Mass Calibration Research Articles

Online coupling of liquid chromatography and two-dimensional diffusion ordered spectroscopy for the analysis of oligostyrenes

The aim of this study was to introduce a powerful coupling of Liquid Adsorption Chromatography (LAC) and Diffusion-Ordered Spectroscopy (DOSY) for comprehensive structure analysis. This new hyphenation approach facilitated the simultaneous separation of a polymer mixture and the determination of molar masses within a single 3D experiment. The online coupling of High-Performance Liquid Chromatography (HPLC) and two-dimensional DOSY-NMR will be called 3D-LAC-NMR-DOSY experiment. Our methodology enabled the chromatographic separation of analytes based on their chemical heterogeneity, and provided accurate molar masses of the analytes through 2D-DOSY. This new method was demonstrated on a polystyrene oligomer mixture. In this case, the oligostyrenes could be separated with LAC according to their tacticity and chain length in protonated acetonitrile as eluent and DOSY measurements provided the molar masses of each oligomer. In order to show the power of the 3D-LAC-NMR-DOSY method, the comparison to 2D-DOSY, 3D-DOSY and LAC-NMR was separately evaluated. Furthermore, the recently published solvent-independent molar mass calibration of diffusion coefficients was also successfully applied in our LAC-DOSY studies for molar mass predictions of the oligomers in acetonitrile. The predicted molar masses were in good agreement with the LAC-DOSY measurements and were verified by calibrations of diffusion coefficients and mass spectrometry. Finally, this pioneering 3D technique offers a powerful new tool for advancing structure analysis and enhancing our understanding of complex systems such as oligostyrenes.

Blind Calibration of Environmental Acoustics Measurements Using Smartphones.

Environmental noise control is a major health and social issue. Numerous environmental policies require local authorities to draw up noise maps to establish an inventory of the noise environment and then propose action plans to improve its quality. In general, these maps are produced using numerical simulations, which may not be sufficiently representative, for example, concerning the temporal dynamics of noise levels. Acoustic sensor measurements are also insufficient in terms of spatial coverage. More recently, an alternative approach has been proposed, consisting of using citizens as data producers by using smartphones as tools of geo-localized acoustic measurement. However, a lack of calibration of smartphones can generate a significant bias in the results obtained. Against the classical metrological principle that would aim to calibrate any sensor beforehand for physical measurement, some have proposed mass calibration procedures called "blind calibration". The method is based on the crossing of sensors in the same area at the same time, which are therefore supposed to observe the same phenomenon (i.e., measure the same value). The multiple crossings of a large number of sensors at the scale of a territory and the analysis of the relationships between sensors allow for the calibration of the set of sensors. In this article, we propose to adapt a blind calibration method to data from the NoiseCapture smartphone application. The method's behavior is then tested on NoiseCapture datasets for which information on the calibration values of some smartphones is already available.

ACT-DR5 Sunyaev-Zel’dovich clusters: Weak lensing mass calibration with KiDS

We present Weak Gravitational Lensing measurements of a sample of 157 clusters within the Kilo Degree Survey (KiDS), detected with a > 5σ thermal Sunyaev-Zel’dovich (SZ) signal by the Atacama Cosmology Telescope (ACT). Using a halo-model approach, we constrained the average total cluster mass, MWL, accounting for the ACT cluster selection function of the full sample. We find that the SZ cluster mass estimate MSZ, which was calibrated using X-ray observations, is biased with MSZ/MWL = (1 − bSZ) = 0.65 ± 0.05. Separating the sample into six mass bins, we find no evidence of a strong mass dependency for the mass bias, (1 − bSZ). Adopting this ACT-KiDS SZ mass calibration would bring the Planck SZ cluster count into agreement with the counts expected from the Planck cosmic microwave background ΛCDM cosmological model, although it should be noted that the cluster sample considered in this work has a lower average mass MSZ, uncor = 3.64 × 1014 M⊙ compared to the Planck cluster sample which has an average mass in the range MSZ, uncor = (5.5 − 8.5)×1014 M⊙, depending on the sub-sample used.

