Performance Of Spectrometer Research Articles

Remediation of Contaminated Soil by Polycyclic Aromatic Hydrocarbons Using Composting

Polycyclic aromatic hydrocarbons (PAHs) were one of the most concerning organic and toxic pollutants in the world. Since the 20th century, there had been no improvement in resolving or reducing the discharged or released amount of PAHs into the soil or environment. Detecting PAHs (PAHs) involved collecting environmental or biological samples, extracting PAHs using specialized techniques, and analyzing them with advanced methods like gas chromatography-mass spectrometer (GC-MS) or high performance liquid chromatography (HPLC). This process was crucial for assessing contamination levels, understanding health risks, and guiding environmental safety measures. There was no full replacement with existing technology and materials that would not release the PAHs. Now, the PAHs pollutant has caused many cases related to the impact of PAHs on the environment and human health, prompting immediate action for resolution. The remediation to remove the PAHs from the contaminated soil was conducted using the composting method. The few kinds of composting methods were vermicomposting, which used earthworms to decompose PAHs in the contaminated soil, in-vessel composting that ran the aerobic process under a close air space tank, and aerated pile that implemented the aerobic process in an open air space. The bulking agent of in-vessel composting and aerated composting was the same. Actually, these three composting methods were under bioremediation to remove PAHs from contaminated soil. There were a few challenges that would be faced by the government, the people, and the research in the future. Some recommendations have been provided to face these future challenges.

In situ rapid evaluation method of quality of peach kernels based on near infrared spectroscopy

This study aimed to perform a rapid in situ assessment of the quality of peach kernels using near infrared (NIR) spectroscopy, which included identifications of authenticity, species, and origins, and amygdalin quantitation. The in situ samples without any pretreatment were scanned by a portable MicroNIR spectrometer, while their powder samples were scanned by a benchtop Fourier transform NIR (FT-NIR) spectrometer. To improve the performance of the in situ determination model of the portable NIR spectrometer, the two spectrometers were first compared in identification and content models of peach kernels for both in situ and powder samples. Then, the in situ sample spectra were transferred by using the improved principal component analysis (IPCA) method to enhance the performance of the in situ model. After model transfer, the prediction performance of the in situ sample model was significantly improved, as shown by the correlation coefficient in the prediction set (Rp), root means square error of prediction (RMSEP), and residual prediction deviation (RPD) of the in situ model reached 0.9533, 0.0911, and 3.23, respectively, and correlation coefficient in the test set (Rt) and root means square error of test (RMSET) reached 0.9701 and 0.1619, respectively, suggesting that model transfer could be a viable solution to improve the model performance of portable spectrometers.

Imaging and spectrometric performance of SiC Timepix3 radiation camera

A Schottky barrier radiation detector and pixel imaging sensor fabricated from epitaxially grown SiC semiconductor were analyzed. The detector was based on an 80 μm thick epitaxial SiC layer. Capacitance-voltage measurement was performed to study the thickness of the space charge region of the detector as a function of applied bias. The results showed that the detector was completely depleted at a reverse bias higher than 300 V. The impurity concentration profile was also calculated, which indicated a net impurity concentration below 1.5×1014 cm-3. A prototype of a SiC Timpix3 radiation camera was fabricated, and its energy resolution was investigated using the 241Am radioisotope. The camera exhibited an energy resolution of 4.5 keV for 60 keV gamma photons. X-ray fluorescence photons (from 14 keV to 22 keV) were detected with a resolution below 2.0 keV. The imaging quality of the camera was investigated using a test object. The prototype showed a high-quality image performance with a stable count rate, which was determined from uniform intensity profiles extracted from parts of the test object image. A disadvantage of this prototype is that the radiation hits the detector from the side of the substrate and only then it reaches its active SiC epitaxial layer. This represents a dead layer that reduced the detection efficiency of X-rays below 10 keV.

Asymmetric Rowland circle geometries for spherically bent crystal analyzers in laboratory and synchrotron applications

We show that asymmetric operation of spherically bent crystal analyzers is an underutilized opportunity that can improve x-ray spectrometer performance and user operations in both the laboratory and synchrotron environments.

