The Experts below are selected from a list of 1797 Experts worldwide ranked by ideXlab platform
Juha Kostamovaara - One of the best experts on this subject based on the ideXlab platform.
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a 16 times256 spad line detector with a 50 ps 3 bit 256 channel time to digital converter for raman spectroscopy
IEEE Sensors Journal, 2018Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, David Stoppa, Juha KostamovaaraAbstract:A $16\times256$ element single-photon avalanche diode array with a 256-channel, 3-bit on-chip time-to-digital converter (TDC) has been developed for fluorescence-suppressed Raman spectroscopy. The circuit is fabricated in $0.35~\mu \text{m}$ high-voltage CMOS technology and it allows a measurement rate of 400 kframe/s. In order to be able to separate the Raman and fluorescence photons even in the presence of the unavoidable timing skew of the timing signals of the TDC, the time-of-arrival of every detected photon is recorded with high time resolution at each spectral point with respect to the emitted short and intensive laser pulse (~150 ps). The dynamic range of the TDC is set so that no Raman photon is lost due to the timing skew, and thus the complete time history of the detected photons is available at each spectral point. The resolution of the TDC was designed to be adjustable from 50 ps to 100 ps. The error caused by the timing skew and the residual variation in the resolution of the TDC along the spectral points is mitigated utilizing a calibration measurement from reference sample with known smooth fluorescence spectrum. As a proof of concept, the Raman spectrum of Sesame Seed Oil, having a high fluorescence-to-Raman ratio and a short fluorescence lifetime of 1.9 ns, was successfully recorded.
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on the effects of the time gate position and width on the signal to noise ratio for detection of raman spectrum in a time gated cmos single photon avalanche diode based sensor
Sensors and Actuators B-chemical, 2017Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, Juha KostamovaaraAbstract:Abstract The effects of the position and width of the time gate on the available signal-to-noise ratio in a time-gated Raman spectrometer are analyzed and measured. The Raman spectrometer used is based on a high power, 532 nm, pulsed laser (500 ps FWHM) and a time-resolving circuit with a single photon avalanche diode (SPAD) detector which is moved by a microstep motor to derive the whole Raman spectrum. The times of arrival of the scattered photons are recorded and the effectiveness of different time gate positions and widths are analyzed by post-processing the measured and simulated data. It is shown from measurements performed on olive and Sesame Seed Oil samples having fluorescence lifetimes of 2.5 ns and 2 ns and Raman-to-fluorescence photon ratios of 0.03 and 0.003, respectively, that the fluorescence background can be substantially suppressed if the width and position of the time gate are properly selected.
Ilkka Nissinen - One of the best experts on this subject based on the ideXlab platform.
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Timing Skew Compensation Methods for CMOS SPAD Line Sensors Used for Raman Spectroscopy
2019 IEEE SENSORS, 2019Co-Authors: Tuomo Talala, Ilkka NissinenAbstract:Two methods were developed to compensate for the timing skew of CMOS SPAD line sensors used for time-resolving Raman spectroscopy. Both methods were tested using a time-resolving Raman spectrometer built around a 256-channel CMOS SPAD line sensor. As an example, Raman spectrum of highly fluorescent Sesame Seed Oil was measured. Most of the distortion in the measured spectrum was caused by the timing skew and about 75 % of it could be removed by using either of the methods presented.
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a 16 times256 spad line detector with a 50 ps 3 bit 256 channel time to digital converter for raman spectroscopy
IEEE Sensors Journal, 2018Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, David Stoppa, Juha KostamovaaraAbstract:A $16\times256$ element single-photon avalanche diode array with a 256-channel, 3-bit on-chip time-to-digital converter (TDC) has been developed for fluorescence-suppressed Raman spectroscopy. The circuit is fabricated in $0.35~\mu \text{m}$ high-voltage CMOS technology and it allows a measurement rate of 400 kframe/s. In order to be able to separate the Raman and fluorescence photons even in the presence of the unavoidable timing skew of the timing signals of the TDC, the time-of-arrival of every detected photon is recorded with high time resolution at each spectral point with respect to the emitted short and intensive laser pulse (~150 ps). The dynamic range of the TDC is set so that no Raman photon is lost due to the timing skew, and thus the complete time history of the detected photons is available at each spectral point. The resolution of the TDC was designed to be adjustable from 50 ps to 100 ps. The error caused by the timing skew and the residual variation in the resolution of the TDC along the spectral points is mitigated utilizing a calibration measurement from reference sample with known smooth fluorescence spectrum. As a proof of concept, the Raman spectrum of Sesame Seed Oil, having a high fluorescence-to-Raman ratio and a short fluorescence lifetime of 1.9 ns, was successfully recorded.