Supplementary comparison SIM.M.FF-S9.2016 for water flow measurement

Main textThe objective of the Supplementary Comparison (SC) SIM.M.FF-S9 for water flow measurement was to support and prove the Calibration and Measurement Capabilities (CMC) of the participating NMIs of Chile (CISA), Peru (INACAL), Bolivia (IBMETRO) and Argentina (INTI). As pilot laboratories, the national metrology institutes of Germany (PTB) and CENAM (Mexico) supported the comparison with reference values. The comparison was organized as a single round robin, started in January 2016 at PTB and finished in August 2019, also at PTB. A combined setup of a turbine meter and Coriolis meter was used as a transfer standard. The nominal calibration conditions of the SC were defined in the flow range between 10 m3/h and 130 m3/h, 20 °C fluid temperature and 0.3 MPa line pressure. In order to estimate the uncertainties u TS, both transfer meters were subjected to extensive characterization measurements at pilot laboratory PTB. The following parameters were researched in detail: fluid temperature, line pressure, reproducibility, flow stability and meter sensitivity to different inflow conditions. The E N values for the turbine meter were calculated based on PTB data, only. The E N values for the Coriolis meter are partly linked to Key Comparison CCM.FF-K1.2015 and were calculated using a common reference value of PTB and CENAM data. The uncertainty of turbine meter u TS was clearly dominated by the sensitivity to disturbed inflow conditions which leads to large values of u TS with > 0.20 %. Beside one calibration, all labs passed the E N criteria of ≤ 1.20. But, due to large values of u TS, the calibrations for all labs were evaluated as inconclusive. The evaluation criteria u comp/u base exceeded the critical value of 2.00 for all calibrations. Finally, the turbine meter was not suitable for a confirmation of the submitted CMC values. The calibration results of the Coriolis meter were characterized by a strong dependency on zero setting. The observed effect was adjusted for the data of both reference laboratories by introducing a new method for autozero correction. Maximum uncertainty values for Coriolis u TS were estimated with 0.069 % at low flowrates and 0.033 % at high flowrates. Besides two calibrations, all laboratories complied with the E N criteria of ≤ 1.20. In contrast to turbine meter, the evaluation criteria u comp/u base exceeded the critical value of 2.00 at one calibration, only. In consequence, the calibrations by using the Coriolis meter were suitable for a confirmation of the submitted CMC values. In summary, the comparison was successfully finished for a confirmation of the submitted CMC values, related to mass calibrations. For volume related CMCs this comparison was not suitable.The comparison was partially financially supported by the German Federal Ministry for Economic Cooperation and Development (BMZ) - PNs: 2012.2296.7-95259, 2015.2037.8-95306 and 2017.2073.9-95328.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Ion emission from 1-10 MDa salt clusters: individual charge state resolution with charge detection mass spectrometry.

Salt cluster ions produced by electrospray ionization are used for mass calibration and fundamental investigations into cluster stability and charge separation processes. However, previous studies have been limited to relatively small clusters owing to the heterogeneity associated with large, multiply-charged clusters that leads to unresolved signals in conventional m/z spectra. Here, charge detection mass spectrometry is used to measure both the mass and charge distributions of positively charged clusters of KCl, CaCl2, and LaCl3 with masses between ∼1 and 10 MDa by dynamically measuring the energy per charge, m/z, charge, and mass of simultaneously trapped individual ions throughout a 1 s trapping time. The extent of remaining hydration on the clusters, determined from the change in the frequency of ion motion with time as a result of residual water loss, follows the order KCl < CaCl2 < LaCl3, and is significantly lower than that of a pure water nanodrop, consistent with tighter water binding to the more highly charged cations in these clusters. The number of ion emission events from these clusters also follows this same trend, indicating that water at the cluster surface facilitates charge loss. A new frequency-based method to determine the magnitude of the charge loss resulting from individual ion emission events clearly resolves losses of +1 and +2 ions. Achieving this individual charge state resolution for ion emission events is an important advance in obtaining information about the late stages of bare gaseous ions formation. Future experiments on more hydrated clusters are expected to lead to a better understanding of ion formation in electrospray ionization.

Projection effects on pressure profiles: A case study of the Virgo replica

An accurate mass calibration of galaxy clusters is a crucial step towards precise constraints on the cosmological parameters σ8 and Ωm from clusters. Cluster masses can be estimated assuming hydrostatic equilibrium, but several physical and observational effects can alter this calculation. One of those are projection effects which are the focus of our present analysis. We present a case study of the simulated Virgo cluster, extracted from the CLONE constrained simulation. We study Virgo pressure and electron density quantities projected along different directions, including along the Milky Way-Virgo axis which mimics our observation direction. We show two main projection effects: the role of the integrated mass along the line of sight (LoS) in each chosen direction, including the presence of massive objects, and the signature of small scale physics in the core of the cluster along these directions.

