Wyniki wyszukiwania - BazTech

1

New trends in clinical and retrospective dosimetry

Jung Aleksandra, Matusiak Katarzyna

Bio-Algorithms and Med-Systems

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2023

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Vol. 19, no. 1

69--73

EN

Selecting the proper dosimeter and methodology is crucial for accurate dose measurement, especially since the requirements are different for clinical and retrospective dosimetry. Regardless of the field-radiotherapy, X-ray diagnostic radiology or nuclear medicineefforts are continuously being made to improve radiation measurement accuracy through the development of new dosimeters, accurate calibration of instrumentation, training of staff, proper quality control and enhancement of radiation safety procedures. For instance, for retrospective dose estimation during radiation accidents, the selection of the appropriate material and knowledge of the intrinsic background signal of the selected material are crucial. In both clinical and retrospective dosimetry it is important to have adequate protocols as well as expertise in possible uncertainties, discussed here based on the authors own research.

2

Investigating the filling state of OSL detector traps with the optical sampling method

Mandowska Ewa, Smyka Robert, Mandowski Arkadiusz

Metrology and Measurement Systems

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2022

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Vol. 29, nr 2

361--371

EN

Optically stimulated luminescence (OSL) and thermoluminescence (TL) methods are commonly used in dosimetry of ionizing radiation and dating of archaeological and geological objects. A typical disadvantage of OSL detectors is signal loss over a longer time scale. In this article, we present a method of studying this phenomenon as well as monitoring the state of the detector by means of optical sampling. The method was used to determine the OSL signal loss (fading) characteristics of selected potassium feldspars.

3

Datowanie luminescencyjne. Konstrukcja napromieniacza do weryfikacji efektu mocy dawki

Mandowski Arakdiusz, Mandowska Ewa, Smyka Robert, Majgier Renata, Szufa Katarzyna, Maternicki Krzysztof

Przegląd Elektrotechniczny

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2021

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R. 97, nr 2

24--27

PL

Znając wartość naturalnego tła promieniowania można sposób datować materiały archeologiczne i geologiczne metodami luminescencyjnymi. Szacujemy wiek porównując dawkę naturalną z dawką laboratoryjną. Moce tych dawek różnią się o wiele rzędów wielkości. Nie wiadomo, czy takie porównanie jest uzasadnione. W artykule przedstawiono wyniki teoretyczne i doświadczalne dotyczące efektu mocy dawki oraz koncepcję kontrolowanego elektronicznie napromieniacza do testowania tego efektu.

EN

Knowing the value of the natural radiation background, it is possible to estimate the age of archaeological and geological materials using luminescence methods. We estimate the age by comparing the natural dose with the laboratory one. The dose rates for these two cases doses may fiffer by many orders of magnitude. It is not known whether such a comparison is justified. The article presents theoretical and experimental results concerning the dose rate effect as well as the concept of an electronically controlled irradiator to test this effect.

4

Luminescencyjne datowania w badaniach geoarcheologicznych

Kalicki Tomasz, Głuszewski Wojciech, Frączek Marcin, Przepióra Paweł

Postępy Techniki Jądrowej

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2021

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z. 3

34--41

PL

W artykule omówiono wyniki kilku interdyscyplinarnych geologicznych datowań wykonanych metodami optycznymi. Wiek starszych osadów, głównie plejstoceńskich określono za pomocą termoluminescencji (TL). Młodsze holoceńskie osady datowano z wykorzystaniem optycznie stymulowanej luminescencji (OSL). Na przykładzie osadów mineralnych zawierających kwarc wyjaśniono podstawy obu technik datowania. Często są one stosowane naprzemiennie, w zależności od materiału i jego szacowanego wieku. Metoda OSL rekomendowana jest do badania próbek na stanowiskach archeologicznych. W obu technikach analitycznych mierzy się wielkości dawek pochłoniętych naturalnego promieniowania jonizującego. Zwrócono uwagę na znaczenie laboratoryjnych źródeł promieniowania gamma w wyznaczaniu krzywych kalibracji.

