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Application of portable near-infrared spectrometer to Heliotron J plasma diagnostics
摘要： A simple near-infrared (NIR) spectrometer with a wavelength range of 898–2130 nm has recently been applied to diagnose Heliotron J plasmas. It adopts a symmetrical crossed Czerny–Turner mount equipped with a thermoelectrically cooled 512 channel InGaAs linear sensor. Reciprocal linear dispersion was deduced to 96.37 nm/mm at the center of the detector. External ?lters can be inserted into the path of the collection optics to reject second-order spectra, as needed. Absolute intensity calibration was performed together with a visible spectrometer using a tungsten halogen lamp, and the effect of the transmittance fringe in the visible region of the applied long-pass ?lter on the NIR calibration was investigated. The intended application of the NIR spectrometer includes extending the wavelength region of a spectral monitor to less contaminated regions for Heliotron J plasma studies. In preliminary measurements, we observed the Paschen series for the hydrogen pellet injection plasma and two atomic helium lines, i.e., 2S-2P singlet and triplet lines, in helium gas puf?ng experiments. A continuum spectrum in this regime that is attributable to black-body radiation from hot spots on the plasma-facing components was identi?ed. In addition, this may also be used to monitor background radiation in the YAG-Thomson scattering signals near 1064 nm.
关键词： near-infrared spectrometer,YAG-Thomson scattering,plasma diagnostics,helium lines,black-body radiation,Paschen series,Heliotron J
更新于2025-09-10 09:29:36
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The mechanical and thermal setup of the GLORIA spectrometer
摘要： The novel airborne Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) measures infrared emission of atmospheric trace constituents. GLORIA comprises a cooled imaging Fourier transform spectrometer, which is operated in unpressurized aircraft compartments at ambient temperature. The whole spectrometer is pointed by the gimbal towards the atmospheric target. In order to reach the required sensitivity for atmospheric emission measurements, the spectrometer optics needs to operate at a temperature below 220 K. A lightweight and compact design is mandatory due to limited space and high agility requirements. The cooled optical system needs to withstand high pressure and temperature gradients, humidity, and vibrations. A new cooling system based on carbon dioxide and liquid nitrogen combined with high-performance insulation has been developed to meet the mechanical, thermal, and logistical demands. The challenging mechanical and spatial requirements lead to the development of a novel rigid linear slide design in order to achieve the large optical path difference for high spectral resolution. This paper describes the mechanical and thermal setup of GLORIA and presents the performance results on two different research aircrafts.
关键词： cooling system,atmospheric trace constituents,Fourier transform spectrometer,thermal design,mechanical design,GLORIA,infrared emission,airborne
更新于2025-09-10 09:29:36
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Design of a nonlinearity-corrected spectrometer based on curved prism
摘要： As a special type of dispersion element, a curved prism features high efficiency and no overlapping spectra, but suffers from nonlinear dispersion caused by the characteristics of the material. This paper proposes a design method for a nonlinearity-corrected spectrometer combining glass and optical plastic. We theoretically analyze the dispersion characteristics of the curved prism by using the method of equivalent triangular prism based on the theory of vector solving. This analysis is used to calculate the initial parameters for pairs of prisms. The method features simplified calculation, and the design achieves the benefits of compactness and light weight. The simulation results show that the spectral resolution varies from 4.9 to 7.1 nm in a wide spectrum (400–1000 nm); the nonlinearity ratio is nearly 1:2, making the dispersion across the wide spectrum nearly homogenized; and the spectral keystones and smiles of the system are less than 0.15 pixels. Under the same specifications, the weight of a combination of glass and optical plastic apparently decreases compared to that of the design with glass alone. The results demonstrate that the nonlinearity of the prism spectrometer is corrected to a large extent and merits such as light weight, compactness, and high throughout are achieved. This method can be applied to the field of biological detection, such as in a microscopic spectrometer.