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on the effects of the time gate position and width on the signal to noise ratio for detection of raman spectrum in a time gated cmos single photon avalanche diode based sensor
Sensors and Actuators B-chemical, 2017Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, Juha KostamovaaraAbstract:Abstract The effects of the position and width of the time gate on the available signal-to-noise ratio in a time-gated Raman spectrometer are analyzed and measured. The Raman spectrometer used is based on a high power, 532 nm, pulsed laser (500 ps FWHM) and a time-resolving circuit with a single photon avalanche diode (SPAD) detector which is moved by a microstep motor to derive the whole Raman spectrum. The times of arrival of the scattered photons are recorded and the effectiveness of different time gate positions and widths are analyzed by post-processing the measured and simulated data. It is shown from measurements performed on olive and Sesame Seed Oil samples having fluorescence lifetimes of 2.5 ns and 2 ns and Raman-to-fluorescence photon ratios of 0.03 and 0.003, respectively, that the fluorescence background can be substantially suppressed if the width and position of the time gate are properly selected.
Jan Nissinen - One of the best experts on this subject based on the ideXlab platform.
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a 16 times256 spad line detector with a 50 ps 3 bit 256 channel time to digital converter for raman spectroscopy
IEEE Sensors Journal, 2018Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, David Stoppa, Juha KostamovaaraAbstract:A $16\times256$ element single-photon avalanche diode array with a 256-channel, 3-bit on-chip time-to-digital converter (TDC) has been developed for fluorescence-suppressed Raman spectroscopy. The circuit is fabricated in $0.35~\mu \text{m}$ high-voltage CMOS technology and it allows a measurement rate of 400 kframe/s. In order to be able to separate the Raman and fluorescence photons even in the presence of the unavoidable timing skew of the timing signals of the TDC, the time-of-arrival of every detected photon is recorded with high time resolution at each spectral point with respect to the emitted short and intensive laser pulse (~150 ps). The dynamic range of the TDC is set so that no Raman photon is lost due to the timing skew, and thus the complete time history of the detected photons is available at each spectral point. The resolution of the TDC was designed to be adjustable from 50 ps to 100 ps. The error caused by the timing skew and the residual variation in the resolution of the TDC along the spectral points is mitigated utilizing a calibration measurement from reference sample with known smooth fluorescence spectrum. As a proof of concept, the Raman spectrum of Sesame Seed Oil, having a high fluorescence-to-Raman ratio and a short fluorescence lifetime of 1.9 ns, was successfully recorded.
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on the effects of the time gate position and width on the signal to noise ratio for detection of raman spectrum in a time gated cmos single photon avalanche diode based sensor
Sensors and Actuators B-chemical, 2017Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, Juha KostamovaaraAbstract:Abstract The effects of the position and width of the time gate on the available signal-to-noise ratio in a time-gated Raman spectrometer are analyzed and measured. The Raman spectrometer used is based on a high power, 532 nm, pulsed laser (500 ps FWHM) and a time-resolving circuit with a single photon avalanche diode (SPAD) detector which is moved by a microstep motor to derive the whole Raman spectrum. The times of arrival of the scattered photons are recorded and the effectiveness of different time gate positions and widths are analyzed by post-processing the measured and simulated data. It is shown from measurements performed on olive and Sesame Seed Oil samples having fluorescence lifetimes of 2.5 ns and 2 ns and Raman-to-fluorescence photon ratios of 0.03 and 0.003, respectively, that the fluorescence background can be substantially suppressed if the width and position of the time gate are properly selected.
Pekka Keranen - One of the best experts on this subject based on the ideXlab platform.
