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Development of high-speed vacuum ultraviolet spectroscopy using a modified Seya-Namioka monochromator and channel electron multiplier detector in the HL-2A tokamak
摘要： A high-speed vacuum ultraviolet monochromator is developed for the HL-2A tokamak through the introduction of a novel channel electron multiplier in a modified Seya-Namioka spectrometer. A good signal to noise ratio of above 2000 is attained in the development phase of the system with typical operating parameters for observing routine HL-2A plasmas. The wavelength calibration is performed using characteristic line emissions from a hollow cathode light source with helium and argon discharges. The first measurement result of the monochromator at a sample rate of 60 kHz is presented in comparison with the visible Dα signals.
关键词： channel electron multiplier detector,HL-2A tokamak,Seya-Namioka monochromator,high-speed vacuum ultraviolet spectroscopy
更新于2025-09-09 09:28:46
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Ultrawide‐Bandgap Amorphous MgGaO: Nonequilibrium Growth and Vacuum Ultraviolet Application
摘要： New ultrawide-bandgap (>6.0 eV) photosensitive materials are in urgent need to meet the requirements of vacuum-ultraviolet (VUV) photodetection applied in deep space exploration. Here, a nonequilibrium growth method is reported to fabricate amorphous MgGaO (a-MgGaO) films with an ultrawide bandgap of 6.0 eV and an ultrashort absorption edge of 206 nm by alloying MgO and Ga2O3. By combining the as-grown films with p-type graphene (p-Gr) which serves as a transparent conductor, a vacuum-ultraviolet photovoltaic detector of p-Gr/a-MgGaO/n-SiC (n-type SiC) is constructed. The device exhibits an excellent VUV spectral selectivity with a VUV (185 nm)/UV (250 nm) rejection ratio exceeding 103, high photoresponsivity (≈10.3 mA W?1) under 0 V bias, and ultrafast response and recovery time of 1.94 μs and 0.6 ms, respectively. The reported nonequilibrium growth method is expected to have tremendous potential in fabricating ultrawide-bandgap oxide compounds, and finally facilitate future deep space exploration.
关键词： nonequilibrium growth,vacuum-ultraviolet photodetection,graphene,band engineering,MgGaO
更新于2025-09-04 15:30:14
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Separation and Pre–Concentration of Metal Cations – DNA/RNA Chelates Using Molecular Beam Mass Spectrometry with Tunable Vacuum Ultraviolet (VUV) Synchrotron Radiation and Various Analytical Methods
摘要： Separation and pre–concentration procedures such as Liquid–Liquid Extraction (LLE), Solid Phase Extraction (SPE) and Homogenous Liquid–Liquid Extraction (HLLE) make it feasible to determine the trace of metal cations such as Mg2+, Ca2+, Cr3+, Mn2+, Fe3+, Co2+, Co3+, Ni2+, Cu2+, Zn2+, Se2+, Mo6+, Ru4+, Rh3+, Pd2+, Ag+, Cd2+, Sn2+, Te2+, Te4+, Hg2+ and Pb2+ in natural samples using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) synchrotron radiation (Figure 1) and various analytical methods [1-21]. Pre–concentration methods generally improve sensitivity and selectivity of the analysis with the additional advantage of isolation the analyte from the interfering compounds [22,23]. In the recent years, Homogenous Liquid– Liquid Extraction (HLLE) using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) synchrotron radiation and various analytical methods has been extensively used in sample preparation due to speed, suitable performance, higher concentration factor and less solvent consumption in comparison with Liquid–Liquid Extraction (LLE) and Solid Phase Extraction (SPE) [24-44]. In the present editorial, an effective method is presented for pre–concentration of Mg2+, Ca2+, Cr3+, Mn2+, Fe3+, Co2+, Co3+, Ni2+, Cu2+, Zn2+, Se2+, Mo6+, Ru4+, Rh3+, Pd2+, Ag+, Cd2+, Sn2+, Te2+, Te4+, Hg2+ and Pb2+ by Homogenous Liquid–Liquid Extraction (HLLE) and using molecular beam mass spectrometry with tunable Vacuum Ultraviolet (VUV) Synchrotron radiation and various analytical methods.
关键词： Separation,Pre–Concentration,Vacuum Ultraviolet (VUV) Synchrotron Radiation,Molecular Beam Mass Spectrometry,DNA/RNA Chelates,Metal Cations,Analytical Methods
更新于2025-09-04 15:30:14
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Generating highly specific spectra and identifying thermal decomposition products via Gas Chromatography / Vacuum Ultraviolet Spectroscopy (GC/VUV): Application to nitrate ester explosives
摘要： Gas chromatography/mass spectrometry (GC/MS) is a "workhorse" instrument for chemical analysis, but it can be limited in its ability to differentiate structurally similar compounds. The coupling of GC to vacuum ultraviolet (VUV) spectroscopy is a recently developed technique with the potential for increased detection specificity. To date, GC/VUV has been demonstrated in the analysis of volatile organic compounds, petroleum products, aroma compounds, pharmaceuticals, illegal drugs, and lipids. This paper is the first to report on the utility of GC/VUV for explosives analysis in general, and the first to report on thermal degradation within the VUV cell and its analytical utility. The general figures of merit and performance of GC/VUV were evaluated with authentic standards of nitrate ester explosives (e.g., nitroglycerine (NG), ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), and erythritol tetranitrate (ETN)). In addition, the explosive analytes were thermally degraded in the VUV cell, yielding reproducible, complex and characteristic mixtures of gas phase products (e.g., nitric oxide, carbon monoxide, and formaldehyde). The relative amounts of the degradation products were estimated via spectral subtraction of library spectra. Lastly, GC/VUV was used to analyze milligram quantities of intact and burned samples of double-base smokeless powders containing nitroglycerine, diphenylamine, ethyl centralite, and dibutylphthalate.
关键词： Thermal degradation,Nitrate ester explosives,Vacuum ultraviolet spectroscopy,Gas chromatography
更新于2025-09-04 15:30:14