Comparison of microbial diversity and metabolites on household and commercial doenjang

In this study, the microbial diversity, free amino acid (FAA), and biological activities of household doenjang (HDJ) from four different regions and commercial doenjang (CDJ) four manufacturers were analyzed. And volatile flavor compound (VFC) and isoflavone profiles were analyzed using gas chromatograph-mass spectrometer (GC-MS) and high performance liquid chromatography (HPLC), respectively. The major bacterial genus in 1HDJ and 2HDJ was Bacillus (97.5%), while in 3HDJ and 4HDJ, it was Enterobacter (47.5%) and Pseudomonas (80%), respectively. Tetragenococcus was the main bacterial genus of CDJ. The Zygosaccharomyces genus among yeast was comparatively high in all samples. In all samples, glutamic acid predominated among the FAAs, and the 3-methyl butanal, benzeneacetaldehyde, and diallyl disulphide were major VFCs. CDJ contained higher levels of isoflavone-glycoside and total phenolics. Except for 3HDJ and 4CDJ, the isoflavone-aglycone and total flavonoid contents were higher in HDJ. The correlation between bacterial genus and metabolited of doenjang showed that Tetragenococcus was closely related to glutamic acid, Bacillus was related to aglycones and ammonia, and Pseudomonas was highly related to isovaleric acid. While, correlation between yeast genus and metabolited of doenjang confirmed that Candida, Hanseniaspora, and Saccharomyces were related with furfural, benzeneacetaldehyde, and 3-methyl butanal, respectively. The results of this study can be utilized as basic data for the industrialization and development of doenjang.

Enhancement of the signal-to-noise ratio by compressing the illumination of a spatial heterodyne Raman spectrometer

Improving the spectral signal-to-noise ratio is crucial for obtaining high-quality Raman spectra of target substances. To achieve a higher instrument signal-to-noise ratio in the development of spatial heterodyne Raman spectrometer, the effect of spatially compressed illumination on the spectral signal-to-noise ratio was theoretically analyzed. A spatial heterodyne Raman spectroscopic experimental setup with compressed illumination was constructed. The experimental results with ethanol validate the significant enhancement of the signal-to-noise ratio achieved through compressed illumination. The ethanol spectra exhibited signal-to-noise ratio enhancements ranging from 1.38 to 7.98 times under various excitation powers and integration times. These findings provide valuable guidance for further improving the performance of spatial heterodyne Raman spectrometers.

Direct design method for holographic grating imaging spectrometer and corresponding recording system

The combination of holographic gratings with freeform surface technology has led to a significant breakthrough in terms of the performance of imaging spectrometers. In this paper, a general direct design method that is capable of designing imaging spectrometers that include holographic gratings based on a complex-shaped surface substrate and their corresponding recording systems is proposed. The most important feature of this method is that the recording and imaging systems are designed within one optical system model, thus allowing for an optimal balance to be achieved between the aberration correction capability and the manufacturability of the holographic grating. To illustrate the effectiveness of the proposed method, three imaging spectrometers were designed that used holographic gratings manufactured by a recording system without auxiliary mirrors, a system with a spherical auxiliary mirror, and a system with a freeform auxiliary mirror. Ultimately, these three systems all achieved diffraction-limited imaging quality with minimal distortion.

Continuous wave cavity ringdown spectroscopy incorporating with an off-axis arrangement, white noise perturbation, and optical re-injection

We present an ultra-sensitive continuous wave cavity ringdown spectroscopy (cw-CRDS) spectrometer to record high resolution spectra of reactive radicals and ions in a pulsed supersonic plasma. The spectrometer employs a home-made external cavity diode laser as the tunable light source, with its wavelength modulated by radio-frequency white noise. The ringdown cavity with a finesse of ∼105 is arranged with an off-axis alignment. The combination of the off-axis cavity and the white-noise perturbed laser yields quasi-continuum laser-cavity coupling without the need of mode matching. The cavity is further incorporated with an extra multi-pass cavity for optical re-injection of light reflected off the master cavity, which significantly increases the throughput power of the high-finesse cavity. A fast switchable semiconductor optical amplifier is used to modulate the cw laser beam to square wave pulses and to initialize timing controlled ringdown events, which are synchronized to the plasma pulses with an accuracy of ∼3 µs. The performance and potential of the cw-CRDS spectrometer are illustrated and discussed, based on the high resolution near-infrared spectroscopic detection of trace 13C13C radicals generated in a pulsed supersonic C2H2/Ar plasma with a pulse duration of ∼50 µs.

