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Luminescence dating procedures at the Gliwice Luminescence Dating Laboratory

Moska Piotr, Bluszcz Andrzej, Poręba Grzegorz, Tudyka Konrad, Adamiec Grzegorz, Szymak Agnieszka, Przybyła Aleksandra

Geochronometria

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2021

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Vol. 48, no.1

1--15

EN

The Gliwice Luminescence Laboratory (GLL) is a part of the Institute of Physics – Centre for Science and Education at the Silesian University of Technology, which has gradually evolved since the 1980s. To date, nearly 3500 samples have been dated using luminescence from materials such as ceramics, bricks, and sediments from archaeological and geological sites. Currently, the laboratory is equipped with four luminescence readers and three gamma spectrometers, allowing luminescence dating of approximately 300 samples annually for the needs of research projects. This article focuses on the laboratory procedures used in GLL to obtain luminescence ages. Recent improvements of the GLL's facilities and new equipment, as well as the performance spanning the Laboratory's 30 years of activity, are discussed in terms of obtained results and the involvement in national and international projects.

2

Luminescence dating of Quaternary sediments – some practical aspects

Moska Piotr

Studia Quaternaria

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2019

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Vol. 36, Nr 2

161--169

EN

Luminescence dating is based mainly on the dosimetric properties of quartz and feldspar. These minerals are among the most popular found on Earth, resulting in the possibility of using luminescence methods in practically any environment. Currently, quartz remains the best recognized mineral in terms of dosimetric properties, particularly with regards to results obtained for quartz grains, which are regarded as being the most reliable in luminescence dating. Supporters of luminescence methods are constantly growing, however, these groups do not always have sufficient knowledge to avoid even the most basic of issues that may be encountered overall – from the process of sampling through to the awareness of what a single luminescence result represents. The present paper provides an overview of several practical aspects of luminescence dating such as correct sampling procedures and all necessary information regarding the calculation of the dose rate and equivalent dose with particular reference to potential problems that occur when the age of the sample is being determined. All these aspects are crucial for obtaining a reliable dating result, on the other hand, they remain a potential source of uncertainty.

3

Wpływ algorytmów obliczających rozkłady dawek w radioterapii na prawdopodobieństwo miejscowego wyleczenia

Ślosarek Krzysztof, Stąpór-Fudzińska Małgorzata, Osewski Wojciech, Szlag Marta

Inżynier i Fizyk Medyczny

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2019

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Vol. 8, nr 1

27--32

PL

W planowaniu rozkładu dawki w radioterapii stosowane są różne algorytmy obliczające. Najprostsze z nich, stosowane od wielu lat, dają dobrą zgodność: obliczenia – pomiar, ale tylko w przypadku najprostszych modeli, np. w ośrodku o jednorodnej gęstości. Wraz z rozwojem technik obliczeniowych pojawiły się algorytmy, które uwzględniały coraz więcej zjawisk fizycznych oddziaływania promieniowania z materią. Różnice pomiędzy dawkami obliczonymi i zmierzonymi, dla bardzo wyrafinowanych sytuacji klinicznych, są coraz mniejsze, mieszczą się granicach niepewności metody. Czy zatem dokładność obliczeń może mieć wpływ na wyniki radioterapii? Aby odpowiedzieć na to pytanie, należy rozkłady dawek fizycznych połączyć z dawkami biologicznie równoważnymi i obliczyć prawdopodobieństwo miejscowego wyleczenia. Skorzystano z modelu liniowo-kwadratowego oraz modelu Poissona. Wykonane obliczenia wskazują, że istnieje wpływ algorytmu obliczającego na prawdopodobieństwo miejscowego wyleczenia. Jednak jest on uzależniony od lokalizacji guza nowotworowego. W sytuacji, kiedy różnice gęstości w napromienianej objętości nie są zbyt duże – najprostsze i najbardziej zaawansowane modele wyliczają podobne dawki, czyli nie wykazują wpływu na prawdopodobieństwo miejscowego wyleczenia. Jednak w sytuacji dużych różnic w gęstościach, prostsze modele mogą znacznie zafałszować rozkłady dawek, co przekłada się na TCP.

EN

In the radiotherapy treatment planning, different calculation algorithms are used. Can the accuracy of calculations affect the results of radiotherapy? Physical dose distributions should be combined with biologically equivalent doses and calculated the local control probability. The Linear-Quadratic model and the Poisson model were used. The dose calculations indicates that there is an effect of a computing algorithm on the local control probability. However, it depends on the location of the tumor. In the case of large differences in densities, more simple models can significantly distort dose distribution, which affects the TCP.

4

OSL chronostratigraphy for loess deposits from Tyszowce – Poland

Moska P., Adamiec G., Jary Z., Bluszcz A.

Geochronometria

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2017

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Vol. 44, no. 1

307--318

EN

The presented work concerns a loess profile located in Tyszowce, in the eastern part of Poland on the Volyn Upland, close to the Ukrainian border. The investigated loess formation is well preserved and is characterised by clear stratigraphic units providing an opportunity to refine the loess chronostratigraphy in Poland. In the paper, we present luminescence ages of loess from the last glacial cycle in SE Poland (up to about 100 ka) together with seven radiocarbon ages. Twenty-one samples were collected and dated using infrared (post-IR IRSL) and blue light stimulated luminescence dating. Two fractions were used, namely polymineral fine grains (4–11 μm) and medium sized quartz grains (45–63 μm). The obtained luminescence ages show very good agreement of both methods in relation to loess deposits, however for the fossil soil units the post-IR IRSL method yields older ages. Radiocarbon dates also confirm luminescence chronostratigraphy for younger units. Moreover, the luminescence results are supported by detailed analyses of grain size distribution, carbonate content and magnetic susceptibility variations allowing to create a comprehensive picture of chronological evolution of this site.

