Transient digitizer for the determination of microsecond luminescence lifetimes

Woods, R. J.; Scypinski, Stephen; Love, L. J. Cline.

doi:10.1021/ac00272a043

Cited by 116 publications

(67 citation statements)

References 16 publications

(14 reference statements)

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“…Taking the thickness of the sensing layer (30 m) and the spatial resolution of the imaging system into account, the spatial resolution of the oxygen images was 40 ϫ 40 m pixel Ϫ1 . In order to determine the distribution of oxygen concentrations, the two-dimensional luminescence lifetime distributions were evaluated by the rapid lifetime determination (RLD) method (Woods et al 1984;Ballew and Demas 1989;Liebsch et al 2000). Further image processing was carried out with a custom-made computer program (Holst and Grunwald 2001).…”

Section: Methodsmentioning

confidence: 99%

Oxygen dynamics in permeable sediments with wave‐driven pore water exchange

Precht

Franke

Polerecký

et al. 2004

Limnology & Oceanography

225

169

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The effects of advective pore water exchange driven by shallow water waves on the oxygen distribution in a permeable (k ϭ 3.3 ϫ 10 Ϫ12 to 4.9 ϫ 10 Ϫ11 m 2 ) natural sediment were studied with a planar oxygen optode in a wave tank. Our experiments demonstrate that pore water flow driven by the interaction of sediment topography and oscillating boundary flow changes the spatial and temporal oxygen distribution in the upper sediment layer. Oxygenated water intruding in the ripple troughs and deep anoxic pore water drawn to the surface under the ripple crests create an undulating oxic-anoxic boundary within the upper sediment layer, mirroring the topographical features of the sediment bed. Anoxic upwelling zones under ripple crests can separate the oxic sediment areas of neighboring ripple troughs with steep horizontal oxygen concentration gradients. The optode showed that migrating wave ripples are trailed by their pore water flow field, alternately exposing sediment volumes to oxic and anoxic pore water, which can be a mechanism for remobilizing particulate oxidized metal precipitates and for promoting coupled nitrification-denitrification. More rapid ripple migration (experimental threshold ϳ20 cm h Ϫ1) produces a continuous oxic surface layer that inhibits the release of reduced substances from the bed, which under slowly moving ripples is possible through the anoxic vertical upwelling zones. Swift, dramatic changes in oxygen concentration in the upper layers of permeable seabeds because of surface gravity waves require that sediment-dwelling organisms are tolerant to anoxia or highly mobile and enhance organic matter mineralization.The dominant boundary layer flows in shallow marine environments are those generated by surface gravity waves. This dominance is reflected by the presence of wave ripples structuring large areas of shallow sandy seabeds that are abundant in coastal, estuarine, and shelf environments. Most of these sandy sediments are permeable (k Ͼ 10 Ϫ12 m 2 ) and thus allow interstitial water motion. Pressure differences at the sediment-water interface might drive interfacial solute transport through the surface layers of these beds. This advective transport can exceed transport by molecular diffusion by several orders of magnitude (Huettel and Webster 2001). In contrast, the major transport mechanisms in fine-grained muddy sediments are molecular diffusion and locally bioturbation (Berner 1980;Aller 1982).Increased fluid exchange between sediment and overlying water affects the oxygen dynamics in permeable sediments and therefore also affects biogeochemical processes. Booij 1 Corresponding author (eprecht@mpi-bremen.de). 2 Present address: Florida State University, Department of Oceanography, Tallahassee, FL 32306-4320. AcknowledgmentsBo Barker Jørgensen is acknowledged for support and constant interest in this work. Hans Røy is thanked for initial discussions, helpful comments, and help during fieldwork. For assistance with the planar oxygen optodes, Gerhard Holst and Björn Grunwald are a...

