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A new quartz for y-transfer calibration of radiation sources

Richter D., Woda C., Dornich K.

Geochronometria

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2020

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Vol. 47, no.1

23--34

EN

Quartz grains extracted from aeolian sand (LexCal2014) are tested for suitability as transfer material for radiation source calibration. After thermal pre-treatment, this quartz exhibits luminescence and dose-response properties which appear appropriate for transfer calibration purposes with little dependence of recovered β-dose on preheat temperature in the single aliquot (SAR) procedure and satisfying performance in β-dose recovery (0.98−1.00 given/measured β-dose for various experiments). Additional support is obtained by SARA and interpolation procedures, where OSL-data from γ-dosed LexCal2014 is interpolated on data obtained for zeroed LexCal2014 quartz, which is β-irradiated by the source to be calibrated. Initial results on fine-grain material agree with the coarse grain results presented. The γ-dose of 3.00 ± 0.07 Gy is administered in a scatter-free geometry at the IAEA/WHO Secondary Standard Dosimetry Laboratory (SSDL) of the Helmholtz Zentrum München, with absorbed dose calculations obtained by Monte Carlo simulations.

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Lexsyg smart — a luminescence detection system for dosimetry, material research and dating application

Richter D., Richter A., Dornich K.

Geochronometria

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2015

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Vol. 42, no.1

202--209

EN

Following the luminescence system lexsyg research, which was designed for research, the luminescence reader lexsyg smart for the application of luminescence detection was developed by Freiberg Instruments. It is suited for routine measurements of luminescence (thermoluminescence, photoluminescence, photon-stimulated, optically stimulated and infrared stimulated luminescence) for a wide range of materials because of the availability of several stimulation sources. The possibility for user definition and change of most parameters provides a great deal of flexibility and also allows research applications. While detection is limited to a single unit and sample storage to 40 positions, the lexsyg smart is much faster in aliquot transportation compared to the lexsyg research, and allows fast mass measurements in luminescence dating, retrospective and personal dosimetry, etc. Cross talk of optical stimulation is absent and cross-irradiation is negligible from the single radioactive source (α, β or x-ray) because of a disconnected sample storage wheel from the measurement chamber, which has a small volume and therefore gas consumption is small. Thermoluminescence measurements and pre-heatings are possible with a versatile heater, which can be programmed for linear/non-linear heating at varying rates and durations for an almost unlimited number of steps. Optical excitation for up to three wavelength bands (violet, blue, green, yellow, infrared) is provided from high power LEDs or laser diodes, with an optional filter wheel to vary detection wavelength bands according the material specific requirements. Either can be programmed to change at almost any time within measurement sequences.

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Lexsyg – a new system for luminescence research

Richter D., Richter A., Dornich K.

Geochronometria

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2013

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Vol. 40, no. 4

220--228

EN

The newly developed lexsyg system by Freiberg Instruments is a versatile luminescence reader, suited for research on the luminescence of materials, fundamental research in luminescence dating, but also for routine mass measurements in retrospective dosimetry as well as in dating application. The 80 sample storage wheel is disconnected from the measurement chamber and therefore crosstalk of optical stimulation is absent and cross-irradiation is negligible from the α- and β-sources, which are providing very uniform irradiations, with the latter especially designed for radiofluorescence (RF) measurement. Optical excitation sources and filter wheels to vary detection wavelengths can be programmed to change at almost any time within measurement sequences, including the auto-mated change of an optional wheel holding up to four different detectors. Thermoluminescence measurements and preheating are possible with a versatile heater, which can be programmed for linear or non-linear heating or cooling, as well as holding a temperature constant. Rates as well as durations can be varied, together with individual ramping, staging and cooling for an almost unlimited number of steps. Violet- and IR-lasers, green and blue LED-arrays can be operated in continuous (CW) or modulated mode (linear/non-linear), and optionally for pulsed as well as time resolved luminescence detection. Six arrays of power LEDs allow the simulation of different bleaching regimes (‘solar simulator’), while luminescence detection can be achieved by a variety of photomultiplier tubes and by CCD cameras for spatially resolved measurements and luminescence spectra.