5

Międzynarodowe podstawowe normy ochrony przed promieniowaniem i bezpieczeństwa źródeł promieniowania

Musiałowicz T.

Postępy Techniki Jądrowej

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2015

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z. 3

15--22

PL

W artykule omówiono wydaną w roku ubiegłym przez MAEA publikację zawierającą „MIĘDZYNARODOWE PODSTAWOWE NORMY OCHRONY PRZED PROMIENIOWANIEM I BEZPIECZEŃSTWA ŹRÓDEŁ PROMIENIOWANIA”. Odrębnie scharakteryzowano wymagania dotyczące różnych sytuacji narażenia: planowanego narażenia, wyjątkowego narażenia i istniejącego narażenia. W zakończeniu artykułu, jego autor i współautor poprzednich wydań NORM (1967, 1996), przedstawia swoją opinię na temat omawianej publikacji.

EN

New IAEA publication entitled “Radiation Protection and Safety of Radiadion Sources: International Basic Safety Standards”. (No.GSR PART 3 IAEA) was described in the paper. The main parts of that publication concerning different exposure situations: planned exposure, emergency exposure, existing exposure are discussed separately. In the conclusion author of the article and simultaneously co-author of former editions (1967, 1996) of the BESIC SAFETY REQUIREMENTS presents his own opinion on the described book.

6

OSL dating and lithological characteristics of loess deposits from Biały Kościół

Moska P., Adamiec G., Jary Z.

Geochronometria

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2011

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Vol. 38, no. 2

162-171

EN

Absolute dating using luminescence methods is widely applicable in geology, geomor-phology, palaeogeography and in archaeology in establishing ages of sediments and archaeological artefacts. By creating absolute time scales for different events in the history of Earth scientists are able to reconstruct changes in climate and environment in the past, and the history of colonization and development of culture. Grain size is the most important loess lithologic property. Grain size composition depends mainly on factors connected with depositional processes (i.e. variety of source areas, distance from source areas, frequency and intensity of dust transporting winds). The influence of post depositional processes on changes in grain size composition seems to be of less importance with the exceptions for warm and long periods of intensive pedogenesis, which are favorable for formation of clay minerals. Therefore the grain size differentiation within thick loess sections may be used as a proxy record of climate changes during loess cover development. Here we present results for 12 samples dated at the profile at Biały Kościół. Obtained OSL results in some cases are quite different as compared with the OSL and TL dates obtained during last 10 years by other authors and presented in previous publications relating to this loess profile.

7

Effects of feldspar contamination on equivalent dose and the shape of growth curve for osl of silt-sized quartz extracted from Chinese loess

Lai Z., Brückner H.

Geochronometria

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2008

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Vol. 30

49-53

EN

This study examines the effects of feldspar contamination of different extent (by fluorosilicic acid etching for different time periods and mixing pure quartz with different percentage of unetched grains) on blue-light stimulated luminescence (BLSL) of quartz (38-63 µm) for Chinese loess. In particular, the De values and the shape of growth curves will be examined. The results show that: (1) The De determined using feldspar in Chinese loess is obviously underestimated, and infra-red stimulated luminescence (IRSL) has a greater underestimation than BLSL. For aliquots with no fluorosilicic acid etching, an IRSL De underestimation of 󕾎% is observed for a sample with an expected age of 󕾆 ka, 󕾃% underestimation for BLSL, and 󕽺% for post-IR BLSL. For quartz BLSL, the contamination of feldspar, which has not dissolved by fluorosilicic acid etching, will inevitably lead to age underestimation. We suggest that the IR-checking should be performed for every single aliquot. An aliquot should be excluded from the final De calculation if obvious IRSL signal was observed. (2) For the sample under examination blue LED stimulation can reset both IRSL and BLSL signals of feldspars, while IR stimulation cannot reset the BLSL of feldspars. (3) For multiple-mineral aliquot the growth curve shape of the post-IR BLSL is different from that of the IRSL, and within 25 Gy it is identical to that of the pure quartz BLSL. The contamination of feldspars in quartz will change the shape of a growth curve for quartz BLSL.

8

On the detection of OSL age overestimation using single-aliquot techniques

Wallinga J.

Geochronometria

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2002

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Vol. 21

17-26

EN

Optically stimulated luminescence (OSL) dating is a quantitative dating method to determine the time of last exposure of sand and silt to (sun) light. However, insufficient resetting of the optically stimulated luminescence signal prior to sediment deposition can result in overestimation of the age of a sample. Therefore detection of so-called poor bleaching is of prime importance in OSL dating. Several methods proposed in the literature for detection of poor bleaching are based on the scatter in equivalent doses obtained by singlealiquot methods. In this paper numerical simulations are used to assess the validity of these methods. The simulations show that scatter in equivalent doses is largely dependent on the number of grains contributing to the luminescence signal of each aliquot, and proportion of poorly-bleached grains in the mixture under study. Thresholds for detection of poor bleaching based on inter-aliquot scatter in equivalent doses are therefore not valid. It is concluded that tight, symmetrical dose distributions obtained on small aliquots (ultimately consisting of a single grain) provide the best indication that the sample is homogeneously bleached.