal direction. Meanwhile, a mask was designed to optimize vertical film thickness uniformity. The film thickness, fitted by X-ray reflectometry (XRR), non-uniformity is less than 3% both in the 1800 mm range of the horizontal direction and the 1100 mm range of the vertical direction. This study has brought new insight into the development of meter-scale thin film optics.

Inthis paper, high-quality beta-Ga2O3 filmswere grown on silicon substrates by plasma-enhancedatomiclayer deposition (PEALD). Effects of annealing temperature on beta-Ga2O3 thin films were studied. Atomic force microscopy(AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS),X-ray reflection (XRR), and ultraviolet (UV) emission spectroscopywere used to systematically characterize Ga2O3 thin films. AFM test results showed that as annealing temperatureincreased from 500 to 900 degrees C, the roughness of film increasedfrom 0.542 to 1.58 nm. XPS test results showed that the concentrationof oxygen vacancies in annealed films was significantly reduced. Afterannealing, the energy band of the film increased from 4.73 to 5.01eV, and the valence band maximum (VBM) increased from 2.58 to 2.67eV, indicating that the annealing treatment under a nitrogen atmospherecan improve the quality of films. Results demonstrate that high-qualityGa(2)O(3) films can be obtained by the annealingprocess after atomic layer deposition (ALD). The proposed method canrealize an ideal stoichiometric ratio of the Ga2O3 thin film as well as precise control of its optical, electrical,and microstructural properties. This work lays the foundation forfuture application of Ga2O3 materials in photoelectricdetection, power devices, transparent electronics, and other fields.

Zirconium is a perspective material for freestanding filters at the EUV range. To optimize the optical performance and irradiation stability of Zr-based filters, multilayered Zr/B4C and Zr/Si filters with transparency of above 23% (λ = 13.5nm) were designed and studied in this paper. These samples were characterized in detail by X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The XPS results of the Zr/Si film under 300℃ annealing indicate the formation of zirconium silicide in the Zr-Si-O system at the interfaces, contributing to improving the thermal stability and resistance to oxidation. Radiation aging tests were carried out using the 13.5nm EUV source at the metrology beamline (BL08B) of the National Synchrotron Radiation Laboratory (NSRL). The aging in transparency of all the samples was observed and discussed for the first time. It is concluded that the main factors causing the degradation of the filters were oxidation and carbon contamination at the surfaces. Compared with monolayer and Zr/B4C filters, the Zr/Si filters show higher thermal stability and radiation resistance, indicating that Si possesses acceptable optical performance as the spacing and capping layer for Zr-based filters.

Ni/Ti multilayers were reactively deposited with a gas mixture of Ar, N2 and O2 using the magnetron sputtering, while (N2 + O2)/Ar flow ratio during the sputtering process was varied. A detailed study on the microstructure evolution and interfacial properties was performed using grazing incidence X-ray reflectivity, X-ray diffraction, X-ray photoelectron spectroscopy, X-ray diffuse scattering, and transmission electron microscopy. With the in-crease in (N2 + O2)/Ar flow ratio, the grain size in Ni layers first decreases and then increases at a critical point of 25.0 %, followed with the crystal phase transforming from Ni into NiO. The mechanism of microstructure evolution in Ni layers due to N2 and O2 gas incorporation is discussed in this paper. The interfaces of Ni/Ti multilayer are smoothened due to a decrease in the size of Ni grains. Meanwhile, the interfacial effects including the vertical replication of interfacial roughness and the diffusion between adjacent Ni and Ti layers are sup-pressed for the N2 and O2 gas incorporation. Furthermore, the lateral correlation length of interfacial roughness varies with (N2 + O2)/Ar flow ratio, which presents the relevance with the grain size.

Multilayer interference mirrors play a pivotal role in spectroscopic diagnostic systems, which probe electron temperature and density during inertial confinement fusion processes. In this study, aperiodic Mo/B 4 C multilayer mirrors of varied thicknesses were investigated for X-ray plasma diagnostics at the 9.67-keV W-Lβ line. The thickness distribution of the aperiodic multilayers was designed using the first Bragg diffraction condition and then optimized through a simplex algorithm to realize a narrow bandwidth and consistent spectral response. To enhance spectral accuracy, further refinements were undertaken by matching the grazing incidence X-ray reflectivity data with actual structural parameters. X-ray reflectivity measurements from the SSRF synchrotron radiation facility on the optimized sample showed a reflectivity of 29.7 ± 2.6%, flat-band range of 1.3 keV, and bandwidth of 1.7 keV, making it suitable for high-temperature plasma diagnostics. The study explored the potential of predicting the 9.67 keV reflectivity spectrum using the fitting data from the grazing incidence X-ray reflectivity curves at 8.05 keV. Additionally, the short-term thermal stability of an aperiodic multilayer was assessed using temperature-dependent in situ X-ray measurements. Shifts in the reflectivity spectrum during annealing were attributed to interdiffusion and interfacial relaxation. The research team recommends the aperiodic Mo/B 4 C multilayer mirror for operations below 300 ℃.