关键词： Optical design,Spectrometer,Curved prism,Nonlinearity correction
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Drone Measurements of Solar-Induced Chlorophyll Fluorescence Acquired with a Low-Weight DFOV Spectrometer System
摘要： Solar induced chlorophyll fluorescence (SIF) emitted from plant canopies is now retrievable from space. In addition, SIF is now also routinely measured from fixed tower platforms. However there is a scale gap between temporally continuous tower measurements and spatially coarse satellite retrievals that is now being bridged by drone technology. Drone retrievals of SIF can be used to help unravel the structural and species component dependencies that occur across space on the scale of meters in heterogeneous vegetation types. Also when flown at sufficient altitude, drones can be used to simulate, and potentially validate satellite retrievals of SIF. We flew a dual field of view spectrometer system, the Piccolo doppio, above a boreal forest with the aim of retrieving SIF. Our flights were designed to assess both spatial heterogeneity of SIF driven by changes in vegetation cover type and to simulate satellite pixels by flying at a relatively high altitude.
关键词： Solar induced fluorescence,drone,Piccolo doppio spectrometer
更新于2025-09-10 09:29:36
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Quantification of gemcitabine intravenous drugs by direct measurement in chemotherapy plastic bags using a handheld Raman spectrometer
摘要： This aim of this study was to assess the ability of Raman spectroscopy to quantify antineoplastic drugs directly in the finished product in plastic bags using a handled Raman spectrometer. Gemcitabine diluted in 0.9% sodium chloride was analyzed at various concentrations ranging from 1 to 20 mg/mL directly through plastic bags using a handled 785 nm Raman spectrometer. In accordance with EMA guidelines, quantitative models were developed to predict gemcitabine concentration in bag using partial least squares (PLS) regression. In order to evaluate the transposability of the developed Raman method and the routine method (flow injection analysis with UV detection), independent samples were analyzed using both techniques. The impact of the plastic bag was also evaluated by analysis samples through two different bags. The best model was obtained after standard normal variates preprocessing (SNV) for 15 latent variables. This model presented an excellent correlation between predicted and theoretical concentration values (R2 of 0.9938 from the calibration set), a low limit of quantification (LLOQ) of 3.68 mg/mL and acceptable repeatability and intermediate precision lower than the expected acceptance limit of 5% over the entire concentration range tested (except for the average concentration of 5.73 mg/mL). For the 48 preparations higher than the LLOQ, the Bland-Altman approach showed the interchangeability of the wo methods with a difference bias of 2%. Moreover, no significant difference of predicted concentrations between the two containers tested (p = 0.189) was observed. Despite some limitations for low concentrations, this study clearly shows promising results for real-time monitoring of gemcitabine infusion preparations without removing samples. The non-invasive nature of this method should ensure the correct dose before administration to patients and with heightened safety for operators.
关键词： cytotoxic drug,handheld spectrometer,Raman spectroscopy,quantitative analysis,quality control
更新于2025-09-10 09:29:36
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A 400-GHz Wideband High-Gain Quartz-Based Single-Layered Folded Reflectarray Antenna for Terahertz Applications
摘要： Compact high-gain antennas are highly desired in the high speed terahertz (THz) wireless system, especially for the space limited application such as the high speed inter-link inside the high density wireless communication base station. To this end, a 400-GHz folded reflectarray (FRA) antenna with high gain, high aperture efficiency and compact profile is proposed in this paper. It is composed of a feed source, a single-layered reflectarray using a lithography process on quartz, and a wire-grid polarizer implemented by the printed-circuit-board (PCB) technology. A 3-D printed fixture is used to assemble all parts together. In order to design accurately the THz electromagnetic properties of the supporting dielectric materials are extracted by using a THz time-domain spectrometer system. Then, a single-layered phasing element, made up of a pair of orthogonally I-shaped structures with an open square ring, is proposed and designed based on the extracted material characteristics. Both phase compensation and polarization conversion can be realized by the proposed unit cell. A reflectarray is designed by using the proposed phasing element with the conventional array synthesizing theory, and a THz grid polarizer is designed with strips on a 0.127 mm Taconic TLY-5 substrate. The THz grid is placed in front of the THz feed and the reflectarray, which is fully reflective to the feed and transparent to the reflectarray. All components of the FRA antenna have been fabricated and assembled. Experiments show that the FRA prototype has a peak gain of 33.66 dBi at 400 GHz with an aperture efficiency of 33.65%, and a 3-dB gain bandwidth of 16% (357-421 GHz).
