Multi-line Calibration Research Articles

One-Point and Multiline Calibration Fiber-Optic Laser-Ablation Spark-Induced Breakdown Spectroscopy for Quantitative Analysis of Elements in Aluminum Alloys

Rapid and accurate analysis of element concentrations in aluminum alloys is crucial due to their widespread use in modern industry. This paper proposes a one-point and multiline calibration fiber-optic laser-ablation spark-induced breakdown spectroscopy (OP-MLC FO-LA-SIBS) for the quantitative analysis of elements in aluminum alloys. The experimental system utilizes a compact fiber laser as the laser-ablation source and spark discharge to enhance the atomic emission. A portable multichannel fiber spectrometer is used to quickly collect spectra in the nongated mode. The concentrations of four elements (Mg, Cr, Cu, and Mn) in four aluminum alloy samples were calculated using the simple and efficient OP-MLC method, which involves taking another sample with a similar matrix as the standard sample. The average relative errors (AREs) for Mg, Cr, Cu, and Mn were 6.38%, 28.09%, 21.92%, and 18.97%, respectively. When the certified concentrations are greater than 0.02 wt.%, the ARE is only 13.04%. The OP-MLC FO-LA-SIBS system is compact, features simple spectra processing, and offers effective measurement, providing a convenient method for rapid and efficient quantitative analysis of elements in aluminum alloys in industrial production.

Propagation Constant Measurement Based on a Single Transmission Line Standard Using a Two-Port VNA.

This study presents a new method for measuring the propagation constant of transmission lines using a single line standard and without prior calibration of a two-port vector network analyzer (VNA). The method provides accurate results by emulating multiple line standards of the multiline calibration method. Each line standard was realized by sweeping an unknown network along a transmission line. The network need not be symmetric or reciprocal, but must exhibit both transmission and reflection. We performed measurements using a slab coaxial airline and repeated the measurements on three different VNAs. The measured propagation constant of the slab coaxial airline from all VNAs was nearly identical. By avoiding disconnecting or moving the cables, the proposed method eliminates errors related to the repeatability of connectors, resulting in improved broadband traceability to SI units.

Validation of the Reference Impedance in Multiline Calibration With Stepped Impedance Standards

Validation of the Reference Impedance in Multiline Calibration With Stepped Impedance Standards

Application of quantitative analysis for aluminum alloy in femtosecond laser-ablation spark-induced breakdown spectroscopy using one-point and multi-line calibration

To achieve the quantitative elemental analysis of aluminum alloy samples, the one-point and multi-line calibration (OP-MLC) method and femtosecond laser-ablation spark-induced breakdown spectroscopy (fs-LA-SIBS) were combined in this study. An ultrafast Ti: sapphire laser with high single-pulse energy and high repetition–rate operation was used as the laser source to ablate the sample at a 1k Hz pulse repetition rate and achieve re-excitation using spark discharge. Subsequently, an enhanced spectral peak intensity was achieved, which increased the sensitivity and analytical capabilities of laser-induced breakdown spectroscopy (LIBS) technique. Considering only one confirmed sample, the OP-MLC method was used to calculate the concentration ratios of trace elements Mg, Cr, Cu, Mn and Zn in four aluminum alloy samples to the calibration samples by the integral intensity ratio of the elemental characteristic lines between the two samples. The average relative errors with the identified concentrations were 3.99%, 15.13%, 8.76%, 9.30% and 9.64%, respectively. The results showed that the combination of OP-MLC method and fs-LA-SIBS has good accuracy in the quantitative analysis of elements, and has the advantages of simplicity, rapidity and high sensitivity.