Metallic glasses are spatially heterogeneous at the nanometer scale.However,the effects of external excitation on their structural and mechanical heterogeneity and the correlation to their properties are still unresolved.Nanoindentation,atomic force microscopy(AFM)and high-resolution transmission electron microscopy(HRTEM)were carried out to explore the effects of cryo-genic thermal cycling(CTC)on mechanical/structural heterogeneity,nanoscale creep deformation and optical properties of nanostructured metallic glass thin films(MGTFs).The results indicate that CTC treatment alters the distribution fluctuations of hardness/modulus and energy dissipation and results in an increase-then-decrease variation in mechanical heterogeneity.By applying Max-well-Voigt model,it can be shown that CTC treatment results in a remarkable activation of more defects with longer relaxation time in soft regions but has only a slight effect on defects in hard regions.In addition,CTC treat-ment increases the transition time from primary-state stage to steady-state stage during creep deformation.The enhanced optical reflectivity of the MGTFs after 15 ther-mal cycles can be attributed to increased aggregation of Cu and Ni elements.The results of this study shed new light on understanding mechanical/structural heterogeneity and its influence on nanoscale creep deformation and optical characteristics of nanostructured MGTFs,and facilitate the design of high-performance nanostructured MGTFs.

Since the growth morphology along and perpendicular to the interface is important for supermirror applications, the dependence of this on the reactive gas has been investigated in Ni/Ti multilayers prepared by reactive magnetron sputtering with variable O _2 /N _2 ratios. The interface properties are characterized by GIXRR, XDS, and TEM measurements. Compared to the case without O _2 , the presence of 20% O _2 in the deposition of Ni layers contributes to smooth and abrupt interfaces. It also suppresses the accumulation of interfacial roughness with the increasing number of layers. However, the abundant oxygen content results in a striking degradation of interface quality associated with the crystallization evolution. Moreover, the lateral correlation length of interfacial roughness exhibits a consistent tendency with the grain size as the oxygen content increases. Following the XPS depth profiles, although N _2 and O _2 gases were applied in the Ni layer deposition, the N and O were only detected in the Ti layers as the compound for the high chemical activity of Ti. The elemental form in the Ni layers corresponds to the crystalline structure inferred by XRD measurements.

In this work, the characteristics of the gallium oxide (Ga2O3)/diamond heterostructure were thoroughly examined after the preparation of Ga2O3 thin film on bulk diamond via atomic layer deposition. The X-ray diffraction (XRD) analysis revealed the Ga2O3 film amorphous and diamond polycrystalline. The atomic force microscopy (AFM) mapping displayed remarkably smooth surfaces of the Ga2O3 film and diamond substrate (RMS of 0.184 and 0.508 nm, respectively). The scanning electron microscopy (SEM) images showed conspicuous grains formed on the diamond, and small crystallites on the surface of the film. The optical characteristics were investigated via spectroscopic ellipsometry (SE) and UV/Vis/NIR spectrophotometer. Raman spectroscopy suggested a sharp diamond-related (sp3) peak and an extremely weak bulge band around 1350-1620 cm- 1. X-ray photoelectron spectroscopy (XPS) analysis indicated Ga2O3/diamond heterojunction to be staggered (type II) band alignment with valence band and conduction band offsets of around 1.18 eV and 2.09 eV, respectively. Moreover, according to time-domain thermoreflectance (TDTR) measurements, the thermal conductivity of Ga2O3 and the thermal boundary conductivity of the heterointerface were 5.13 W/(m center dot K) and 19.22 MW/(m2 center dot K), respectively. These findings not only demonstrate the feasibility of Ga2O3-on-diamond hetero-integration but open up new prospects for the design and physical analysis of Ga2O3/diamond-based devices in the future.