Design and simulated performance of a high-resolution magnetic proton recoil spectrometer for deuterium–tritium neutrons

Neutron emission energy and time spectra of deuterium–tritium plasma contain abundant information about the fusion yield, ion temperature, and nuclear burn history. Magnetic recoil spectrometers have been employed in measuring time-integrated energy spectra in inertial confinement fusion (ICF) experiments. As the fusion yield increases, time-resolved neutron diagnostics is urgently desired for understanding complex fusion physics. Herein, we design a compact magnetic proton recoil (MPR) spectrometer based on a 90 degree permanent magnet. The entrance and exit of the magnet are second-order shapes to eliminate two major second-order aberrations. The energy resolution and time resolution for 14MeV neutrons achieve 97keV and 1.6ns, respectively, under the detection efficiency of 7.4×10−8cm2. A quadratic relation is found between detection efficiency and energy resolution when configurations are optimal. Monte Carlo simulations are accomplished to study the performance in measuring time-integrated energy spectra, emission time spectra, and time-resolved energy spectra, demonstrating the potential of high-resolution MPR spectrometers in future high-yield ICF experiments.

Spectrometric performance of SiC radiation detectors at high temperature

In this work, we have investigated the performance of a 4H–SiC radiation sensor in the temperature range from 25 °C to 450 °C to explore its compatibility as detector of fast ion losses in plasma diagnostic of future nuclear fusion reactors. To simulate the escape of fusion-born alpha particles in D-T (deuterium-tritium) fusion plasmas, spectroscopic measurements were carried out in a vacuum chamber by irradiating the detector with a 3.5 MeV alpha beam from a Tandem accelerator. The detector was found to have an energy resolution ≤2% over the entire temperature range analyzed. Relevantly, the excellent spectrometric capabilities of the device have allowed us to calculate from experimental data, with unprecedented accuracy, the average energy required to create a single electron-hole pair in 4H–SiC as a function of temperature.

Effect of detector crystal size on Compton suppression factors

The geometrical parameters which affect the suppression factor for an HPGe (High Purity Germanium)-NaI Compton suppression spectrometer were studied by a Monte Carlo simulation with the EGS4 system. The spectrums were crated for 5 energy values ranging from 200 keV to 2 MeV. Compton suppression factors (CSFs), the parameters characterizing the system performance, were calculated for different HPGe crystal parameters. It was observed that to obtain better Compton suppressed factors, a laboratory must choose as small HPGe crystal as possible for energy values up to 400 keV. However, for higher energies up to 2 MeV, larger HPGe crystals provide better Compton suppression systems. These findings suggest that the choice of HPGe crystal size can significantly impact the performance of a Compton suppression spectrometer and should be carefully considered in its design and optimization.

Automatic and Quantitative Measurement of Spectrometer Aberrations.

The performance of electron energy loss spectrometers can often be limited by their electron optical aberrations. Due to recent developments in high energy resolution and momentum-resolved electron energy loss spectroscopy (EELS), there is renewed interest in optimizing the performance of such spectrometers. For example, the "ω - q" mode of momentum-resolved EELS, which uses a small convergence angle and requires aligning diffraction spots with the slot aperture, presents a challenge in the realignments of the spectrometer required by the adjustment of the projection lenses. Automated and robust alignment can greatly benefit such a process. The first step toward this goal is automatic and quantitative measurement of spectrometer aberrations. We demonstrate the measurement of geometric aberrations and distortions in EELS within a monochromated scanning transmission electron microscope (STEM). To better understand the results, we present a wave mechanical simulation of the experiment. Using the measured aberration and distortion coefficients as inputs to the simulation, we find a good match between the simulation and experiment, verifying formulae used in the simulation. From verified simulations with known aberration coefficients, we can assess the accuracy of measurements. Understanding the errors and inaccuracies in the procedure can guide further progress in aberration measurement and correction for new spectrometer developments.