Microgravity Decoupling in Torsion Pendulum for Enhanced Micro-Newton Thrust Measurement

To enhance the accuracy of micro-Newton thrust measurements via a torsion pendulum, addressing microgravity coupling effects caused by platform tilt and pendulum mass eccentricity is crucial. This study focuses on analyzing and minimizing these effects by alleviating reference surface tilt and calibrating the center of mass during thrust measurements. The study introduced analysis techniques and compensation measures. It first examined the impact of reference tilt and center of mass eccentricity on the stiffness and compliance of the torsion pendulum by reconstructing its dynamic model. Simscape Multibody was initially employed for numerical analysis to assess the dynamic coupling effects of the tilted pendulum. The results showed the influence of reference tilt on the stiffness and compliance of the torsion pendulum through simulation. An inverted pendulum was developed to amplify the platform’s tilt angle for microgravity drag-free control. Center of mass calibration can identify the gravity coupling caused by the center of mass position. Based on the displacement signal from the capacitive sensor located at the end of the inverted pendulum, which represents the platform’s tilt angle, the pendulum’s vibration at 0.1 mHz was reduced from 5.7 μm/Hz1/2 to 0.28 μm/Hz1/2 by adjusting the voltage of piezoelectric actuator. Finally, a new two-stage torsion pendulum structure was proposed to decouple the tilt coupling buried in both pitch and roll angle. The study utilized theoretical models, numerical analysis, and experimental testing to validate the analysis methods and compensation measures for microgravity coupling effects in torsion pendulums. This led to a reduction in low-frequency noise caused by ground vibrations and thermal strains, ultimately improving the micro-Newton thrust measurement accuracy of the torsion pendulum through the platform’s drag-free control.

Top quark mass calibration for Monte Carlo event generators — an update

We generalize and update our former top quark mass calibration framework for Monte Carlo (MC) event generators based on the e+e− hadron-level 2-jettiness τ2 distribution in the resonance region for boosted tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document} production, that was used to relate the Pythia 8.205 top mass parameter mtMC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MC}} $$\\end{document} to the MSR mass mtMSRR\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MSR}}(R) $$\\end{document} and the pole mass mtpole\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{pole}} $$\\end{document}. The current most precise direct top mass measurements specifically determine mtMC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MC}} $$\\end{document}. The updated framework includes the addition of the shape variables sum of jet masses τs and modified jet mass τm, and the treatment of two more gap subtraction schemes to remove the O\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ \\mathcal{O} $$\\end{document}(ΛQCD) renormalon related to large-angle soft radiation. These generalizations entail implementing a more versatile shape-function fit procedure and accounting for a certain type of (mt/Q)2 power corrections to achieve gap-scheme and observable independent results. The theoretical description employs boosted heavy-quark effective theory (bHQET) at next-to-next-to-logarithmic order (N2LL), matched to soft-collinear effective theory (SCET) at N2LL and full QCD at next-to-leading order (NLO), and includes the dominant top width effects. Furthermore, the software framework has been modernized to use standard file and event record formats. We update the top mass calibration results by applying the new framework to Pythia 8.305, Herwig 7.2 and Sherpa 2.2.11. Even though the hadron-level resonance positions produced by the three generators differ significantly for the same top mass parameter mtMC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MC}} $$\\end{document} value, the calibration shows that these differences arise from the hadronization modeling. Indeed, we find that mtMC\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MC}} $$\\end{document} agrees with mtMSR\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {m}_t^{\ extrm{MSR}} $$\\end{document}(1 GeV) within 200 MeV for the three generators and differs from the pole mass by 350 to 600 MeV.

The Universal Calibration for Structure- and Solvent-Independent Molar Mass Determinations of Polymers Using Diffusion-Ordered Spectroscopy.

It will be shown how diffusion-ordered spectroscopy (DOSY) can produce a universal calibration of molar mass dependences of polymers compared to size exclusion chromatography (SEC) or recently published DOSY methods. Whereas SEC can deliver only structure-independent universal calibrations for a particular solvent, DOSY was used for creating solvent-independent calibrations for a certain polymer. Now, we can demonstrate a universal calibration method that generates both a structure- and solvent-independent molar mass calibration. Only one mathematical function describes the structure- and solvent-independent calibrations for DOSY by implementing the Mark-Houwink approach. The derived equation is tested on polystyrene (PS), poly(ethylene oxide), and poly(methyl methacrylate) of different molar masses and in different solvents. Altogether, 94 diffusion coefficients representing 16 molar mass calibrations of the diffusion coefficients in 10 different solvents could be perfectly matched to one universal calibration function with an average deviation of just 2.5%. It was also found that the Mark-Houwink parameters calculated by DOSY are very close to the SEC data. In any case, this new approach is a very useful tool for the determination of molar masses and new Mark-Houwink parameters via DOSY.