Breast cancer threatens the health of women worldwide, and its molecular subtypes largely determine the therapy and prognosis of patients. However, an uncomplicated and accurate method to identify subtypes is currently lacking. This study utilized photoacoustic spectral analysis (PASA) based on the partial least squares discriminant algorithm (PLS-DA) to identify molecular breast cancer subtypes at the biomacromolecular level in vivo. The area of power spectrum density (APSD) was extracted to semi-quantify the biomacromolecule content. The feature wavelengths were obtained via the variable importance in projection (VIP) score and the selectivity ratio (Sratio), to identify the biomarkers. The PASA achieved an accuracy of 84%. Most of the feature wavelengths fell into the collagen-dominated absorption waveband, which was consistent with the histopathological results. This paper proposes a successful method for identifying molecular breast cancer subtypes and proves that collagen can be treated as a biomarker for molecular breast cancer subtyping.

X-rays have developed into an essential tool in variety of fields, such as biology, materials, chemistry, and physics etc. Numerous X-ray types, including the orbital angular momentum (OAM), the Laguer re-Gauss, and the Hermite-Gauss states, have been proposed. This greatly enhances the depth of application of X-ray. The X-ray states described above are mostly produced by binary amplitude diffraction elements. In light of this, this paper proposes a flat X-ray diffraction grating based on caustic theory to generate Airy-type X-ray. It is proved by the simulation of multislice method that the proposed grating can generate the Airy beam in the X-ray field. The results show that the generated beams have a secondary parabolic trajectory deflection with the propagation distance, which is consistent with the theory. Inspired by the success of Airy beam in light-sheet microscope, the Airy-type X-ray can be anticipated to enable novel image capability for bio or nanoscience.

The effects of post-deposition oxygen annealing temperature on the physical, chemical, and optical properties of gallium oxide (Ga2O3) films were systematically studied in this work. First, Ga2O3 films were deposited on Si (100) substrates by atomic layer deposition (ALD) and then annealed at 500 to 900 ℃ , respectively. Several standard surface analysis methods were used to characterize the Ga2O3 films before and after annealing. X-ray diffraction (XRD) pat­terns illustrated that the as-deposited (as-dep) amorphous film transitioned to β-phase after annealing at temperatures greater than 600 ℃. Atomic force microscopy (AFM) images showed that the grain size and roughness of the films significantly increased when an­nealed above 700 ℃ . The effects of the annealing process on optical properties were performed using photoluminescence spectroscopy (PL) and spectroscopic ellipsometry (SE). Moreover, X-ray spectroscopy (XPS) was utilized to extract the oxygen vacancy (VO ) concentration, bandgap, and the energy band alignment of Ga2O3 . With increasing annealing temperature, it was found that the atomic ratio of O/Ga increased while VO decreased monotonically from 47.4% to 27.0%. Density functional theory (DFT) simulation further accounted for energy band shifts resulting from the variation of VO. This study provides a means to achieve high-quality β -Ga2O3 films, highly significant for applications of β-Ga2O3-based ultraviolet photodetectors and other rele­vant devices.

Because of the precise control of film thickness, atomic layer deposition (ALD) offers significant advantages in fabricating high-quality superlattice films. For the first time, a SiNx/SiO2 superlattice with an ultrathin SiNx sublayer layer (1.5 nm) and a SiO2 barrier layer (3 nm) was successfully fabricated using plasma-enhanced ALD. Transmission electron microscopy (TEM) measurements demonstrate the maintenance of multilayer structures with smooth interfaces. Next, the annealing effect on the microstructural, optical, and chemical properties of these SiNx/SiO2 superlattice structures was thoroughly investigated. With increasing annealing temperature, Xray reflection (XRR) and TEM measurements revealed consistent changes in interface, morphology, roughness, density, and thickness. After high-temperature annealing, Fourier-transform infrared spectroscopy (FTIR) measurements combined with X-ray photoelectron spectroscopy (XPS) measurements revealed significant reductions in Si-H-related defects and absorption bands. Photoluminescence (PL) was used to characterize the light emission property, and it was discovered that increasing the annealing temperature decreased the PL peak intensity at -550 and 900 nm. The silicon nanocrystals (Si-NCs)-related PL peak (-900 nm) became dominant as the annealing temperature increased. The findings in this paper shed light on the annealing effect on the new superlattice material prepared via ALD. Improved PL properties of this type of superlattice are expected and can be obtained in future research by optimizing the ALD deposition process and annealing parameters.