EN

The article discusses the results of several interdisciplinary studies on the dating of geological sediments with optical methods. The age of older sediments, mainly Pleistocene ones, was determined by thermoluminescence (TL). Younger Holocene sediments were dated using optically stimulated luminescence (OSL). The basics of both methods of dating sediments containing quartz are explained. The OSL method is successfully used to determine the age of mineral sediment in archaeological sites. The basis of both analytical techniques is the measurement of the amount of absorbed doses of natural ionizing radiation. Also the importance of laboratory gamma radiation sources used for the determination of calibration curves has been emphasized.

5

Właściwości spektralne i dozymetryczne polikrystalicznego chlorku sodu – naturalnego detektora promieniowania jonizującego

Mandowska Ewa, Biernacka Magdalena, Mandowski Arakdiusz

Przegląd Elektrotechniczny

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2019

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R. 95, nr 9

169--171

PL

Luminescencja długożyciowa jest często wykorzystywana do pomiaru dawki pochłoniętej promieniowania jonizującego. Rolę detektora pełnią odpowiednio przygotowane kryształy dielektryczne. Takim materiałem może być również chlorek sodu (NaCl), który występuje powszechnie w formie soli kuchennej a także naturalnych minerałów (halit). Badania kryształów chemicznie czystego NaCl wykonano metodą optycznie stymulowanej luminescencji oraz spektralnie rozdzielczej termoluminescencji. Wyniki potwierdzają możliwość wykorzystania NaCl w dozymetrii retrospektywnej oraz datowaniu luminescencyjnym.

EN

Long-lived luminescence is often used to measure the dose of absorbed ionizing radiation. The detectors are properly prepared dielectric crystals. This also applies to sodium chloride (NaCl). The material is commonly found in the form of table salt and natural minerals (halite). The article presents the results of radiation-induced luminescence studies in chemically pure sodium chloride crystals. The measurements were performed using optically stimulated luminescence and spectrally resolved thermoluminescence. The results confirm the possibility of using NaCl in retrospective dosimetry and luminescence dating.

6

Czytnik OSL z nieliniową funkcją stymulacji optycznej

Mandowska E., Smyka R., Mandowski A., Kieszkowski R., Majgier R.

Elektronika : konstrukcje, technologie, zastosowania

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2018

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Vol. 59, nr 9

12--15

PL

Optycznie stymulowana luminescencja (OSL) jest jedną z podstawowych metod pomiaru dawki promieniowania jonizującego. Mierzona luminescencja jest proporcjonalna do dawki pochłoniętej przez detektor. Czytniki OSL wykorzystują do stymulacji zazwyczaj światło monochromatyczne o stałej intensywności (CW-OSL) lub zmieniające się liniowo (LM-OSL). Nowy czytnik luminescencyjny Helios X1 oferuje szersze możliwości. Stymulacja detektora może być dokonywana za pomocą dwóch długości fali, które mogą być modulowane nieliniowo niezależnie od siebie. Ten sposób stymulacji umożliwia uzyskanie dodatkowych informacji o właściwościach detektora.

EN

Optically stimulated luminescence (OSL) is one of the basic methods for the measurement of the dose of ionizing radiation. The measured luminescence is proportional to the dose absorbed by the detector. Typically, OSL readers use monochrome light with constant intensity (CW-OSL) or linearly modulated light (LM-OSL) for stimulation. The new Helios X1 luminescence reader offers greater possibilities. The detector stimulation can be performed using two wavelengths that can be independently and non-linearly modulated. This method of stimulation provides additional information relating to detector properties.