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Section: Methodsmentioning

confidence: 99%

Oxygen dynamics in permeable sediments with wave‐driven pore water exchange

Precht

Franke

Polerecký

et al. 2004

Limnology & Oceanography

225

169

View full text Add to dashboard Cite

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“…The FLI scheme that most closely compares to DIME would be dual gain curve detection analyzed by the standard rapid lifetime determination (SRLD) routine, as proposed by Ashworth and associates [18] and the further developed optimized rapid lifetime determination algorithm (ORLD) presented by Chan et al [30]. All three experimental approaches are applicable in wide-field imaging that could be used for single-shot measurements with data analysis in the temporal domain.…”

Section: Discussionmentioning

confidence: 99%

“…In the temporal domain, Ni and Melton [9] performed single-laser shot measurements with a shortest presented lifetime of 14 ns, which is roughly 2-3 times longer than what typically is of interest [2][3][4][5][6][7][8]11], and they had to use an FL-to-signal intensity calibration curve to evaluate the data. In a follow-up paper, Ni and Melton used the SRLD algorithm proposed by Ashworth and associates [18] to determine the fluorescence lifetime. However, this time measured lifetimes were longer than 30 ns [10].…”

Section: Introductionmentioning

confidence: 99%

Single-laser shot fluorescence lifetime imaging on the nanosecond timescale using a Dual Image and Modeling Evaluation algorithm

Ehn¹,

Johansson²,

Arvidsson³

et al. 2012

Opt. Express

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“…The online decay time estimation is first used to process the waveform and second to control the hardware settings of the following acquisition. The decay time is estimated using Ashworth's rapid decay time determination (RLD) algorithm [3][4][5], that is only temporarily used in the calibration routine. The RLD algorithm is characterized by its shorter computational time and comparable accuracy compared to nonlinear least squares algorithms.…”

Section: Softwarementioning

confidence: 99%

On the automation of thermographic phosphor calibration

Nada

Knappe

et al. 2014

IET &Amp; ISA 60th International Instrumentation Symposium 2014

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Thermographic phosphors can be robust temperature remote sensors. The accuracy of the temperature measured by the phosphor is highly dependent on the quality of the phosphor calibration used. Conventionally, thermographic phosphors are calibrated by measuring a series of decay curves at known stable oven temperatures. The process is then repeated covering the thermal sensitivity range of the phosphor chosen. Heating and cooling rates of high temperature ovens are usually low. Also, thermal equilibrium of the system is required at each calibration temperature before acquiring luminescence decay curves. Thus, the process is usually time consuming and the number of calibration points achieved is limited to a couple of dozen points. This study presents and validates the development of an automatic routine for the calibration of thermographic phosphors. It was designed to continuously and simultaneously acquire phosphor decay curves along with their corresponding thermocouple temperatures. The developed routine required software and hardware improvements. An updated design of the calibration substrate was implemented to improve the thermal conditions during calibration. Thermal gradients were further studied using a heat transfer model. The routine implemented a specially designed sparsing algorithm that reduced the sampling rate of the decaying luminescence curve without influencing the calculated decay time. The upper heating rate is set at 4 K.min -1 due to limitation imposed by the ceramic calibration oven. The phosphors CdWO 4 and Mg 3 F 2 GeO 4 :Mn were chosen to validate the finalized routine. After the completion of the calibration process, a library-based calibration is created as the final product. The automated calibration routine delivered an overall accuracy improvement of 1-2 K, reduced calibration duration by factor of four and provided the possibility of deriving signal recognition algorithms. The condensed calibration dataset produced by the proposed calibration routine was further employed to develop a novel signal shape recognition algorithm for temperature evaluation.

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Transient digitizer for the determination of microsecond luminescence lifetimes

Cited by 116 publications

References 16 publications

Oxygen dynamics in permeable sediments with wave‐driven pore water exchange

Oxygen dynamics in permeable sediments with wave‐driven pore water exchange

Single-laser shot fluorescence lifetime imaging on the nanosecond timescale using a Dual Image and Modeling Evaluation algorithm

On the automation of thermographic phosphor calibration

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