Have a personal or library account? Click to login
Some novel features of post-500°C heating blue stimulated OSL emission of fired natural quartz Cover

Some novel features of post-500°C heating blue stimulated OSL emission of fired natural quartz

Geochronometria
Volume 44 (2017): Issue 1 (January 2017)
By: Dileep K Koul,  Anuj Soni and  Debabrata Datta  
Open Access
|Nov 2017

Figures & Tables

Fig. 1

OSL decay curves of fired (a) Greek sample, (b) local brick sample (c) Polish sample and (d) Thar dessert samples after 500°C pre-heating (curve ‘A’), bleaching with blue light of RISO system for 100 s (curve ‘B’) and bleaching and 500°C pre-heating (curve ‘C’). The OSL was recorded at a stimulation temperature of 125°C after administering a dose of 200 Gy to the sample. Fresh disc was used for each protocol.

Fig. 2

OSL shine down curves recorded with pre-heating temperatures of 260°C and 500°C (a) sensitization corrected and (b) the corrected curve normalized with the respective initial data point. The OSL in these plots represent fast OSL (OSL measured with pre-heat at 260°C) and DT-OSL (OSL measured with pre-heat at 500°C). In order to understand the decaying nature of DT-OSL, its initial 10 data points are compared with that of fast OSL in the inset of (b). The shine down curves were corrected for sensitization with respective test dose OSL. These curves were recorded after administering a dose of 200 and test dose of 1.5 Gy. All OSL measurements were done at a stimulation temperature of 125°C.

Fig. 3

Component analysis of CW-OSL curves recorded with preheats (a) 260°C and (b) 500°C. The samples were irradiated with the dose oi 200 Gy and the OSL was recorded at a stimulation temperature oi 125°C.

Fig. 4

(a) TL glow curve of the Koupa, Greek, sample recorded after administration of a dose of 200 Gy and heating up to a temperature of 625°C with a heating rates 2°C/s. The inset in the Fig. 2a shows the high temperatures peaks in a better way by plotting the data in linearlog scale. (b) to have a better feel of the 5l0°C TL glow peak, it was recorded after thermal cleaning of the glow curve by heating the sample up to 475°C.

Fig. 5

(a) Sensitization corrected 510°C TL glow peak of Greek sample with and without bleaching treatment. Prior to the TL measurement the sample was heated up to 475°C to remove the traps lower than this glow peak. Heating in both cases, TL measurement and preheating, was done with heating rate of 2°C/s. The bleaching was done for 100 s using the blue light of the Riso system at a stimulation temperature of 125°C. The glow curves were measured with a radiation dose of200 Gy and sensitization corrected with a test dose OSL of 1.5 Gy.

Fig. 6

(a) Plot of sensitization corrected OSL shine down curves as a function of pre-heating temperatures (the inset depicting the uncorrected curves), (b) TL glow curves recorded during pre-heating of 475, 525, 575 and 625°C, applied prior to OSL measurement and (c) pulse annealing curves; plots of sensitization corrected fast OSL signal as a function of pre-heating temperatures, the inset shows a comparison of the sensitization corrected and un-corrected pulse annealing curves. The signal was represented by the sum of counts in the initial 5 channels (2.5 s) minus the sum of counts in the final 5 s of the shine down curve. The sensitization correction was done with a test dose OSL signal. A radiation dose of 100 Gy and a test dose of 1.5 Gy were employed in this measurement. The TL glow curves were recorded with a heating rate of 2°C/s and OSL was recorded at a stimulation temperature of 125°C.

Fig. 7

Impact of bleaching on DT-OSL signal with bleaching time periods of 0, 2, 10, 20, 50 and 100 s using blue light of Riso system. The sample was irradiated with a dose of 150 Gy and the bleached at a stimulation temperature of 125°C. The signal was represented by the sum of counts in the initial 5 channels (2.5 s) minus the sum of counts in the final 5 s of the shine down curve. The signal was corrected with a test dose OSL. A dose of 150 Gy was administered to the sample prior to each optical stimulation and a test dose of 5 Gy was used for sensitization correction.

Fig. 8

The plot of sensitization corrected signals corresponding to (a) deep trap OSL (DT-OSL) and fast OSL with dose administered up to a dose of 1000 and 600 Gy respectively and (b) only DT-OSL up to highest administered dose value of 10 kGy, the inset in this figure shows plot of the data till a dose of 1 kGy. Since the fast OSL saturated much early than the DT-OSL, so, its growth curve was measured up to 600 Gy only. The data of the two curves in (a) was normalized in such a way that the data points of the two curves corresponding to 600 Gy matched with each other. The protocol involved pre-heats of 260 and 500°C for measurements of fast OSL and DT-OSL respectively and a cut heat of 160°C. The data in DT-OSL could be fitted with a linear fit till a dose of 1 kGy. and latter beyond it till the last administered dose of 2.5 kGy, as shown in (b). The signal was represented by the sum of counts in the initial 5 channels (2.5 s) minus the sum of counts in the final 5 s of the shine down curve. These curves were measured at a stimulation temperature of 125°C.

Fig. 9

The reproducibility of DT-OSL was undertaken by observing its four repeated sensitization corrected measurements with the same dose value of 100 Gy and then repeating it once more with the same dose, but, after a measurement with administration of a zero dose, i.e. no dose, (run number 5). A test dose of 3 Gy was used in this observation. The measurement was done with a pre-heat and cut-heat of 500 and 160°C respectively. The signal was represented by the sum of counts in the initial 5 channels (2.5 s) minus the sum of counts in the final 5 s of the shine down curve. These curves were measured at a stimulation temperature of 125°C.

Fig. 10

The variation in luminescence sensitization during different runs of the SAR. The data represents the average values of the three discs which were administered an identical dose of 200 Gy, i.e. the dose to be recovered. The regenerative doses used in the protocol were 100, 300 and 400 Gy. A test dose of 1.5 Gy and cut heat of 160°C was incorporated in the measurement. The protocol was modified in terms of pre-heating temperature, a heating at 500°C, without holding it for anytime.

Protocol to record the thermal pulse annealing of deep trap_

StepTreatment
1Administer a radiation dose of 100 Gy
2Heat at different temperatures starting with 450°C (Pre-heat)
3Stimulate for 100 s at 125°C to record OSL, Lx
4Administer a test dose of 1.5 Gy
5Heat at 160°C for 10 s (Cut- heat)
6Stimulate for 100 s at 125°C to record OSL, Tx
7Repeat the steps from 1 to 6 using various pre-heating temperature up to 625°C in steps of 25°C
DOI: https://doi.org/10.1515/geochr-2015-0078 | Journal eISSN: 1897-1695
Journal RSS Feed
Language: English
Page range: 287 - 298
Submitted on: Feb 14, 2017
|
Accepted on: Sep 8, 2017
|
Published on: Nov 23, 2017
Published by: Sciendo
In partnership with: Paradigm Publishing Services
Publication frequency: 1 issue per year
Keywords:
deep traps,
quartz,
OSL
Related subjects:
Geosciences,
Geosciences, other

© 2017 Dileep K Koul, Anuj Soni, Debabrata Datta, published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Previous articleVolume 44 (2017): Issue 1 (January 2017)Next article