Review of Scientific Instruments最新文献

The visible and infrared Moon And Jupiter Imaging Spectrometer (MAJIS), aboard the JUpiter ICy Moons Explorer (JUICE) spacecraft, will characterize the composition of the surfaces and atmospheres of the Jupiter system. Prior to the launch, a campaign was carried out to obtain the measurements needed to calibrate the instrument. The aim was not only to produce data for the calculation of the radiometric, spectral, and spatial transfer functions but also to evaluate MAJIS performance, such as signal-to-noise ratio and amount of straylight, under near-flight conditions. Here, we first describe the setup implemented to obtain these measurements, based on five optical channels. We notably emphasize the concepts used to mitigate thermal infrared emissions generated at ambient temperatures, since the MAJIS spectral range extends up to 5.6 µm. Then, we characterize the performance of the setup by detailing the validation measurements obtained before the campaign. In particular, the radiometric, geometric, and spectral properties of the setup needed for the inversion of collected data and the calculation of the instrument's calibration functions are presented and discussed. Finally, we provide an overview of conducted measurements with MAJIS, and we discuss unforeseen events encountered during the on-ground calibration campaign.

One regime of experimental particle-laden flow study involves ejecta microjets-often defined as a stream of micrometer-scale particles generated through shock interaction with a non-uniform surface and generally travel above 1 km/s. In order to capture the change in characteristics as a function of propagation time, we apply a multi-frame x-ray radiography platform to observe and track the jet transport dynamics. A synchrotron x-ray source allows us to perform quantitative analyses and comparisons between the eight images captured by the imaging system. Observation of a single jet through time allows the use of a cross correlation algorithm to independently track various regions within the jet and quantify the jet expansion over time using normalized area and normalized areal density values. Through a comparison with the calculated values of ballistic transport, these findings show less expansion than expected for ballistically transporting particles. This work combines multi-frame synchrotron radiography with image tracking to establish a foundation for future studies on jet transport and particle interaction dynamics.

A new high energy proton radiography facility PRIOR-II (Proton Microscope for FAIR) has been designed, constructed, and successfully commissioned at the GSI Helmholtzzentrum für Schwerionenforschung (Darmstadt, Germany) pushing the technical boundaries of charged particle radiography with normal conducting magnets to the limits. The setup is foreseen to become a new and powerful user facility for carrying out fundamental science experiments in the fields of plasma and shock wave physics, material science, and medical physics. It will help address several unsolved scientific challenges, which require high-speed and precise non-invasive diagnostic methods capable of probing matter with up to 100 g/cm2 areal density. PRIOR-II is specifically designed to utilize the full timing capabilities of the SIS-18 synchrotron at GSI for ultra-fast dynamic experiments with up to 4 GeV protons and will also be fielded at the future FAIR facility, where higher proton energies and beam intensities will be available. This will enable experiment geometries with even higher areal densities, more flexible experiment timing, and further enhanced spatial resolution.

Understanding the confinement of fast ions is crucial for plasma heating and non-inductive current drive, i.e., for the operation of a fusion reactor. Interactions between fast ions and magnetohydrodynamic instabilities can reduce the performance of fusion reactions. Measuring the spatial shape and amplitude is crucial for constraining numerical modeling of the interaction between fast ions and these instabilities. Soft x rays can be used to study these magnetic instabilities. In particular, SXR tomography is used to reconstruct the two-dimensional profile of the SXR emissivity requiring only line integrated measurements, thus providing the spatial structure of the instabilities. This work presents SXR tomography reconstruction performed on synthetic SXR emissions from the Mega Ampere Spherical Tokamak Upgrade device. The synthetic SXR emissions are derived from time dependent tokamak transport data analysis code (TRANSP/NUBEAM) simulations. Different tomographic reconstruction models are compared, and the effect of two additional fans of intersecting lines of sight on the reconstructions' performances is investigated. The additional intersecting lines of sight greatly improve the accuracy of the reconstructions.

Micro-absorption spectroscopy is a useful tool for studying the biological characteristics of single cells. However, the weak spectral signal, due to low absorption caused by the tiny optical path length of the cell, makes the spectral data noisy and difficult to analyze. This paper describes a device for single-cell microspectroscopy measurement that integrates an optical fiber spectrometer and an image CCD within a microscopic system, allowing for the simultaneous acquisition of morphology information and the absorption spectrum of a single cell. The device utilizes an illumination source driven by modulated current sources instead of constant current sources and the corresponding spectral signal extraction method to reduce noise levels. It also features a transparent temperature-controlled sample chamber for regulating the sample's temperature, as the absorption of cells may change with temperature. Due to the unwanted baseline drift in the spectral signals, a method of analyzing the similarity degree between the measured spectrum and the standard spectrum is proposed to study the characteristic variation of cells. To verify the feasibility of this method, the device was used for the microscopic spectral measurement and analysis of single red blood cells. The results showed that the variation patterns of spectral parameters correspond to the cell's responses to changes in temperature and storage duration.