Calibration Strategies Applied to Laser-Induced Breakdown Spectroscopy: A Critical Review of Advances and Challenges

Over the years, laser-induced breakdown spectroscopy (LIBS) has been reported in the literature as an alternative to traditional methods of analysis, becoming well established among spectroanalytical techniques. LIBS is a technique widely used for qualitative approaches; however, it is necessary considerable effort for use in quantitative analysis, mainly due to severe matrix effects. These limitations make it difficult to broaden the application of LIBS in quantitative analysis. In this sense, this review discusses recent advances in calibration strategies applied in LIBS for minimizing matrix effects and enabling determination with satisfactory accuracy and precision. Applications, advantages, and limitations of the calibration strategies, such as matrix-matching calibration (MMC), internal standardization (IS), standard addition (SA), multi-energy calibration (MEC), one-point gravimetric standard addition (OP GSA), one-point and multi-line calibration (OP MLC), slope ratio calibration (SRC), two-point calibration transfer (TP CT), single-sample calibration (SSC), multiple linear regression (MLR), principal component regression (PCR), partial least squares (PLS) and artificial neural networks (ANN) are discussed.

Direct determination of Al and Pb in waste printed circuit boards (PCB) by laser-induced breakdown spectroscopy (LIBS): Evaluation of calibration strategies and economic - environmental questions

Matrix-matching calibration (MMC), two-point calibration transfer (TP CT), one-point and multi-line calibration (OP MLC), single-sample calibration (SSC) and calibration free (CF) were evaluated in order to overcome matrix effects in laser-induced breakdown spectroscopy (LIBS). These calibration strategies were evaluated for direct determination of Al and Pb in waste printed circuit boards (PCB) using direct solids analysis by LIBS. Each strategy has limitations and advantages of its implementation, for the correction of matrix effects, so that it allows elementary determination with adequate accuracy. The MMC and CF proved to be excellent calibration strategies for the determination of strategic (Al) and toxic (Pb) elements by LIBS, with good recoveries (ranging from 80–120%) and low relative standard deviation (RSD%) values. A detailed discussion of the advantages and limitations of each of these five calibration strategies evaluated for LIBS is presented in this study. Lead concentrations in waste PCB samples are 5–12 times higher than established by Directive 2011/65/EU, and the samples analyzed contain between 3 and 55 g kg−1 Al, being an interesting economic and recycling source for this metal.

Direct Determination of Ca, K, and Mg in Cocoa Beans by Laser-Induced Breakdown Spectroscopy (LIBS): Evaluation of Three Univariate Calibration Strategies for Matrix Matching

This study is dedicated to the direct analysis of Ca, K, and Mg by employing laser-induced breakdown spectroscopy (LIBS). Three univariate calibration strategies, namely (i) one-point and multi-line calibration (OP MLC), (ii) single-sample calibration (SSC), and (iii) two-point calibration transfer (TP CT), were evaluated and compared. Only OP MLC and TP CT presented precise and accurate results, where the trueness values ranged from 80 to 120% for most of the analyzed samples. Moreover, the standard errors for all determined elements ranged from 0.01 to less than 0.20% of the concentration in the samples. These three calibration strategies showed that they are efficient and effective for matrix matching to correct matrix effects in complex samples using only one sample as the standard.

One-point and multi-line calibration method in laser-induced breakdown spectroscopy.

The calibration-free laser-induced breakdown spectroscopy (CF-LIBS) and its variations are low cost, short time consumption, and high adaptability. However, seeking a more flexible and simple quantitative analysis method remains a challenge. A one-point and multi-line calibration (OP-MLC) was presented as a simple quantitative analysis method of LIBS. The results showed that OP-MLC-LIBS method can achieve quantitative analysis using only one standard sample, and the average relative errors (AREs) are 9, 22, 21 and 36% for Mn, Cr, Ni and Ti elements in six tested low-alloy steel samples, respectively. The method requires neither a large number of standard samples nor complicated calculations, which provides a flexible and low-cost quantitative analysis approach for development and application of LIBS.