7

Wyniki badania OSL izolatorów LSP-24

Sobota R.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 3

24--27

PL

Po raz pierwszy podjęto próbę wykorzystania zjawisk luminescencyjnych OSL do badań izolatorów porcelanowych stosowanych w elektroenergetyce, a dokładniej rzecz ujmując wykorzystano metodę Optycznie Stymulowanej Luminescencji (OSL). Rezultaty tych pomiarów przedstawiono w treści niniejszego artykułu. Omówiono również mechanizm powstawania zjawiska OSL oraz przyjętą metodykę badań, a także scharakteryzowano materiał badawczy czyli porcelanę elektrotechniczną stosowaną do produkcji izolatorów LSP-24.

EN

For the first time luminescence phenomena were used to studies porcelain insulators used in power systems, more precisely Optically Stimulated Luminescence (OSL) method was applied. The results of these measurements are presented in this article. It also discusses the mechanism of OSL phenomenon and the methodology of research as well as research material that is an electrical porcelain which is used in the production process of LSP-24 insulators.

8

An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia

Nartišs M., Kalińska-Nartiša E.

Geologos

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2017

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Vol. 23, No. 1

15--28

EN

In the Middle Gauja Lowland, northeast Latvia, dunes are distributed over a vast glaciolacustrine plain that formed during the retreat of the Fennoscandian ice sheet. Such a direct contact between aeolian and glaciolacustrine sediments can be used to infer depositional settings and decipher to what extent these sediments bear an aeolian component. Our proxies, although preliminary, reveal a limited range of variation in grain-size parameters, a significant presence of quartz grains with silica precipitation and matt-surface grains of various rounding degrees and massive structure combined with horizontal lamination. These are indicative of periglacial-aeolian depositional conditions in the foreland of the Linkuva ice-marginal zone. Sedimentary characteristics do not match a single luminescence date of 9.2±0.6 ka, which significantly postdates the minimum age of the Linkuva ice-marginal zone with 10Be ages between 15.4 and 12.0 ka. Whether deposition started directly after drainage of the Middle Gauja ice-dammed lake or if there is a gap of 2.8–6.2 ka is a matter of debate; only future studies at higher OSL resolution could resolve this.

9

Glinian litu - nowy detektor dozymetryczny

Mandowska E., Mandowski A., Bilski P., Marczewska B., Twardak A., Gieszczyk W.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 9

117-120

PL

Optycznie stymulowana luminescencja (OSL) jest luminescencją emitowaną przez napromieniowany izolator lub półprzewodnik podczas stymulacji światłem o odpowiedniej energii. Intensywność sygnału OSL jest funkcją dawki promieniowania jonizującego, jaka została pochłonięta i dlatego też jest techniką coraz częściej wykorzystywaną w dozymetrii. Wytworzono techniką Micro–Pulling–Down (MPD) nowy detektor OSL glinian litu o dobrej powtarzalności, wysoko czuły na promieniowanie jonizujące oraz wykazujący znacznie lepszą czułość niż komercyjnie stosowany tlenek aluminium. W celu lepszego poznania jego własności lumniescencyjnych przeprowadzono badania termoluminescencji rozdzielczej widmowo.

EN

Optically stimulated luminescence (OSL) is the luminescence emitted from irradiated insulator or semiconductor during stimulation with light of appropriate energy. The OSL intensity is a function of the dose of absorbed ionizing radiation and therefore is a technique increasingly used in dosimetry. New lithium aluminate OSL detector was fabricated using a Micro-Pulling-Down (MPD) technique. The detector has good reproducibility and is highly sensitive to ionizing radiation, having a much better sensitivity than commercially used aluminum oxide detectors. Spectrally resolved thermoluminescence studies were performed to better understand its luminescence properties.

10

Luminescence dating of bricks from the gothic Saint James Church in Toruń

Chruścińska A., Cicha A., Kijek N., Palczewski P., Przegiętka K. R., Sulkowska-Tuszyńska K.

