A newly established double-aperture-lens (DAL) retarding-field analyzer is a simple and accurate electron-energy analyzer for evaluation of the electron-beam energy spread (ΔE) in the next-generation electron gun. In this study, we discussed the energy-filtering characteristics of DAL analyzer in comparison with a conventional single-aperture-lens (SAL) analyzer, using surface-charge calculations, electron-trajectory simulations, and DAL defocus experiments. We examined how the lateral beam offset (ΔR) affects the transmission and cutoff behavior, and the shape of differential spectra. While DAL behaves as an ideal high-pass filter for small offsets (ΔR≤2μm), providing an accurate ΔE, SAL exhibits a strong ΔR dependence of the effective cutoff energy, which broadens the differential spectrum and causes the apparent ΔE to increase with beam radius. For larger offsets, however, electrons entering the DAL that overcome the saddle-point barrier can be intercepted by the second aperture, producing low-pass-like attenuation on the high-energy side and narrowing the differential spectrum, which was also confirmed by experiments. These results show that the DAL improves robustness to incident-position variation of the electron beam only within a limited offset range, and that reliable ΔE metrology requires careful control of beam size and alignment.
This work performs fully relativistic calculations on the K-shell excited states of Be-like Mn21+ ion via the multi-configuration Dirac–Hartree–Fock (MCDHF) method combined with relativistic configuration interaction (RCI), using the GRASP2018 package. Systematic computations are implemented for typical K-shell excited configurations including 1s2s2nl, 1s2s2pnl, and 1s2p2nl (n≤3,l=s,p,d). Large-scale configuration state function expansions with an active orbital space up to n≤9 are adopted, fully accounting for Breit interaction and quantum electrodynamics (QED) corrections. In total, 2689 electric dipole (E1) transition parameters, including energy levels, wavelengths, transition probabilities, line strengths, and oscillator strengths are derived. An optimized uncertainty evaluation method combined with NIST grading standards is employed to assess the reliability of the present data. Most calculated spectral wavelengths exhibit relative deviations within 0.08% compared with previously reported theoretical results, confirming the high precision and good numerical convergence of the present dataset. By comparative investigations of E1 transition parameters between Be-like Sc17+ and Mn21+ ions, we reveal distinct behaviours of QED and Breit relativistic corrections, enhancement in configuration mixing induced by spin–orbit coupling, as well as the finding that intensified configuration mixing does not necessarily degrade the computational precision of configuration-interaction calculations. This work constructs a self-consistent, high-precision atomic benchmark database for K-shell excited states of Mn21+ ions, fills the data deficiency in inner-shell excitation parameters for intermediate-Z Be-like ions, and provides accurate theoretical references for astrophysical spectral identification, fusion plasma diagnostic analysis, and radiative-collisional modelling.
Pure ZnO and Na-doped ZnO nanoparticles (Na = 1%, 3%, and 5%) have been synthesized by the simple co-precipitation method. XRD patterns and Rietveld refinement confirm the P63mc space group corresponding to the single-phase hexagonal wurtzite crystal structure of ZnO. SEM micrographs show a spherical particle structure with an average particle size of 40–60 nm in all prepared samples. XPS studies reveal the existence of defect-level states and oxygen vacancies (Vo’s) in all the synthesized samples; Vo’s increase with Na doping. UV-Visible spectroscopy indicates a decrease in the energy band gap from 3.23 eV to 3.19 eV with increasing Na concentration for Na-doped ZnO nanoparticles. The Photoluminescence spectroscopy results confirm the presence of defect-level emissions and lattice defects, including Vo’s, in all the prepared samples, and these increase with increasing Na doping. FTIR spectra confirm the presence of functional groups and chemical bonding at the ZnO interface. In the FTIR spectra, a weak absorption peak around 670 cm−1 confirms the presence of Na in the ZnO matrix, and the strong peak around 532 cm−1 indicates the formation of hexagonal wurtzite ZnO nanoparticles. VSM measurements show room-temperature ferromagnetism (RTFM) in all Na-doped ZnO nanoparticle samples. RTFM increases with enhancing Na-doping and increasing Vo’s, and a maximum saturation magnetization of 54.73 × 10−4 emu/gm was found in the 5% Na-doped ZnO sample. The origin of RTFM in the Na-doped ZnO system may be Vo’s and defects. The RTFM in the Na-doped ZnO system may be a suitable material for future spintronic applications.
X-Ray Photoelectron Spectroscopy (XPS) has been utilized to extract local electrical potential profiles by recording core level binding energy shifts upon application of a DC and/or AC [Square Wave (SQW)] bias at different frequencies. To carry out these measurements, co-planar capacitor devices with a polyethylene membrane (PEM) coated with Ionic Liquids (ILs); N,N-Diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI) and/or its 1:1 vol mixture with N,N-Diethyl-2-methoxy-N-methylethanaminium tetrafluoroborate (DEME-BF4) are constructed. Analyses were carried out in-operando; such that XPS measurements were performed simultaneously with current and Electrochemical Impedance (EIS) measurements under UHV environment. ILs have complex charging/discharging dynamics, and they induce formation of Electrical Double Layer (EDL) at the interface of the electrode. Certain properties of this process can be extracted via AC modulation under appropriate time windows. Herein, two frequencies, 10 kHz and 0.1 Hz, were selected to investigate the effects of fast polarization and slow migratory currents, respectively. Local electrical potential developments were extracted at different locations on the device, from the variations in binding energies before and after adding two equivalent resistors in series to the device in three different configurations. This modification of the circuit allowed us to quantify the AC currents passing through the device, as well as the system’s resistance and capacitance under specific conditions. Moreover, majority of the resultant XPS data could be faithfully reproduced by the LT-Spice simulation software, which enabled us to construct realistic equivalent circuit models of the electrochemical systems investigated. With this non-invasive nature of the methodology, XPS becomes a useful tool for extracting localized electrochemical information and may be of great importance in better understanding of energy harvesting and storage systems.