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a 16 times256 spad line detector with a 50 ps 3 bit 256 channel time to digital converter for raman spectroscopy
IEEE Sensors Journal, 2018Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, David Stoppa, Juha KostamovaaraAbstract:A $16\times256$ element single-photon avalanche diode array with a 256-channel, 3-bit on-chip time-to-digital converter (TDC) has been developed for fluorescence-suppressed Raman spectroscopy. The circuit is fabricated in $0.35~\mu \text{m}$ high-voltage CMOS technology and it allows a measurement rate of 400 kframe/s. In order to be able to separate the Raman and fluorescence photons even in the presence of the unavoidable timing skew of the timing signals of the TDC, the time-of-arrival of every detected photon is recorded with high time resolution at each spectral point with respect to the emitted short and intensive laser pulse (~150 ps). The dynamic range of the TDC is set so that no Raman photon is lost due to the timing skew, and thus the complete time history of the detected photons is available at each spectral point. The resolution of the TDC was designed to be adjustable from 50 ps to 100 ps. The error caused by the timing skew and the residual variation in the resolution of the TDC along the spectral points is mitigated utilizing a calibration measurement from reference sample with known smooth fluorescence spectrum. As a proof of concept, the Raman spectrum of Sesame Seed Oil, having a high fluorescence-to-Raman ratio and a short fluorescence lifetime of 1.9 ns, was successfully recorded.
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on the effects of the time gate position and width on the signal to noise ratio for detection of raman spectrum in a time gated cmos single photon avalanche diode based sensor
Sensors and Actuators B-chemical, 2017Co-Authors: Ilkka Nissinen, Jan Nissinen, Pekka Keranen, Juha KostamovaaraAbstract:Abstract The effects of the position and width of the time gate on the available signal-to-noise ratio in a time-gated Raman spectrometer are analyzed and measured. The Raman spectrometer used is based on a high power, 532 nm, pulsed laser (500 ps FWHM) and a time-resolving circuit with a single photon avalanche diode (SPAD) detector which is moved by a microstep motor to derive the whole Raman spectrum. The times of arrival of the scattered photons are recorded and the effectiveness of different time gate positions and widths are analyzed by post-processing the measured and simulated data. It is shown from measurements performed on olive and Sesame Seed Oil samples having fluorescence lifetimes of 2.5 ns and 2 ns and Raman-to-fluorescence photon ratios of 0.03 and 0.003, respectively, that the fluorescence background can be substantially suppressed if the width and position of the time gate are properly selected.
Bertrand Matthäus - One of the best experts on this subject based on the ideXlab platform.
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Bioactive compounds and “in vitro” antioxidant activity of some traditional and non-traditional cold-pressed edible Oils from Macedonia
Journal of Food Science and Technology, 2018Co-Authors: Sanja Kostadinović Veličkovska, Sasa Mitrev, Augustin Catalin Moţ, Rubin Gulaboski, Ludger Brühl, Hamed Mirhosseini, Radu Silaghi-dumitrescu, Bertrand MatthäusAbstract:The bioactive compounds and “in vitro” antioxidant activity measured by three antioxidant assays of some traditional and non-traditional cold-pressed edible Oils from Macedonia were object of this study. The fatty acid composition showed dominance of monounsaturated oleic acid in “sweet” and “bitter” apricot kernel Oils with percentages of 66.7 ± 0.5 and 57.8 ± 0.3%, respectively. The most dominant fatty acid in paprika Seed Oil was polyunsaturated linoleic acid with abundance of 69.6 ± 2.3%. The most abundant tocopherol was γ-tocopherol with the highest quantity in Sesame Seed Oil (57.6 ± 0.1 mg/100 g Oil). Paprika Seed Oil, Sesame Seed Oil and sweet apricot Oil were the richest source of phytosterols. DPPH assay was the most appropriate for the determination of the antioxidant activity of cold-pressed sunflower Oil due to high abundance of α-tocopherol with a level of 22.8 ± 1.1 mg/100 g of Oil. TEAC assay is the best for the determination of the antioxidant activity of Sesame Seed Oil and paprika Seed Oils as the richest sources of phenolic compounds. β-carotene assay was the most suitable assay for Oils obtained from high pigmented plant material. Triacylglycerols and phytosterol profiles can be used as useful markers for the origin, variety and purity of the Oils.