scholarly journals Experimental Study on Km-Range Long-Distance Measurement Using Silicon Photomultiplier Sensor with Low Peak Power Laser Pulse

2021 ◽  
Vol 11 (1) ◽  
pp. 403
Author(s):  
Can Candan ◽  
Mehmet Tiken ◽  
Halil Berberoglu ◽  
Elif Orhan ◽  
Aydin Yeniay

Silicon photomultipliers (SiPM) have drawn considerable attention due to their superior sensitivity with a multi-pixel matrix structure. SiPM can be the choice of a detector for time of flight measurement which is one of the most promising applications in the field of light detection and ranging (LiDAR). In this work, we take advantage of SiPM and attempt to measure longer distances with a low peak power semiconductor laser under outdoor sunny and windy conditions. We achieved a long detection range of a few kilometers by using SiPM and a laser with a pulse energy of 9 µj at 0.905 µm and 3 dB enhancement in signal to noise ratio (SNR) by the implemented signal extraction algorithm. From the simulation performed, the minimum SNR value and detection probability were also determined for the outdoor field tests.


Author(s):  
Wenjun Huo ◽  
Peng Chu ◽  
Kai Wang ◽  
Liangting Fu ◽  
Zhigang Niu ◽  
...  

In order to study the detection methods of weak transient electromagnetic radiation signals, a detection algorithm integrating generalized cross-correlation and chaotic sequence prediction is proposed in this paper. Based on the dual-antenna test and cross-correlation information estimation method, the detection of aperiodic weak discharge signals under low signal-to-noise ratio is transformed into the estimation of periodic delay parameters, and the noise is reduced at the same time. The feasibility of this method is verified by simulation and experimental analysis. The results show that under the condition of low signal-to-noise ratio, the integrated method can effectively suppress the influence of 10 noise disturbances. It has a high detection probability for weak transient electromagnetic radiation signals, and needs fewer pulse accumulation times, which improves the detection efficiency and is more suitable for long-distance detection of weak electromagnetic radiation sources.



Author(s):  
Siti Nur Fatin Zuikafly ◽  
Nor Farhah Razak ◽  
Rizuan Mohd Rosnan ◽  
Sulaiman Wadi Harun ◽  
Fauzan Ahmad

In this work, a Graphene slurry based passive Q-switcher fabricated from Graphene-Polylactic acid (PLA) filament which is used for 3D printing. To produce the Graphene slurry, the diameter of the filament was reduced and Tetrahydrofuran (THF) was used to dissolve the PLA. The Graphene-THF suspension was drop cast to the end of a fiber ferrule and the THF then evaporated to develop Graphene slurry based SA which is integrated in fiber laser cavity. At threshold input pump power of 30.45 mW, a Q-switched Erbium-doped fiber laser (EDFL) can be observed with the wavelength centered at 1531.01 nm and this remained stable up to a pump power of 179.5 mW. As the pump power was increased gradually, an increase in the repetition rates was recorded from 42 kHz to 125 kHz, while the pulse width was reduced to 2.58 μs from 6.74 μs. The Q-switched laser yielded a maximum pulse energy and peak power of 11.68 nJ and 4.16 mW, respectively. The proposed Graphene slurry based saturable absorber also produced a signal-to-noise ratio of 44 dB indicating a stable Q-switched pulsed laser.





2020 ◽  
Vol 41 (2) ◽  
pp. 209-214
Author(s):  
Saliha Kheris ◽  
Badra Bouabdallah

AbstractIn this paper, we have presented a global study of simple bonds, focusing on the main limitations introduced by different optical components as laser source, fiber, optical amplifier, and optical detector. The construction of a long-distance link requires the compensation of attenuation and chromatic dispersion phenomena. Thus, it is well known that the attenuations cause the drop of the signal intensity, whereas the pulse spreading, due to the dispersion, causes the increase of the Bit Error Rate (BER) and consequently the reduction of the signal to noise ratio (SNR). In this purpose, we have calculated the quality factor (Q) issues from the noisy signal’s simulations. We have found a Q of 7.02 to a BER of 0.8 e−12. The founding results match well with fixes norms in telecommunication field.



2016 ◽  
Vol 9 (2) ◽  
pp. 829-839 ◽  
Author(s):  
Juha Vierinen ◽  
Jorge L. Chau ◽  
Nico Pfeffer ◽  
Matthias Clahsen ◽  
Gunter Stober

Abstract. The concept of a coded continuous wave specular meteor radar (SMR) is described. The radar uses a continuously transmitted pseudorandom phase-modulated waveform, which has several advantages compared to conventional pulsed SMRs. The coding avoids range and Doppler aliasing, which are in some cases problematic with pulsed radars. Continuous transmissions maximize pulse compression gain, allowing operation at lower peak power than a pulsed system. With continuous coding, the temporal and spectral resolution are not dependent on the transmit waveform and they can be fairly flexibly changed after performing a measurement. The low signal-to-noise ratio before pulse compression, combined with independent pseudorandom transmit waveforms, allows multiple geographically separated transmitters to be used in the same frequency band simultaneously without significantly interfering with each other. Because the same frequency band can be used by multiple transmitters, the same interferometric receiver antennas can be used to receive multiple transmitters at the same time. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large-scale multi-static network of meteor radar transmitters and receivers. Such a system would be useful for increasing the number of meteor detections to obtain improved meteor radar data products.