Modeling Known Sources of Mass Calibration Deviations in High Resolution ToF MS.

Modern time-of-flight mass spectrometer instruments exhibit excellent mass accuracy in the parts per billion range. At this level, mass calibration methods should consider potential distortions in the basic calibration. Factors which can cause distortions are to be under control. We have analytically modeled and numerically verified the influence of the main causes of mass calibration distortions, including the uncompensated dependence of flight time on the starting position, spatial gradient of the accelerating field, and overshooting at the rising edge of the accelerating pulse. Additionally, the relativity correction has been taken into account.

Methods for Calibrating the Electrochemical Quartz Crystal Microbalance: Frequency to Mass and Compensation for Viscous Load

The main output from an Electrochemical Quartz Crystal Microbalance is a frequency shift. This note describes how to separate the mass- and viscous load contributions to this shift by a calibration procedure. The mass calibration is made by electroplating from a copper sulfate solution in ethanol/water with 100% current efficiency. An estimate of viscous load is obtained by measuring the energy dissipation and is related to frequency change using the Kanazawa–Gordon equation. Two approaches are discussed: either by performing calibration experiments in a series of water–glycerol mixtures or by following oscillations in frequency and dissipation by collecting data during the stabilization phase of the experiment.

Improving mass accuracy in matrix-assisted laser desorption ionization time-of-flight mass spectrometry analysis of pathogenic proteins using 6xHIS-tagged internal calibration.

Linear mode of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been routinely used for bacterial identification in the clinic, depending on the pattern analysis of spectral libraries rather than accurate mass measurement of ribosomal proteins (10-15 kDa). However, a demand for more accurate mass analysis of pathogens (e.g. KPC-2 carbapenemase) has been recently increasing for diagnostic purposes. We introduced a 6xHIS-tagged KPC-2 (i.e. hKPC-2) and used it as an internal mass calibrator for the mass calibration of target proteins. After internal mass calibration (In-Cal), we evaluated the observed mass of KPC-2 against the theoretical mass of hKPC-2, which has 823 Da mass difference from the target protein. We further assessed the accuracy and precision of our calibration method regarding the identification of KPC-2 and other pathogens in clinical isolates (n = 42). Among several candidates for internal mass calibrators, the In-Cal using a 6xHIS-tagged protein on the target showed the highest mass accuracy and precision in the detection of target proteins (e.g. KPC-2). The application of hKPC-2 as an internal calibrator showed substantial improvement of mass accuracy, mass precision and also quantification of KPC in linearity and repeatability for KPC detection in the clinical isolates. Our In-Cal method using 6xHIS-tagged protein in MALDI-TOFMS allows successful mass calibration (<3.5Da) of pathogenic proteins (>20 kDa) and provides high mass accuracy as much as that of medium- and high-resolution mass spectrometry.

Enabling one- and two-dimensional mass spectrometry in a linear quadrupole ion trap

Two-dimensional tandem mass spectrometry (2D-MS/MS) provides rapid unsupervised access to all product ions of all ionized precursor ions in a single scan, and as such, is a powerful analysis method for quadrupole ion traps. However, the way in which 2D-MS/MS was previously implemented on our Thermo LTQ prevented us from switching back and forth from conventional one-dimensional mass spectrometry (1D-MS) without significant effort and on any reasonable timescale. This drawback inhibited our ability to perform standard workflows such as mass calibration and automatic voltage optimizations, but also made it impractical to perform cross-validation between modes on the same instrument. In effect, this reduced our data quality, preventing us from generating 2D-MS/MS spectral libraries with high fidelity, and from comparing spectra collected under differing conditions (user, time, etc.). In this study, an Arduino Uno microcontroller is used to control several electrical/electromechanical switches and the timing of all experimental subsystems in response to the instrument trigger output and a user selected operating mode. With a selection made, the user simply needs to adjust a few software parameters and change the bath gas of the linear ion trap. The ability to rapidly switch operational modes is demonstrated using a mixture of tetraalkylammonium cations for which spectra are collected in both 1D (helium) and 2D (nitrogen) modes in less than 1 min. By calibrating and measuring the RF amplitude control signal in 1D mode it is possible to calculate the applied RF amplitude in 2D mode, thereby allowing the user to determine relevant quadrupole operating parameters for a particular sample. Details of the system and its modifications are provided.

