- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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One-point calibration of Saha-Boltzmann plot to improve accuracy and precision of quantitative analysis using laser-induced breakdown spectroscopy
摘要： Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) has recently gained attention due to its potential to overcome matrix effects on quantitative analysis using LIBS. However, the efficiency of CF-LIBS may be compromised by uncertainties in the experimental and spectroscopic parameters. To minimize these uncertainties and improve quantitative analysis, the one-point calibration (OPC) method was recently introduced to empirically correct the emission line intensities in a Boltzmann plot. In this work, we used the OPC method on a Saha-Boltzmann plot to cover a large energy range and to obtain more precise and accurate plasma temperature and electron density (Ne) values than were obtained with a Boltzmann plot using OPC method. For the analysis, we prepared two sets of sodium chloride (NaCl) samples: one with graphite and another with calcium carbonate (CaCO3). We observed matrix effects when we evaluated the calibration curves of carbon line intensity as a function of carbon concentration. Corrections by the OPC method to the Boltzmann or Saha-Boltzmann plots minimized the matrix effects and also guaranteed that the calculated plasma temperature were the same for the primary elements of each sample, suggesting that they were in local thermodynamic equilibrium. When the OPC method was applied to the Saha-Boltzmann plot, we obtained an uncertainty of less than 0.5% for plasma temperature and Ne; an r2 value of 0.994; and a root mean square relative error (RMSRE) of 8% for C concentration. Meanwhile, the traditional OPC method resulted in an uncertainty of 2.3% for plasma temperature and Ne and a validation with r2 of 0.977 and RMSRE of 13% for C concentration. These results showed that the OPC method efficiently improved the quantitative analyses possible with the Saha-Boltzmann plot using CF-LIBS.
关键词： LIBS,Calibration-free model,One-point calibration,Electron density,Plasma temperature,Saha-Boltzmann plot
更新于2025-09-12 10:27:22
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Single shot high bandwidth laser plasma probe
摘要： A novel scheme to probe a plasma’s ion acoustic resonances in single shot high-bandwidth pump-probe experiments is proposed. Our design utilizes concepts similar to smoothing by spectral dispersion; however, we propose a method of applying the bandwidth to the probe that avoids the effects of angular dispersion. Theoretical modeling and ?uid simulations of the interaction are presented and compared. The results show the possibility of recovering a plasma’s full complex index of refraction in a single shot pump-probe experiment. This wavelength dependent refractive index is directly related to the plasma’s particle distribution function and can be used to recover plasma parameters including electron and ion temperatures, electron density, and plasma ?ow velocity.
关键词： electron density,plasma,refractive index,high-bandwidth,plasma flow velocity,ion acoustic resonances,pump-probe experiments
更新于2025-09-11 14:15:04
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Independent excitation of inhomogeneous energy density driven instability by electron density gradient
摘要： In this work, we report an experimental observation of the inhomogeneous energy density driven instability (IEDDI) independently excited by the electron density gradient. This was achieved using a novel design which could generate a controllable electron density gradient, while the self-consistent electric ?eld accompanied with the electron density gradient can be simultaneously compensated. Broadband wave mode in the ion cyclotron frequency range was excited, which was further experimentally identi?ed as the IEDDI. This result suggests that the IEDDI can be independently excited by the electron density gradient, which could be extended to explain the satellite observations of the broadband extremely low frequency waves in the auroral plasmas where the strong plasma density inhomogeneities exist.
关键词： IEDDI,auroral plasmas,ion cyclotron frequency,electron density gradient,broadband wave mode
更新于2025-09-10 09:29:36
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Investigation on the dynamic characteristics of LIBS for heavy metal Mn in liquid matrix
摘要： Laser-induced breakdown spectroscopy in composition analysis of materials has many advantages over other analytical methods.Based on our Laser Induced Breakdown Spectroscopy (LIBS) survey system of heavy metals in the mixed solution and the optimum experimental parameters, we measured the integrated intensities of partial spectral lines of Mn when the ICCD gate delay time and the sample ?ow rate were ranged from 500ns to 2500ns, 35ml/min to 55ml/min respectively. With increasing the time delay, the electron temperature of the plasma decreases gradually, the electron density decreases ?rstly,then the change amplitude tends to be ?at.As the ?ow rate continue increasing,the electron temperature of plasma increases ?rstly, then the change tends to be ?at, the electron density increase gradually.The element particle density ratio of Mn at ?rst ionization state to ground state and Mn at ?rst ionization state are also obtained respectively. Finally, by comparing the experimental value of spectral line intensity ratio of Mn with the calculated value, the nonexistent conditions of local thermal equilibrium and self-absorption of laser plasma are veri?ed.It provides the suppuration for forward quantitative analysis of the trace heavy metal elements in liquid matrix.
关键词： Liquid matrix,Laser induced breakdown spectroscopy,Elements particle density ratio,Electron temperature,Electron density
更新于2025-09-09 09:28:46
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Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging
摘要： In an electron beam ion trap (EBIT), the ions are not con?ned to the electron beam, but rather oscillate in and out of the beam. As a result, the ions do not continuously experience the full density of the electron beam. To determine the effective electron density, ne,eff, experienced by the ions, the electron beam size, the nominal electron density ne, and the ion distribution around the beam, i.e., the so-called ion cloud, must be measured. We use imaging techniques in the extreme ultraviolet (EUV) and optical to determine these. The electron beam width is measured using 3d → 3p emission from Fe xii and xiii between 185 and 205 ?. These transitions are fast and the EUV emission occurs only within the electron beam. The measured spatial emission pro?le and variable electron current yield a nominal electron density range of ne ～ 1011–1013 cm?3. We determine the size of the ion cloud using optical emission from metastable levels of ions with radiative lifetimes longer than the ion orbital periods. The resulting emission maps out the spatial distribution of the ion cloud. We ?nd a typical electron beam radius of ～60 μm and an ion cloud radius of ～300 μm. These yield a spatially averaged effective electron density, ne,eff, experienced by the ions in EBIT spanning ～ 5 × 109–5 × 1011 cm?3.
