scholarly journals Quartz-Enhanced Photoacoustic Detection of Ethane in the Near-IR Exploiting a Highly Performant Spectrophone

2020 ◽  
Vol 10 (7) ◽  
pp. 2447 ◽  
Author(s):  
Fabrizio Sgobba ◽  
Giansergio Menduni ◽  
Stefano Dello Russo ◽  
Angelo Sampaolo ◽  
Pietro Patimisco ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
Quartz Tuning Fork ◽  
Integration Time ◽  
Exciting Light ◽  
Acoustic Detection ◽  
Photoacoustic Detection ◽  
Near Ir ◽  
Lock In

In this paper the performances of two spectrophones for quartz-enhanced photoacoustic spectroscopy (QEPAS)-based ethane gas sensing were tested and compared. Each spectrophone contains a quartz tuning fork (QTF) acoustically coupled with a pair of micro-resonator tubes and having a fundamental mode resonance frequency of 32.7 kHz (standard QTF) and 12.4 kHz (custom QTF), respectively. The spectrophones were implemented into a QEPAS acoustic detection module (ADM) together with a preamplifier having a gain bandwidth optimized for the respective QTF resonance frequency. Each ADM was tested for ethane QEPAS sensing, employing a custom pigtailed laser diode emitting at ~1684 nm as the exciting light source. By flowing 1% ethane at atmospheric pressure, a signal-to-noise ratio of 453.2 was measured by implementing the 12.4 kHz QTF-based ADM, ~3.3 times greater than the value obtained using a standard QTF. The minimum ethane concentration detectable using a 100 ms lock-in integration time achieving the 12.4 kHz custom QTF was 22 ppm.

scholarly journals Fiber-Coupled Quartz-Enhanced Photoacoustic Spectroscopy System for Methane and Ethane Monitoring in the Near-Infrared Spectral Range

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5607
Author(s):  
Giansergio Menduni ◽  
Fabrizio Sgobba ◽  
Stefano Dello Russo ◽  
Ada Cristina Ranieri ◽  
Angelo Sampaolo ◽  
...  
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Near Infrared ◽  
Integration Time ◽  
Vapor Concentration ◽  
Acoustic Detection ◽  
Near Ir ◽  
Qepas Signal ◽  
Infrared Spectral ◽  
Lock In ◽  
Minimum Detection Limits

We report on a fiber-coupled, quartz-enhanced photoacoustic spectroscopy (QEPAS) near-IR sensor for sequential detection of methane (CH4 or C1) and ethane (C2H6 or C2) in air. With the aim of developing a lightweight, compact, low-power-consumption sensor suitable for unmanned aerial vehicles (UAVs)-empowered environmental monitoring, an all-fiber configuration was designed and realized. Two laser diodes emitting at 1653.7 nm and 1684 nm for CH4 and C2H6 detection, respectively, were fiber-combined and fiber-coupled to the collimator port of the acoustic detection module. No cross talk between methane and ethane QEPAS signal was observed, and the related peak signals were well resolved. The QEPAS sensor was calibrated using gas samples generated from certified concentrations of 1% CH4 in N2 and 1% C2H6 in N2. At a lock-in integration time of 100 ms, minimum detection limits of 0.76 ppm and 34 ppm for methane and ethane were achieved, respectively. The relaxation rate of CH4 in standard air has been investigated considering the effects of H2O, N2 and O2 molecules. No influence on the CH4 QEPAS signal is expected when the water vapor concentration level present in air varies in the range 0.6–3%.

scholarly journals Application of Micro Quartz Tuning Fork in Trace Gas Sensing by Use of Quartz-Enhanced Photoacoustic Spectroscopy

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5240 ◽  
Author(s):  
Haoyang Lin ◽  
Zhao Huang ◽  
Ruifeng Kan ◽  
Huadan Zheng ◽  
Yihua Liu ◽  
...  
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Tuning Fork ◽  
Gas Sensing ◽  
Modulation Depth ◽  
Quartz Tuning Fork ◽  
Acoustic Resonance ◽  
Photoacoustic Signal ◽  
Integration Time ◽  
Sampling Volume ◽  
Qepas Sensor

A novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor based on a micro quartz tuning fork (QTF) is reported. As a photoacoustic transducer, a novel micro QTF was 3.7 times smaller than the usually used standard QTF, resulting in a gas sampling volume of ~0.1 mm3. As a proof of concept, water vapor in the air was detected by using 1.39 μm distributed feedback (DFB) laser. A detailed analysis of the performance of a QEPAS sensor based on the micro QTF was performed by detecting atmosphere H2O. The laser focus position and the laser modulation depth were optimized to improve the QEPAS excitation efficiency. A pair of acoustic micro resonators (AmRs) was assembled with the micro QTF in an on-beam configuration to enhance the photoacoustic signal. The AmRs geometry was optimized to amplify the acoustic resonance. With a 1 s integration time, a normalized noise equivalent absorption coefficient (NNEA) of 1.97 × 10−8 W·cm−1·Hz−1/2 was achieved when detecting H2O at less than 1 atm.

scholarly journals Piezo-enhanced acoustic detection module for mid-infrared trace gas sensing using a grooved quartz tuning fork

2019 ◽  
Vol 27 (24) ◽  
pp. 35267 ◽  
Author(s):  
Shangzhi Li ◽  
Hongpeng Wu ◽  
Ruyue Cui ◽  
Angelo Sampaolo ◽  
Pietro Patimisco ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Gas Sensing ◽  
Quartz Tuning Fork ◽  
Trace Gas ◽  
Acoustic Detection ◽  
Mid Infrared ◽  
Trace Gas Sensing

scholarly journals A Novel Type Room Temperature Surface Photovoltage Gas Sensor Device 

2018 ◽  
Author(s):  
Monika Kwoka ◽  
Michal A. Borysiewicz ◽  
Pawel Tomkiewicz ◽  
Anna Piotrowska ◽  
Jacek Szuber
Keyword(s):  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Fast Response ◽  
Surface Photovoltage ◽  
Kelvin Probe ◽  
Sensor Device ◽  
Developed Surface

In this paper a novel type of a highly sensitive gas sensor device based on the surface photovoltage effect is described. The developed surface photovoltage gas sensor is based on a reverse Kelvin probe approach. As the active gas sensing electrode the porous ZnO nanostructured thin films are used deposited by the direct current (DC) reactive magnetron sputtering method exhibiting the nanocoral surface morphology combined with an evident surface nonstoichiometry related to the unintentional surface carbon and water vapor contaminations. Among others, the demonstrated SPV gas sensor device exhibits a high sensitivity of 1 ppm to NO2 with a signal to noise ratio of about 50 and a fast response time of several seconds under the room temperature conditions.

Two-component gas sensing with MIR dual comb spectroscopy

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Leonard Nitzsche ◽  
Jens Goldschmidt ◽  
Armin Lambrecht ◽  
Jürgen Wöllenstein
Keyword(s):  
Carbon Monoxide ◽  
Nitrous Oxide ◽  
Gas Sensing ◽  
Integration Time ◽  
Relative Precision ◽  
Acquisition Rate ◽  
Mid Infrared ◽  
Two Component ◽  
Absorption Features

Abstract A dual comb spectrometer is used as gas sensor for the parallel detection of nitrous oxide (N2O) and carbon monoxide (CO). These gases have overlapping absorption features in the mid-infrared (MIR) at a wavelength of 4.6 µm. With a spectra acquisition rate of 10 Hz, concentrations of 50 ppm N2O and 30 ppm CO are monitored with a relative precision of 6 × 10 − 3 6\times {10^{-3}} and 3 × 10 − 3 3\times {10^{-3}} respectively. The limit of detections are 91 ppb for N2O and 50 ppb for CO for an integration time of 25 s. The system exhibits a linear sensitivity from 2 ppm to 100 ppm with coefficients of determination of 0.99998 for N2O and 0.99996 for CO.

scholarly journals Acoustic Detection Module Design of a Quartz-Enhanced Photoacoustic Sensor

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1093 ◽  
Author(s):  
Tingting Wei ◽  
Hongpeng Wu ◽  
Lei Dong ◽  
Frank Tittel
Keyword(s):  
Near Infrared ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Acoustic Detection ◽  
Numerous Application ◽  
Mid Infrared ◽  
Module Design ◽  
Laser Sources ◽  
Infrared Laser Sources ◽  
Reliability And Robustness

This review aims to discuss the latest advancements of an acoustic detection module (ADM) based on quartz-enhanced photoacoustic spectroscopy (QEPAS). Starting from guidelines for the design of an ADM, the ADM design philosophy is described. This is followed by a review of the earliest standard quartz tuning fork (QTF)-based ADM for laboratory applications. Subsequently, the design of industrial fiber-coupled and free-space ADMs based on a standard QTF for near-infrared and mid-infrared laser sources respectively are described. Furthermore, an overview of the latest development of a QEPAS ADM employing a custom QTF is reported. Numerous application examples of four QEPAS ADMs are described in order to demonstrate their reliability and robustness.