Dependency of high-mass satellite galaxy abundance on cosmology in Magneticum simulations

Context. Observational studies carried out to calibrate the masses of galaxy clusters often use mass–richness relations to interpret galaxy number counts. Aims. Here, we aim to study the impact of the richness–mass relation modelled with cosmological parameters on mock mass calibrations. Methods. We build a Gaussian process regression emulator of high-mass satellite abundance normalisation and log-slope based on cosmological parameters Ωm, Ωb, σ8, h0, and redshift z. We train our emulator using Magneticum hydrodynamic simulations that span different cosmologies for a given set of feedback scheme parameters. Results. We find that the normalisation depends, albeit weakly, on cosmological parameters, especially on Ωm and Ωb, and that their inclusion in mock observations increases the constraining power of these latter by 10%. On the other hand, the log-slope is ≈1 in every setup, and the emulator does not predict it with significant accuracy. We also show that satellite abundance cosmology dependency differs between full-physics simulations, dark-matter only, and non-radiative simulations. Conclusions. Mass-calibration studies would benefit from modelling of the mass–richness relations with cosmological parameters, especially if the satellite abundance cosmology dependency.

Intensity-dependent mass search for improving metabolite database matches in chemical isotope labeling LC-QTOF-MS-based metabolomics

Liquid chromatography mass spectrometry (LC-MS) has been increasingly used for metabolome analysis. One of the critical steps in the LC-MS metabolome analysis workflow is related to metabolite identification. Among the measured parameters, peak mass is commonly used to search against a database for potential metabolite matches. Higher accuracy mass measurement allows the use of a narrower mass tolerance window for mass search. While various types of mass analyzers can routinely measure a peak mass with an error of less than a few ppm, mass measurement accuracy is not uniform for peaks with different intensities, particularly for quadrupole time-of-flight (QTOF) MS. Herein we present a simple and convenient method to determine the relation between peak intensity and mass error in LC-QTOF-MS-based metabolome analysis, followed by intensity-dependent mass search (IDMS) of a database for metabolite matches. This method is based on running a series of sodium formate mass calibrants, as part of the standard operating procedure (SOP) in LC-MS data acquisition, and then curve-fitting the measured mass errors and peak intensities. We show that, in two different quadrupole time-of-flight (QTOF) mass analyzers, mass accuracy is generally reduced as peak intensity decreases, which is independent of m/z values in the range commonly used for metabolite detection (e.g., m/z < 1000). We demonstrate the improvement in metabolite matches using IDMS in the analyses of dansyl labeled standards and human urine samples. We have implemented the IDMS method in the freely available MCID database at www.mycompoundid.org, which is composed of 8021 known human endogenous metabolites and their predicted metabolic products (375,809 compounds from one metabolic reaction and 10,583,901 compounds from two reactions).

Neural network algorithm enables mass calibration autocorrection for miniature mass spectrometry systems

Mass spectrometry (MS) is a powerful analytical technology widely used in a broad range of applications. Laboratory-scale mass spectrometers, however, are hardly used outside the analytical laboratories due to the large sizes and weights. Miniature mass spectrometers are therefore developed to facilitate on-site MS analysis. How to stabilize their analytical performances under complex environmental conditions on-site is a challenging problem, which needs to be addressed for the development of miniature MS instrumentation. Here, we report a neural network algorithm which enables automatic mass calibration corrections for a Cell miniature MS system (PURSPEC Technologies Inc.). To simulate the change of complex environmental conditions on-site, variations of temperature from 5 °C to 40 °C, pressure from 98647 Pa to 99406 Pa, humidity from 30 % to 65 %, were employed. The mass accuracy, characterized by the difference between measured mass and nominal mass, after autocorrection of the algorithm was within 0.08 Da.

Isotopic and elemental analysis by electrostatic energy analyzer laser ablated time-of-flight mass spectrometer

In this work, we present a modified setup of the time of flight (TOF) mass spectrometer. It consists of a laser ablation source, and a Q-switched Nd:YAG laser (532 nm, 100 mJ, 7 ns) integrated with a linear TOF mass spectrometer coupled with an electrostatic energy analyzer (EEA). Ions are detected by a channeltron electron multiplier assembled with EEA. The main objective of this work is to resolve the ion’s initial energy problem and improve the reproducibility of the results. Employing this newly developed setup the elemental analysis of a known sample was performed for different laser energies and found no shift in the position of the ions signals on the time scale. In addition to elemental analysis, isotopic compositions of lithium, titanium, copper, and silver samples have been also derived. Our results are in good agreement with their natural abundance. The design parameters of the instrument were optimized. The mass calibration was achieved by measuring the flight time of various ions; Li+, Ti+, Cu+, and Ag+.