关键词： terahertz,3-D printing,high-gain,material characteristics,quartz substrate,single-layer,Folded reflectarray antenna,THz time-domain spectrometer
更新于2025-09-10 09:29:36
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A spectrometer for ultrashort gamma-ray pulses with photon energies greater than 10 MeV
摘要： We present a design for a pixelated scintillator based gamma-ray spectrometer for non-linear inverse Compton scattering experiments. By colliding a laser wakefield accelerated electron beam with a tightly focused, intense laser pulse, gamma-ray photons up to 100 MeV energies and with few femtosecond duration may be produced. To measure the energy spectrum and angular distribution, a 33 × 47 array of cesium-iodide crystals was oriented such that the 47 crystal length axis was parallel to the gamma-ray beam and the 33 crystal length axis was oriented in the vertical direction. Using an iterative deconvolution method similar to the YOGI code, modeling of the scintillator response using GEANT4 and fitting to a quantum Monte Carlo calculated photon spectrum, we are able to extract the gamma ray spectra generated by the inverse Compton interaction.
关键词： CsI scintillator,inverse Compton scattering,laser wakefield acceleration,gamma-ray spectrometer,GEANT4 simulations
更新于2025-09-09 09:28:46
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Toward Point-of-Care Drug Quality Assurance in Developing Countries: Comparison of Liquid Chromatography and Infrared Spectroscopy Quantitation of a Small-Scale Random Sample of Amoxicillin
摘要： Substandard antibiotics are thought to be a major threat to public health in developing countries and a cause of antimicrobial resistance. However, assessing quality outside of a laboratory setting, using simple equipment, is challenging. The aim of this study was to validate the use of a portable Fourier transform infrared (FT-IR) spectrometer for the identification of substandard antibiotics. Results are presented for amoxicillin packages from Haiti, Ghana, Sierra Leone, Democratic Republic of Congo, India, Papua New Guinea, and Ethiopia collected over the course of 6 months in 2017, including two field trips with the FT-IR to Ghana and Sierra Leone. Canadian samples were used as a control. Regarding drug quality, of 290 individual capsules of amoxicillin analyzed, 13 were found to be substandard with total active pharmaceutical ingredients (API) lying outside the acceptable range of 90–110%. Of these 13, four were below 80% API. The FT-IR reliably identified these outliers and was found to yield results in good agreement with the established pharmacopeia liquid chromatography protocol. We conclude that the portable FT-IR may be suitable to intercept substandard antibiotics in developing countries where more sophisticated techniques are not readily available.
关键词： developing countries,amoxicillin,portable FT-IR spectrometer,antimicrobial resistance,substandard antibiotics
更新于2025-09-09 09:28:46
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Optical Characterization of the SPT-3G Camera
摘要： The third-generation South Pole Telescope camera is designed to measure the cosmic microwave background across three frequency bands (centered at 95, 150 and 220 GHz) with ～ 16,000 transition-edge sensor (TES) bolometers. Each multi-chroic array element on a detector wafer has a broadband sinuous antenna that couples power to six TESs, one for each of the three observing bands and both polarizations, via lumped element ?lters. Ten detector wafers populate the detector array, which is coupled to the sky via a large-aperture optical system. Here we present the frequency band characterization with Fourier transform spectroscopy, measurements of optical time constants, beam properties, and optical and polarization ef?ciencies of the detec- tor array. The detectors have frequency bands consistent with our simulations and have high average optical ef?ciency which is 86, 77 and 66% for the 95, 150 and 220 GHz detectors. The time constants of the detectors are mostly between 0.5 and 5 ms. The beam is round with the correct size, and the polarization ef?ciency is more than 90% for most of the bolometers.
关键词： Frequency bands,Beam,Fourier transform spectrometer,Cosmic microwave background,Transition-edge sensor,Polarization,Optical ef?ciency,Time constant
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE 17th International Conference on Communication Technology (ICCT) - Chengdu (2017.10.27-2017.10.30)] 2017 IEEE 17th International Conference on Communication Technology (ICCT) - Research on spectral reconstruction technology based on fourier transform
摘要： This paper introduces the working principle and characteristics imaging spectrometer, and analyzes the acquisition methods, the advantages and disadvantages of several commonly used imaging spectrometers. Secondly, interference data acquisition method, interference image data recombination, interference image data preprocessing, spectral reconstruction and the specific processes of spectral calibration are analyzed and discussed. Finally, the experimental platform is built to test the influence of different focal length of lens on the interference image, and the concrete implementation of the background matlab code.
关键词： spectral reconstruction,interference,polarization,transform,imaging spectrometer
更新于2025-09-09 09:28:46