A pulsed light-emitting-diode system for stimulation of luminescence

Chithambo, M.L.; Galloway, R.B.

doi:10.1088/0957-0233/11/4/312

Cited by 68 publications

(72 citation statements)

References 15 publications

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“…[1][2][3]. TR-OSL has been measured using pulsed laser [1,4] or LEDs and summing signals from many pulses [5,6]. The time delay between stimulation and luminescence emission can be considered to result from 3 processes, see figure 1: (i) eviction of charge from the trap to the conduction band, (ii) the recombination lifetime (a function of the electron concentration in the conduction band and hole concentration) and (iii) the de-excitation time (lifetime) of the excited state of the recombination centre.…”

Section: Introductionmentioning

confidence: 99%

Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

Tsukamoto¹,

Murray²,

Ankjærgaard³

et al. 2010

J. Phys. D: Appl. Phys.

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Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons. Journal of Physics D: Applied Physics, IOP Publishing, 2010, 43 (32) ABSTRACTA time-resolved optically stimulated exo-electron (TR-OSE) measurement system has been developed using a Photon Timer attached to a gas-flow semi-proportional pancake electron detector within a Risø TL/OSL reader. The decay rate of the exo-electron emission after the stimulation pulse depends on the probability of (1) escape of electrons into the detector gas from the conduction band by overcoming the work function of the material, and (2) thermalisation of electrons in the conduction band, and subsequent re-trapping/recombination.Thus we expect the exo-electron signal to reflect the instantaneous electron concentration in the conduction band. In this study, TR-OSE and TR-OSL were measured for the first time using quartz, K-feldspar and NaCl by stimulating the samples using pulsed blue LEDs at different temperatures between 50 and 250°C after beta irradiation and preheating to 280°C.The majority of TR-OSE signals from all the samples decayed much faster than TR-OSL signals irrespective of the stimulation temperatures. This suggests that the lifetime of OSL in these dosimeters arises mainly from the relaxation of an excited state of the recombination centre, rather than from residence time of an electron in the conduction band.

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Section: Introductionmentioning

confidence: 99%

Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

Tsukamoto¹,

Murray²,

Ankjærgaard³

et al. 2010

J. Phys. D: Appl. Phys.

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“…The physical processes leading up to the emission of luminescence in quartz may be investigated using time-resolved optical stimulation. The aim of this method is to separate in time the stimulation and emission of luminescence to enable measurement of time-resolved luminescence spectra which may be resolved into associated lifetimes, defined in this sense as the delay between stimulation and emission of luminescence [4,5]. A number of such studies show that annealing defines the detailed distribution of lifetimes with measurement temperature as well as the irradiation-dependent characteristics of the lifetimes [3,6].…”

mentioning

confidence: 99%

“…Luminescence was measured using an LED based Pulsing System [4]. The pulses are generated from an integrated circuit multivibrator, a 2N74221, and used to drive a set of LEDs.…”

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confidence: 99%

Relative features of the principal and secondary luminescence lifetimes in quartz

Chithambo

Ogundare

2007

Phys. Status Solidi (c)

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PACS 78.47.+p, 78.55.HxThe form of time-resolved luminescence spectra has been studied for quartz annealed at 800 o C and pulsestimulated at 470 nm. Depending on the measurement temperature and the irradiation dose, the spectra may be de-convolved into two possible components to produce a principal and subsidiary lifetime component. Measurements between 20 and 200 o C show that both components are affected by thermal quenching of the associated luminescence, qualitatively so for the subsidiary one, but with an activation energy of 0.71 eV for the principal lifetime. Regarding influence of irradiation, time-resolved spectra consist of a single component below about 260 Gy but two components thereafter independent of irradiation. The irradiation-dependent features of the lifetimes are accounted for in terms of the relative importance of the various luminescence centers in quartz.1 Introduction Quartz is a common natural mineral with properties that make it amenable for application in radiation dosimetry using luminescence methods [1]. The luminescence properties of quartz including its sensitivity and luminescence lifetimes undergo notable changes when the quartz is annealed, and in particular, near its phase inversion temperatures of 573 and 867 o C [2, 3]. The physical processes leading up to the emission of luminescence in quartz may be investigated using time-resolved optical stimulation. The aim of this method is to separate in time the stimulation and emission of luminescence to enable measurement of time-resolved luminescence spectra which may be resolved into associated lifetimes, defined in this sense as the delay between stimulation and emission of luminescence [4,5]. A number of such studies show that annealing defines the detailed distribution of lifetimes with measurement temperature as well as the irradiation-dependent characteristics of the lifetimes [3,6]. In particular, it was noted [3] that spectra measured at certain temperatures could be accurately resolved into more than one component, a scenario that pointed to the possibility of involvement of multiple luminescence centers in the emission of luminescence from quartz.The aim of this work is to build on the findings described, specifically to study the influence of measurement temperature and irradiation on the principal and subsidiary luminescence lifetimes in natural quartz.

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“…TR-OSL was measured using a light-emitting-diode (LED) based pulsing system [36,37]. In the system, an ORTEC MCS-plus multichannel scaler is used to trigger a set of LEDs at preset repetition rates while simultaneously processing resultant luminescence photon counts from an EMI 9635QA photomultiplier to produce TR-OSL.…”

Section: Measurement Of Time-resolved Luminescence Spectramentioning

confidence: 99%

Time-resolved optically stimulated luminescence and spectral emission features of α-Al2O3:C

Chithambo

Nyirenda

Finch

et al. 2015

Physica B: Condensed Matter

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A pulsed light-emitting-diode system for stimulation of luminescence

Cited by 68 publications

References 15 publications

Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

Charge recombination processes in minerals studied using optically stimulated luminescence and time-resolved exo-electrons

Relative features of the principal and secondary luminescence lifetimes in quartz

Time-resolved optically stimulated luminescence and spectral emission features of α-Al2O3:C

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