On the Possibility of Reducing the Systematic and Random Errors of Atomic Emission Spectral Analysis Using Multiline Calibration

The main systematic and random errors of atomic emission spectral analysis and various procedures used for their reduction are considered: classical internal standard approach, non-spectral matrix effects, the use of several spectral lines of the analyte and internal standard with and without weight coefficients, signal drift, instability of sample injection and conditions of spectra excitation. The necessity of incorporating those methods into the software of the devices intended for atomic emission spectral analysis with various sources of spectrum excitation, including inductively coupled plasma is demonstrated. An algorithm and stand-alone program for optimization of the calibration curve based on multiline recording of the spectral lines of matrix elements and analyte, internal standards, solvent, and discharge atmosphere, capable of implementing the above methods of error reduction both in calibration and analysis are developed.

Calibration-Kit Design for Millimeter-Wave Silicon Integrated Circuits

We study and present design guidelines for thru-reflect-line vector-network-analyzer calibration kits used for characterizing circuits and transistors fabricated on silicon integrated circuits at millimeter-wave frequencies. We compare contact-pad designs and develop fixed-fill contacts that achieve both repeatable and low contact-pad capacitances. We develop a fill-free and mesh-free transmission line structure for the calibration kit and compare it to similar transmission lines with meshed ground plane. We also develop a gold plating process that greatly improves contact repeatability, permitting the use of redundant multiline calibrations. This in turn simplifies the development of an error analysis. Finally, we apply the technique to state-of-the-art transistor characterization, and present measured results with uncertainties.

Characterization of Differential Transmission Lines for Integrated Millimeter-Wave Applications

This letter focuses on the characterization of differential transmission lines (T-lines) typically used in millimeter-wave integrated circuits. Common- and differential-mode propagation constants were calculated and validated in two experimental steps. A four-port scattering parameter (S-parameter) measurement followed by a multi-line calibration was performed. In addition, several two-port S-parameter measurements were conducted using a set of three marchand baluns. Comparison of the values extracted from simulations and two experiments shows very good agreement over a broad frequency range from 65 to 170 GHz.

Processing and Dielectric Properties of Nanocomposite Thin Film “Supercapacitors” for High-Frequency Embedded Decoupling

The embedded decoupling capacitor problem has been pursued by several groups and industry around the world over the past decade. Currently, popular ceramic-polymer composites can only provide limited capacitance, typically within 10 nF/cm2 . With the reliability and processing constraints imposed, the capacitance density would be much lower. Newer capacitor concepts such as supercapacitors can overcome the limitations of existing polymer based capacitors and are now being considered. These concepts rely on nanostructured electrodes for high surface area per unit volume resulting in ultrahigh capacitance densities and unconventional polarization mechanisms such as electrical double layer and interfacial polarization. Supercapacitive structures lead to ultrahigh capacitance densities of the order of hundreds of microfarads. However, manufacturers report that the properties are unstable at high frequencies, typically even at tens of megahertz. To adapt these structures for mid-to-high-frequency decoupling, it is hence essential to systematically characterize the high-frequency dielectric properties of the thin nanocomposite films and nanostructured electrodes. This paper reports complete electrical characterization of a part of such a system, carbon black-epoxy nanocomposites. The high-frequency properties of the cured films were evaluated with a multiline calibration technique by measuring -parameters of transmission lines fabricated on the top of the dielectrics. Though the nanostructured carbon black epoxy composites showed high dielectric constant of 1000 at low frequencies, the high frequency (0.5-4.5GHz) dielectric constant was found to be only up to 10 times that of the base polymer matrix. The measured dielectric constant at gigahertz frequencies increased from 15-30 when the filler content was increased from 3.8% to 6.5%, with excessive leakage currents. Based on these measurements, conduction and polarization relaxation mechanisms will be assessed and the suitability of the thin film supercapacitors for high-frequency decoupling applications will be discussed.