Design and performance of a dual stage asymmetric ion funnel interface

A dual-stage asymmetric ion funnel (DAIF) interface has been designed to remove the bottleneck in ion transmission from atmospheric ionization to the vacuum chamber. This leads to increased sensitivity and improved performance of the mass spectrometer. Both ion funnels are asymmetrically constructed, with a precisely calculated 7 mm radial offset in the ion path. This accelerates the separation of ions from the neutral stream, reduces contamination, and enhances the flow field and vacuum system. The performance of the DAIF interface was investigated through numerical simulations and experimental tests, utilizing the Hexin API-5000 TOFMS as our experimental platform. The results indicate that the asymmetric ion funnel has a powerful desolvation capability, achieving a high transmission efficiency of 87.9%. The novel DAIF interface enhances sensitivity by an order of magnitude. In addition, the robustness of the instrument can be improved by efficiently removing neutral molecules and contaminants from the DAIF. These features make DAIF suitable for various MS systems and ionizations.

High-resolution compact spectrometer based on periodic tapered coreless fiber.

This Letter proposes a method that balances miniaturization and high performance of fiber optic speckle spectrometers. The periodically tapered coreless fiber is used as the scattering element to excite more higher-order modes in the coreless fiber. As a result, a remarkable spectral resolution of 0.03 nm in the near-infrared spectrum can be achieved with a 5-cm-long fiber. Narrow linewidth and broadband spectra in the wavelength of 1540-1560 nm are reconstructed separately, demonstrating the excellent performance of the designed all-fiber spectrometer. The spectral resolution of our proposed spectrometer is comparable to that of a 2-m multimode fiber spectrometer and has a significant improvement in miniaturization.

A Tabletop X-Ray Tomography Instrument for Nanometer-Scale Imaging: Demonstration of the 1,000-Element Transition-Edge Sensor Subarray

We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines a high spatial resolution scanning electron microscope (SEM) with a highly efficient and pixelated TES spectrometer to reconstruct three-dimensional maps of nanoscale integrated circuits (ICs). A 240-pixel prototype spectrometer was recently used to reconstruct ICs at the 130 nm technology node, but to increase imaging speed to more practical levels, the detector efficiency needs to be improved. For this reason, we are building a spectrometer that will eventually contain 3,000 TES microcalorimeters read out with microwave superconducting quantum interference device (SQUID) multiplexing, and we currently have commissioned a 1,000 TES subarray. This still represents a significant improvement from the 240-pixel system and allows us to begin characterizing the full spectrometer performance. Of the 992 maximimum available readout channels, we have yielded 818 devices, representing the largest number of TES x-ray microcalorimeters simultaneously read out to date. These microcalorimeters have been optimized for pulse speed rather than purely energy resolution, and we measure a FWHM energy resolution of 14 eV at the 8.0 keV Cu K$\alpha$ line.

Metals quantification in e-cigarettes liquids by Total Reflection X-ray Spectrometry

Electronic cigarettes (e-cig) have gained popularity around the world and its health risks demands more research. This study aims at characterizing e-cig liquids (e-liquids) and its constituents by Total Reflection X-ray Spectrometry (TXRF). The internal standard method was the quantification procedure employed. The spectrometer's performance was evaluated with one certified reference material and spiked samples. It was possible to quantify K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Br, and Pb in the e-liquids. Concentrations above the limit for potable water were found in 10 out of 38 samples. Principal component analysis was useful for identifying toxic samples. TXRF is a promising technique for e-liquids evaluation due to its simplicity and performance.

Eupatorium adenophorum Spreng leaves extract/potassium iodide as a highly sustainable inhibitor for the corrosion protection of steel in citric acid solution