This paper reports a compact fiber optical electric field (E-field) sensor aiming for the precise detection of transient E-field distributions. Here, a reflective polarization-reciprocal optical path is proposed, which inherently mitigates the temperature-induced birefringence interference of the electro-optical crystal without the need for additional optical elements, thereby facilitating a reduced-size sensing probe. Furthermore, an adaptive particle swarm optimization (A-PSO) algorithm has been utilized for the first time to optimize the insulation structure of the optical E-field sensor, which significantly suppresses field distortion within the sensing region by 50%. This method addresses the technical gap in optical E-field sensor structure optimization, providing an effective means to improve its spatial resolution. The experimental results demonstrate that the proposed sensor exhibits a broad response frequency range from 50 Hz to 15 MHz, with a sensitivity of 0.675 V/kV cm-1. The proposed sensor successfully monitors the spatial distribution of electric fields in the lightning interception region of a lightning rod, thereby validating its effectiveness.

Patterned magnetic films have been applied widely in communication technology for meeting the development of miniaturization and high frequency. However, there has been some debate about the measuring of the anisotropy field, which is significant for deciding the electromagnetic performance. In the paper, we proposed the measurement of the anisotropy field using anisotropic ferromagnetic resonances in patterned permalloy magnetic films. The anisotropy in patterned permalloy with different magnetic stripe widths can be observed qualitatively by the hysteresis loop along in-plane x and y directions, which induces the anisotropic ferromagnetic resonant behaviors. The anisotropy field can be calculated quantificationally by fitting the Kittel equation when the single resonant peak appears under applied magnetic fields. The values of the anisotropy field obtained by anisotropic ferromagnetic resonances are on the lower side to compare with the ones obtained by the energy difference between easy anis and hard axis. Our results can provide an extra method for measuring the anisotropy field, which can be useful for designing electromagnetic devices and potential applications in next-generation wireless communication.

During the data collection of x-ray diffraction experiments with various detectors, background signals are often unavoidable along with the sample signal. Addressing the background during post-data analysis is not a straightforward task. In this work, we introduced an algorithm specifically designed to handle centrally symmetric two-dimensional x-ray diffraction data and processed the data using the Python programming language. The two-dimensional data are first transformed from Cartesian coordinates to polar coordinates. Second, utilizing existing background processing algorithms, one-dimensional background curves are identified for each azimuth angle. These background data are then merged to generate two-dimensional background data. Finally, by subtracting the background from the original data, we obtain the clear diffraction signal. The algorithm can effectively remove the background from x-ray diffraction data and exhibits the ability to handle backgrounds with high intensity and irregular shapes, and the discernibility of the weak signal is significantly enhanced. Moreover, researchers have the flexibility to choose whether to preserve or eliminate the signals from additional amorphous components based on their needs. This algorithm will provide researchers with the possibility for further data analysis.

We have developed a built-in gasket for the Bridgman-type opposed-anvil high-pressure cell, featuring a PTFE (Teflon) capsule of ϕ 2.0 (1.5) × 2.5 mm3, filled with a liquid pressure-transmitting medium. This gasket, comprising a stainless-steel plane disk, a stainless-steel support ring, and pyrophyllite support gaskets, has enhanced the sample space height, allowed for precise adjustment of the anvil top area, and facilitated easy electrical insulation of lead wires. We calibrated the pressure by detecting phase transitions in Bi and Sn through resistivity measurements, achieving nearly hydrostatic pressure up to 9.4 GPa with this cell. Our analysis of the deformation of the gasket components under force has provided guidelines for effective pressurization.

Well-constructed instruments may continue to perform beyond their manufacturer-supported service lifetime, which is typically limited by computer operating system compatibility or the availability of spare parts. Often, such equipment is condemned to surplus and destroyed. End-of-life plans that retain some of the material and energy used to create scientific instruments are of interest, just as in other manufacturing sectors. This is especially true when an instrument can be given new capabilities beyond those for which it was originally designed, maybe even surpassing newly built models. We report the "upcycling" of a Wyatt multiangle, multidetector instrument designed for static light scattering (SLS). The instrument retains SLS capability but was extended to multiangle, multidetector, multicorrelator dynamic light scattering operation by adding readily available fiber optics, detectors, and a modern, multichannel autocorrelator. Because one of the main catalysts of obsolescence is software compatibility, data processing was implemented with the stable Microsoft Excel platform, including a graphical user interface. Instrument performance is demonstrated with microemulsions, protein and polymer solutions, suspensions of latex particles, and suspensions of cellulose nanocrystals.