Electronically tunable multi-line TRL usingan impedance matched multi-BitMEMS phase shifter

An electronically tunable thru-reflect-line (TRL) calibration set that utilizes a 4-b true time delay microelectromechanical systems (MEMS) phase shifter topology, based on impedance-matched slow-wave coplanar waveguide (CPW) sections, is presented. The accuracy of the tunable TRL is close to a conventional multi-line TRL calibration and shows a maximum error bound of 0.12 at 40GHz. Experimental data for a 4.6mm-long tunable delay standard shows 317/spl deg//dB phase shift at 50GHz (or 91/spl deg//mm) with S/sub 11/ less than -21dB from 1-50GHz. The MEMS beams on the phase shifter are actuated using high resistance SiCr bias lines with typical actuation voltage around 30-45V.

Some measurement results for frequency-dependent inductance of IC interconnects on a lossy silicon substrate

Frequency dependent measurements of scattering (S) parameters using a vector network analyzer (VNA) have been performed on IC interconnects on a lossy silicon substrate. The multiline calibration method has been used to perform the de-embedding of the line parameters, from which the line inductance is extracted. A highly accurate closed-form approximation for frequency-dependent impedance per unit length of a lossy silicon substrate for IC interconnects has been used to compare with the measurements performed.

Compact soft x-ray reflectometer based on a line-emitting laser-plasma source

We describe a compact soft x-ray reflectometer for in-house characterization of water-window multilayer optics. The instrument is based on a line-emitting, liquid-jet, laser-plasma source in combination with angular scanning of the studied multilayer optics. With a proper choice of target liquid and thin-film filters, one or a few lines of well-defined wavelength dominate the spectrum and multilayer periods are measured with an accuracy of 0.003 nm using a multi-line calibration procedure. Absolute reflectivity may also be estimated with the instrument. The typical measurement time is currently 10 min. Although the principles of the reflectometer may be used in the entire soft x-ray and extreme ultraviolet range, the current instrument is primarily directed towards normal-incidence multilayer optics for water-window x-ray microscopy, and is thus demonstrated on W/B4C multilayers for this wavelength range.

Contributions to accuracy improvement of simultaneous ICP atomic emission spectrometry using multi-line measurements of analyte and internal standard elements Applications for the analysis of permalloy

For successful application of simultaneous ICP atomic emission spectrometry for major component determinations in multi-component materials the accuracy of the method has to be improved. As a contribution to solve this problem a combined procedure for multi-component standard sample preparation, optimum calibration and different variations of internal standard corrections is described. Variance-weighted multi-line calibrations give most accurate results. Internal standard corrections are effective, if the time-dependent spectral line intensity fluctuations of the standard and the analyte elements are well correlated. Their sensitivities against some responsible device parameter variations are investigated. On the basis of multi-line measurements of the analyte and internal standard elements a “group-selected internal standard correction” (GS-ISC) method is applied and results in relative errors of less than 1% even for extreme fluctuations of the raw intensities. For rapid routine determination methods of materials with variable element compositions the added line intensities of the internal standard element can be used to correct the added analyte line raw intensities (“intensity addition internal standard correction” (IA-ISC) method). These accuracy optimization procedures are applied for the analysis of the soft magnetic material permalloy using the internal standard element In.

Gamma-ray emission probabilities of the daughters of 238U

A wealth of decay data has been obtained and reported in recent years, much of it in “Decay Data of the Transactinium Nuclides”. IAEA Technical Reports Series No. 261 (1986). The decay data for the daughters of 238U have been notable by their absence in such compilations and, since there is a need for such data, a set of experiments has been performed to measure their gamma-ray emission probabilities. Uranium samples of known mass and isotopic concentration were dissolved in aqueous solution, and analyzed with a high-purity germanium gamma-ray spectrometer. Some of these samples also contained multi-line calibration nuclides with well-known relative emission probabilities and the well-known emission probabilities of the 235U gamma rays were also used to provide an absolute emission probability reference. Since self-absorption of the sample was included in the effective detector efficiency, there was no need for a separate calculation of this absorption. Gamma-ray emission probabilities for the energy range 63 to 1937 keV are reported, and sources of error are discussed, including those in the efficiency curve.