Plants extract inhibitor has the standout merits of low-cost, eco-friendly and rich natural raw resources. The synergism between Eupatorium adenophorum Spreng leaves extract (EASLE) and KI for the corrosion of cold rolled steel (CRS) in citric acid (H3C6H5O7) solution was tested in detail by weight loss and electrochemical techniques. The micro-morphology of CRS surface was fully characterized by both scanning electron microscope (SEM) and atomic force microscope (AFM). Fourier transform infrared spectrometer (FTIR) and high performance liquid chromatography (HPLC) were employed to deeply analyze the main bio-active components in EASLE. The results show that either EASLE or KI can moderately inhibits the corrosion of CRS, and their maximum inhibition efficiency values are below 75%. As EASLE is combined with KI, their mixture has a better inhibition of over 90%. There is a synergism between EASLE and KI, and the corresponding synergism parameters are all higher than unity with a highest value of 3.5 for 400 mg L-1 EASLE/ 100 mg L-1 KI at 60 °C. The adsorption of EASLE, KI or EASLE/KI mixture follows Langmuir isotherm, and the adsorption is strengthened for the synergistic mixture. EASLE mainly retards the anodic reaction, while EASLE/KI mixture drastically inhibits both cathodic and anodic reactions simultaneously with a low corrosion current densities of 17.8 µA cm−2. Nyquist graph appears a depressed capacitive loop at high frequencies followed by an inductive loop at low frequencies. EASLE/KI mixture has larger charge transfer resistance (Rt) comparing with either EASLE or KI. Rt values for 500 mg L-1 EASLE, 100 mg L-1 KI and 500 mg L-1 EASLE/100 mg L-1 KI mixture are 464.9, 382.9 and 1068 Ω cm2, respectively. SEM and AFM micro-images clearly confirm that the corrosion extent as well as surface roughness of CRS surface were sharply dropped after adding EASLE/KI mixture. The main bio-active components in EASLE are phenylpropanoids like chlorogenic acid, caffeic acid and ferulic acid.

Direct performance comparison of antiresonant and Kagome hollow-core fibers in mid-IR wavelength modulation spectroscopy of ethane.

In this paper, we experimentally asses the performance of wavelength modulation spectroscopy-based spectrometers incorporating 1.3 m-long gas absorption cells formed by an antiresonant hollow core fiber (ARHCF) and a Kagome hollow core fiber. To evaluate the discrepancies with minimum methodology error, the sensor setup was designed to test both fibers simultaneously, providing comparable measurement conditions. Ethane (C2H6) with a transition located at 2996.88 cm-1 was chosen as the target gas. The experiments showed, that due to better light guidance properties, the ARHCF-based sensor reached a minimum detection limit of 4 ppbv for 85 s integration time, which is more than two times improvement in comparison to the result obtained with the Kagome fiber.

Diode laser absorption spectroscopy for real-time detection of breath oxygen

In this paper, a high-resolution laser absorption spectrometer is developed using a distributed feedback (DFB) diode laser in the spectral region near 760 nm, which is designed for the highly sensitive detection of oxygen (O2) in breathing gas. To investigate the spectrometer performance, O2 absorption line at 13146.580 cm−1 was selected, and detailed experiments on air-broadening coefficient, self-broadening coefficient and spectral line intensity were conducted. Compared to the corresponding data listed in the HITRAN2020 database, the results show that the errors for air-broadening coefficient, self-broadening coefficient and line intensity, were −6.832%, 4.082% and 4.667%, respectively. Finally, the developed laser absorption spectrometer was primarily evaluated for real-time analysis of O2 content in human breath analysis. The results indicate that the measured O2 concentrations in several volunteers range from 16% to 16.5%, which is in agreement with the levels reported in the literature for healthy humans.

Li2100deplMoO4 Scintillating Bolometers for Rare-Event Search Experiments

We report on the development of scintillating bolometers based on lithium molybdate crystals that contain molybdenum that has depleted into the double-β active isotope 100Mo (Li2100deplMoO4). We used two Li2100deplMoO4 cubic samples, each of which consisted of 45-millimeter sides and had a mass of 0.28 kg; these samples were produced following the purification and crystallization protocols developed for double-β search experiments with 100Mo-enriched Li2MoO4 crystals. Bolometric Ge detectors were utilized to register the scintillation photons that were emitted by the Li2100deplMoO4 crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc Underground Laboratory (Spain). We observed that the Li2100deplMoO4 scintillating bolometers were characterized by an excellent spectrometric performance (∼3–6 keV of FWHM at 0.24–2.6 MeV γs), moderate scintillation signal (∼0.3–0.6 keV/MeV scintillation-to-heat energy ratio, depending on the light collection conditions), and high radiopurity (228Th and 226Ra activities are below a few µBq/kg), which is comparable with the best reported results of low-temperature detectors that are based on Li2MoO4 using natural or 100Mo-enriched molybdenum content. The prospects of Li2100deplMoO4 bolometers for use in rare-event search experiments are briefly discussed.