关键词： optical imaging,effective electron density,extreme ultraviolet spectra,electron beam ion trap,Fe xiv,Fe xiii,Fe xii
更新于2025-09-09 09:28:46
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A TUNABLE ELECTROMAGNETIC BANDGAP STRUCTURE USING PLASMA
摘要： A tunable electromagnetic-bangap (EBG) structure based on a double layer slotline using plasma is proposed. The plasma permittivity can be tuned by the electron density. The idea of integrating periodical plasma elements inside the slot to tune the stopband is investigated. An electron density and an electron collision frequency equal to 1.75 1013 cm?3 and 1010 s?1 respectively, are the plasma parameters selected in this study. The simulations reveal a shift rate of the second stopband equal to 6%. A new con?guration of the structure is also proposed to adapt it better to the experimental requirements. Based on the simulation results, adding the plasma elements to the modi?ed con?guration shifts the stopband 4% and reduces its bandwidth by 43% (at ?20 dB).
关键词： electron density,slotline,plasma,tunable electromagnetic bandgap,electron collision frequency,stopband
更新于2025-09-09 09:28:46
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Optical emission spectroscopy investigation of the current sheet in a small-bore parallel-plate electromagnetic plasma accelerator
摘要： The optical emission spectrum of the propagating current sheet in a small-bore parallel-plate electromagnetic plasma accelerator has been studied. The accelerator is powered by a fourteen stage pulse forming network, which yields a damped oscillation square wave of current with a pulse width of 20.5 ls. The movement of the first current sheet and the second current sheet is identified using three single magnetic probes placed at various axial positions. Current sheet canting is measured by two double magnetic probes. The spectrum of the current sheet is measured using a spectroscopic system. The electron density of the current sheet plasma is determined via Stark broadening of the hydrogen Ha line. The current sheet is almost perpendicular to the electrode. The current sheet electron density increases as the current sheet propagates. The current sheet electron density is mainly determined by the prefill pressure rather than the discharge current. The impurity charged particles caused by ablation of the back wall insulator exists in the current sheet. Residual particles are generally left behind the first current sheet and are swept and ionized by the second current sheet. The estimated current sheet sweeping efficiency is greater than 80%. The parallel-plate electromagnetic plasma accelerator developed in this paper shows great potential in generating high electron density plasma jets.
关键词： Stark broadening,optical emission spectroscopy,parallel-plate electromagnetic plasma accelerator,current sheet,electron density
更新于2025-09-09 09:28:46
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ASAXS study of CaF <sub/>2</sub> nanoparticles embedded in a silicate glass matrix
摘要： The formation and growth of nanosized CaF2 crystallites by heat treatment of an oxyfluoride glass of composition 7.65Na2O–7.69K2O–10.58CaO–12.5CaF2–5.77Al2O3–55.8SiO2 (wt%) was investigated using anomalous small-angle X-ray scattering (ASAXS). A recently developed vacuum version of the hybrid pixel detector Pilatus 1M was used for the ASAXS measurements below the Ca K-edge of 4038 eV down to 3800 eV. ASAXS investigation allows the determination of structural parameters such as size and size distribution of nanoparticles and characterizes the spatial distribution of the resonant element, Ca. The method reveals quantitatively that the growing CaF2 crystallites are surrounded by a shell of lower electron density. This depletion shell of growing thickness hinders and finally limits the growth of CaF2 crystallites. Moreover, in samples that were annealed for 10 h and more, additional very small heterogeneities (1.6 nm diameter) were found.
关键词： silicate glass matrix,electron density,CaF2 nanoparticles,ASAXS,nanostructure
更新于2025-09-09 09:28:46
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Design of a real-time two-color interferometer for MAST Upgrade
摘要： A single chord two-color CO2/HeNe (10.6/0.633 μm) heterodyne laser interferometer has been designed to measure the line integral electron density along the mid-plane of the MAST Upgrade tokamak, with a typical error of 1 × 1018 m?3 (～2? phase error) at 4 MHz temporal resolution. To ensure this diagnostic system can be restored from any failures without stopping MAST Upgrade operations, it has been located outside of the machine area. The ?nal design and initial testing of this system, including details of the optics, vibration isolation, and a novel phase detection scheme are discussed in this paper.
关键词： electron density,phase detection,MAST Upgrade,vibration isolation,two-color interferometer
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Measurement of total electronic cross-section, total atomic cross-section, effective atomic numbers and effective electron densities for some Sm compounds
摘要： Total electronic cross-section, total atomic cross-section, effective atomic number, and effective electron density were determined experimentally and theoretically for Sm2O3, SmI2, and SmCl3 compounds. The mass attenuation coefficient and total atomic cross section were calculated experimental values for Sm2O3, SmI2, and SmCl3 compounds. Theoretical mass attenuation coefficient values were computed from the XCOM data program. Exciting Sm compounds were measured using a Si(Li) detector with γ photons at 59.543 keV from 241 Am annular source. We have performed the measurements for the calculations of these values in attenuation and direct excitation experimental geometry. The effective atomic number and electron density for Sm compounds are being reported here for the first time.
关键词： effective atomic number,X-ray fluorescence,electron density,mass attenuation coefficient
更新于2025-09-04 15:30:14