Improved Semi-Bit Differential Acquisition Method for Navigation Bit Sign Transition and Code Doppler Compensation in Weak Signal Environment

2020 ◽  
Vol 73 (4) ◽  
pp. 892-911 ◽  
Author(s):  
M. Nezhadshahbodaghi ◽  
M. R. Mosavi ◽  
N. Rahemi
Keyword(s):  
Signal To Noise Ratio ◽  
Integration Time ◽  
Data Sets ◽  
Weak Signal ◽  
Differential Acquisition ◽  
Global Positioning ◽  
Signal Environment ◽  
Correlation Techniques ◽  
Transition Issues ◽  
Acquisition Method

The presence of code Doppler and navigation bit sign transitions means that the acquisition of global positioning system (GPS) signals is difficult in weak signal environments where the output signal-to-noise ratio (SNR) is significantly reduced. Post-correlation techniques are typically utilised to solve these problems. Despite the advantages of these techniques, the post-correlation techniques suffer from problems caused by the code Doppler and the navigation bit sign transitions. We present an improved semi-bit differential acquisition method which can improve the code Doppler and the bit sign transition issues in the post-correlation techniques. In order to overcome the phenomenon of navigation bit sign transitions, the proposed method utilises the properties of the navigation bit. Since each navigation bit takes as long as 20 ms, there would be 10 ms correlations duration integration time between the received signal and the local coarse/acquisition (C/A) code in which the navigation bit sign transitions will not occur. Consequently, this problem can be cancelled by performing 10 ms correlations in even and odd units separately. Compensation of the code Doppler is also accomplished by shifting the code phase of the correlation results. To validate the performance of our suggested method, simulations are performed based on three data sets. The results show that the quantity of required input SNR to detect at least four satellites in the proposed method is − 48·3 dB, compared with − 20 dB and − 9 dB, respectively, in traditional differential and non-coherent methods.

scholarly journals Dynamic Responses of Electrically Driven Quartz Tuning Fork and qPlus Sensor: A Comprehensive Electromechanical Model for Quartz Tuning Fork

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2686
Author(s):  
Manhee Lee ◽  
Bongsu Kim ◽  
Sangmin An ◽  
Wonho Jhe
Keyword(s):  
Resonance Frequency ◽  
Quality Factor ◽  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Dynamic Responses ◽  
Peak Amplitude ◽  
Quantitative Prediction ◽  
Dynamic Features ◽  
Electromechanical Model ◽  
Different Characteristics

A quartz tuning fork and its qPlus configuration show different characteristics in their dynamic features, including peak amplitude, resonance frequency, and quality factor. Here, we present an electromechanical model that comprehensively describes the dynamic responses of an electrically driven tuning fork and its qPlus configuration. Based on the model, we theoretically derive and experimentally validate how the peak amplitude, resonance frequency, quality factor, and normalized capacitance are changed when transforming a tuning fork to its qPlus configuration. Furthermore, we introduce two experimentally measurable parameters that are intrinsic for a given tuning fork and not changed by the qPlus configuration. The present model and analysis allow quantitative prediction of the dynamic characteristics in tuning fork and qPlus, and thus could be useful to optimize the sensors’ performance.

A Quadrature Adaptive Coherent Lock-in Chip-Based Sensor for Accurate Photoacoustic Detection

2020 ◽  
Author(s):  
Zhongyuan Fang ◽  
Chuanshi Yang ◽  
Kai Tang ◽  
Liheng Lou ◽  
Wensong Wang ◽  
...  
Keyword(s):  
Photoacoustic Detection ◽  
Lock In

Precision of lock‐in amplifiers as a function of signal‐to‐noise ratio

1987 ◽  
Vol 58 (2) ◽  
pp. 299-300 ◽  
Author(s):  
D. M. Gualtieri
Keyword(s):  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Lock In
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