arXiv subjects

Iskander Gazizov

Publications and source records attributed to Iskander Gazizov.

4 recordsLinked to original sources

arXiv2025

An Open-Path Eddy-Covariance Laser Spectrometer for Simultaneous Monitoring of CO$_2$, CH$_4$, and H$_2$O

We present E-CAHORS $-$ a compact mid-infrared open-path diode-laser spectrometer designed for the simultaneous measurement of carbon dioxide, methane, and water vapor concentrations in the near-surface atmospheric layer. These measurements, combined with simultaneous data from a three-dimensional anemometer, can be used to determine fluxes using the eddy-covariance method. The instrument utilizes two interband cascade lasers operating at 2.78 $μ$m and 3.24 $μ$m within a novel four-pass M-shaped optical cell, which provides high signal power and long-term field operation without requiring active air sampling. Two detection techniques $-$ tunable diode laser absorption spectroscopy (TDLAS) and a simplified wavelength modulation spectroscopy (sWMS) $-$ were implemented and evaluated. Laboratory calibration demonstrated linear responses for all gases (R$^2$ $\approx$ 0.999) and detection precisions at 10 Hz of 311 ppb for CO$_2$, 8.87 ppb for CH$_4$, and 788 ppb for H$_2$O. Field tests conducted at a grassland site near Moscow showed strong correlations (R = 0.91 for CO$_2$ and H$_2$O, R = 0.67 for CH$_4$) with commercial LI-COR LI-7200 and LI-7700 analyzers. The TDLAS mode demonstrated lower noise and greater stability under outdoor conditions, while sWMS provided baseline-free spectra but was more sensitive to power fluctuations. E-CAHORS combines high precision, multi-species sensing capability with low power consumption (10 W) and a compact design (4.2 kg).

physics.ins-det↗

arXiv2024

Absorption and Dispersion: In Search of a Versatile Spectroscopic Technique

This paper investigates three spectroscopic techniques - Tunable Diode Laser Absorption Spectroscopy (TDLAS), Wavelength Modulation Spectroscopy (WMS), and Heterodyne Phase Sensitive Dispersion Spectroscopy (HPSDS) - to evaluate their performance in detecting carbon monoxide (CO) in nitrogen in a 31 m Herriot cell using an Interband Cascade Laser (ICL) emitting at 4559 nm. With the developed spectrometer, we can switch between the techniques with minimal hardware modifications. Calibration curves were established using simple peak-to-peak values from the recorded TDLAS, WMS, and HSPDS spectra, as well as after applying respective spectral models of the sensor responses followed by a least-squares fitting approach. We compare the results when using the different techniques with respect to obtained linearity, minimum detectable value (MDV), standard deviation of the method (sx0), coefficient of variation of the method (Vx0), limit of detection (LOD), and Allan-Werle deviation analysis. The results show significant differences in the performance of the three techniques when establishing calibration curves based on peak-to-peak evaluation of the recorded spectra. However, when establishing model-based calibration curves, a more uniform performance of the investigated techniques was found. The results demonstrate that TDLAS is a straightforward and robust technique but has a limited measurement range of up to 65 ppm. WMS offers a linear range of up to 100 ppm if an appropriate spectral model is applied and a baseline-free operation but requires careful calibration. HPSDS stands out for its wide linear range of up to 100 ppm and immunity to power fluctuations. However, its operation requires a complex mathematical model and radio frequency (RF) components.

physics.ins-det↗

arXiv2023

Spectrometer to Explore Isotopologues of Lunar Volatiles on Luna-27 Lander

The study of volatiles and the search for water are the primary objectives of the Luna-27 mission, which is planned to land on the south pole of the Moon in 2028. Here we present the tunable Diode Laser Spectrometer (DLS-L) that will be onboard the lander. The DLS-L will perform isotopic analysis of volatiles that are pyrolytically evolved from regolith. This article dives into the design of the spectrometer and the characterisation of isotopic signature retrieval. We look forward to expanding our knowledge of Lunar geochemistry by measuring D/H, 18O/17O/16O, 13C/12C ratios in situ, which could be the one-of-a-kind direct study of the lunar soil isotopy without sample contamination.

physics.ins-det↗

arXiv2022

Low-Resolution Imaging FMCW Lidar

We demonstrate the imaging capability of a frequency modulated continuous wave lidar based on a fiber bundle. The lidar constructs velocity and range images for hard targets at a rate of 60 Hz. The sensing range is up to 30 m with 20 mW of output power. The instrument employs custom electronics with seven parallel heterodyne receivers. An example of image recovery is presented on 6-pixel "pictures" of a spinning disk and a drone hovering in the air. In experiments, we also tested the laser tuning linearity correction with a phase-locked loop. We see the practicality of such a low-resolution system as a boost in scanning rate of conventional lidars or for direct target imaging with a further upgrade of pixel count.

physics.ins-det↗