Star formation rate and stellar mass calibrations based on infrared photometry and their dependence on stellar population age and extinction

Context. The stellar mass (M⋆) and the star formation rate (SFR) are among the most important features that characterize galaxies. Measuring these fundamental properties accurately is critical for understanding the present state of galaxies, their history, and future evolution. Infrared (IR) photometry is widely used to measure the M⋆ and SFR of galaxies because the near-IR traces the continuum emission of the majority of their stellar populations (SPs), and the mid/far-IR traces the dust emission powered by star-forming activity. Aims. This work explores the dependence of the IR emission of galaxies on their extinction, and the age of their SPs. It aims to provide accurate and precise IR-photometry SFR and M⋆ calibrations that account for SP age and extinction while providing quantification of their scatter. Methods. We used the CIGALE spectral energy distribution (SED) fitting code to create model SEDs of galaxies with a wide range of star formation histories, dust content, and interstellar medium properties. We fit the relations between M⋆ and SFR with IR and optical photometry of the model-galaxy SEDs with the Markov chain Monte Carlo (MCMC) method. As an independent confirmation of the MCMC fitting method, we performed a machine-learning random forest (RF) analysis on the same data set. The RF model yields similar results to the MCMC fits, thus validating the latter. Results. This work provides calibrations for the SFR using a combination of the WISE bands 1 and 3, or the JWST NIR-F200W and MIRI-F2100W. It also provides mass-to-light ratio calibrations based on the WISE band-1, the JWST NIR-F200W, and the optical u − r or g − r colors. These calibrations account for the biases attributed to the SP age, while they are given in the form of extinction-dependent and extinction-independent relations. Conclusions. The proposed calibrations show robust estimations while minimizing the scatter and biases throughout a wide range of SFRs and stellar masses. The SFR calibration offers better results, especially in dust-free or passive galaxies where the contributions of old SPs or biases from the lack of dust are significant. Similarly, the M⋆ calibration yields significantly better results for dusty and high-SFR galaxies where dust emission can otherwise bias the estimations.

A Versatile Automatic Weight Changer For Mass Comparators

This paper describes an automatic weight changer for changing weights on the pan of a mass comparator. The weight changer is easy to use, and is designed to be readily fitted to most common types of top-loading mass comparators and balances of maximum capacity 20 g to 200 g. The versatility of the weight changer is demonstrated by its use in improving the efficiency of routine mass calibration and by its use to compare weights in an evacuated chamber. In each instance the repeatability achieved is 20% or less of the resolution of the balance. The weight changer currently allows up to five weights (or groups of weights) to be automatically compared, but is easily modified to allow comparison of more weights.

A New Wide-field Infrared Survey Explorer Calibration of Stellar Mass

We derive new empirical scaling relations between Wide-field Infrared Survey Explorer (WISE) mid-IR (MIR) galaxy photometry and well-determined stellar masses from spectral energy distribution modeling of a suite of optical–infrared photometry provided by the Data Release 4 (DR4) Catalog of the GAMA-KiDS-VIKING survey of the southern G23 field. The MIR source extraction and characterization are drawn from the WISE Extended Source Catalogue and the archival ALLWISE catalog, combining both resolved and compact galaxies in the G23 sample to a redshift of 0.15. Three scaling relations are derived: W1 3.4 μm luminosity versus stellar mass, and WISE W1–W2, W1–W3 colors versus mass-to-light ratio (M/L, sensitive to a variety of galaxy types from passive to star-forming). For each galaxy in the sample, we then derive the combined stellar mass from these scaling relations, producing M ⋆ estimates with better than ∼25%–30% accuracy for galaxies with >109 M ⊙ and <40%–50% for lower-luminosity dwarf galaxies. We also provide simple prescriptions for rest-frame corrections and estimating stellar masses using only the W1 flux and the W1–W2 color, making stellar masses more accessible to users of the WISE data. Given a redshift or distance, these new scaling relations will enable stellar mass estimates for any galaxy in the sky detected by WISE with high fidelity across a range of M/L ratios.