2008 ◽  
Vol 29 (4) ◽  
pp. 288-296 ◽  
Author(s):  
Jessica S. Yuan ◽  
Yao O. Li ◽  
Judy W. Ue ◽  
Annie S. Wesley ◽  
Levente L. Diosady

Background Efficacy studies have shown that salt double-fortified with iodine and iron can significantly reduce the incidence rates of iron-deficiency anemia and iodine-deficiency disorders. Double-fortified salt can be prepared by mixing microencapsulated iron compounds into conventionally iodated salt. Effective implementation of a double fortification program requires field-based analytical methods to ensure iron levels in double-fortified salt. Objective To develop semiquantitative and qualitative field test kits by adopting standard analytical methods for iron determination to the analysis of iron in double-fortified salt. Methods Thermal, mechanical, and chemical strategies were assessed to enable contact between analytical reagents and the encapsulated iron compounds during the analysis. A chemical approach using nonpolar solvents was adopted in semiquantitative and qualitative field tests. The fat coating of the iron premix was removed by solvents, releasing the iron for subsequent colorimetric determination. Results Both semiquantitative and qualitative field tests were based on initial removal of the microencapsulant, followed by iron quantitation. Solvent dissolution of the coating layer was most useful for rapid release of iron. A semiquantitative field test kit was developed using a mixture of 5% heptane and 95% tetrachloroethylene to free the iron, which was then determined by the 1,10-phenanthroline method. The field test had a useful detection range of 0 to 2,000 ppm of iron. Statistical analyses revealed that the results obtained with the kit correlated well with those obtained by standard laboratory methods ( p < .001). A qualitative field test kit was developed to identify the presence of iron. Microencapsulated iron was freed with the use of tetrachloroethylene and then reacted with phenanthroline to form a visually observable coloration on the salt sample. Conclusion Semiquantitative and qualitative field test kits for iron determination in double-fortified salt have been developed and tested. These kits could be useful in quality control of double fortification of salt in small salt-production facilities and in the field, particularly in developing countries.



2019 ◽  
Vol 64 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Taha Haddadifam ◽  
Mohammad Azim Karami

Abstract Digital silicon photomultiplier (dSiPM) is introduced for diffuse optical imaging (DOI) applications instead of conventional photomultiplier tubes and avalanche photodiodes (APDs) as a state-of-the-art detector. According to the low-level light regime in DOI applications, high sensitivity and high dynamic range (DR) image sensors are needed for DOI systems. dSiPM is proposed as a developing detector which can detect low-level lights. Also, an accurate equation is obtained for calculating the DR of dSiPMs. Different dSiPMs and the corresponding benefits are studied for DOI applications. Furthermore, a 120 dB DR dSiPM is chosen for use in DOI systems. It is shown that dSiPMs can be utilized in DOI configurations such as time domain (TD), frequency domain (FD) and continuous wave (CW) systems. Ultimately, by utilizing dSiPM in DOI systems, the DOI method can be used for thoracic imaging due to the high DR and signal-to-noise ratio (SNR) of the detector.



2020 ◽  
Vol 225 ◽  
pp. 03008
Author(s):  
C.D.R. Azevedo ◽  
A. Baeza ◽  
M. Brás ◽  
T. Cámara ◽  
C. Cerna ◽  
...  

Tritium is released abundantly to the environment by nuclear power plants (NPP), as a product of neutron capture by hydrogen and deuterium. In normal running conditions, released cooling waters may contain levels of tritium close to or even larger than the maximum authorised limit for human consumption (drinking and irrigation). The European Council Directive 2013/51/Euratom requires a maximum level of tritium in water for human consumption lower than 100 Bq=L. Current monitoring of tritium activity in water by liquid scintillating method takes about two days and can only be carried out in a dedicated laboratory. This system is not appropriate for real time monitoring. At present, there exists no available detector device with enough sensitivity to monitor waters for human consumption with high enough sensitivity. The goal of the TRITIUM project is to build a tritium monitor capable to measure tritium activities with detection limit close to 100Bq=L, using instrumentation technique developed in recent years for Nuclear and Particle Physics, such as scintillating fibres and silicon photomultipliers (SiPM). In this paper the current status of the TRITIUM project is presented and he results of first prototypes are discussed. A detector system based on scintillating fibers read out either photomultiplier tubes (PMTs) or silicon photomultiplier (SiPM) arrays is under development and will be installed in the vicinity of Almaraz nuclear power plant (Cáceres, Spain) by the fourth term of 2019.



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