Geochronometria

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2014

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Vol. 41, no. 4

352--360

EN

Saint James Church in Toruń is one of the most important gothic monuments in Poland. The date of the beginning of its construction is known from historical reports but the earlier history of the site remains undiscovered. During the archaeological excavations in years 2010 and 2011 five brick samples were collected for luminescence dating as well as four additional samples from the brick surroundings for the dose rate estimation. The equivalent dose was determined by TL and OSL methods. The TL results differ significantly from the OSL results but the last ones are verified by historical knowledge and radiocarbon dating. Establishing the dose rate from gamma rays needs a special attention because of the complex course of the foundations of the church. The details of the applied approach are presented in the current work. The results obtained indicate that a solid brick construction existed at the site of the presbytery of the Saint James Church before it was build.

11

Estimation of OSL trap parameters by optical “cleaning” — a critical study

Kijek N., Chruścińska A.

Geochronometria

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2014

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Vol. 41, no. 2

160--167

EN

The so-called thermal “cleaning” applied in thermoluminescence analysis allows distinguishing TL signal originating from different traps of comparable thermal depths. Here, the detailed study on the suitability of a similar approach — which can be called optical “cleaning” — for the analysis of OSL process has been carried out by means of computer modelling. The optical “cleaning” is realized by short optical stimulation applied directly after irradiation. It turns out that this approach does not help to separate signals related to various traps having similar optical crosssection (OCS) values. For some sets of trap parameters, sufficiently good reconstruction of the trap optical cross-sections can be achieved by the analysis of the conventional OSL curve obtained directly after sample irradiation, while the OSL curve analysis after “cleaning” does not provide any additional data. For other cases the analysis of both curves with and without “cleaning” leads to optical crosssection values different from those assumed in the model, but just in such situations the optical “cleaning” can be helpful. The differences between the OSL components of the conventional curve and the one obtained after “cleaning” can be used as indicators of an incompatibility of the trap parameters obtained from the OSL analysis with their actual values.

12

Optycznie stymulowana luminescencja detektorów hybrydowych

Mandowska E., Tkaczyk S., Biernacka M., Mandowski A.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 10

112-114

PL

Optycznie stymulowana luminescencja (OSL) jest wykorzystywana do wyznaczania dawki promieniowania jonizującego absorbowanego przez próbkę w trakcie ekscytacji. Najbardziej popularnymi detektorami OSL są kryształy Al2O3:C i BeO. Do pewnych zastosowań ważne jest użycie detektora w postaci dużej, elastycznej folii (np. w medycynie). Opracowano nowe detektory OSL umieszczając mikrokrystality Al2O3:C w organicznej matrycy polimerowej. W artykule prezentujemy wyniki badań nowo syntetyzowanych detektorów hybrydowych.

EN

Optically stimulated luminescence (OSL) may be used for estimating dose of absorbed radiation. The most popular OSL detectors are made of Al2O3:C as well as BeO crystals. For some applications (e.g. in medicine) it would be desirable to construct detectors in the form of higharea flexible foils. New OSL detectors were developed by incorporating Al2O3:C microcrystallites into organic (polymer) matrix. The article presents studies of newly synthesised hybrid detectors.

13

Late Glacial and Holocene vegetation and climate history of an alpine wetland on the Qinghai-Tibetan Plateau

Liu D. L., Chen G., Lai Z., Weis H., Zhou G., Peng M.

Geological Quarterly

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2013

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Vol. 57, No. 2

261-–268

EN

This study provides a vegetation and climate history of an alpine wetland in the centre of China’s Qinghai–Tibetan Plateau (QTP) over the last 14.8 ka. High resolution climate proxies include vegetation (pollen), geochemical (Ba, Rb, δ13C) and physical (particle size and magnetic susceptibility) data; optically stimulated luminescence (OSL) and AMS radiocarbon dating were used to reconstruct the environmental changes in the wetland ecosystem. Based on physical and geochemical proxies, the sucession divided into five stratigraphic units encompassing time intervals of 14.76–14.31, 14.31–13.17, 13.17–4.47, 4.47–0.51 and 0.51–0 ka. The average sedimentation rate of all these units was 0.098 mm/a. The study showed that this ecosystem was sensitive to climate change.

14

An assessment of the luminescence sensitivity of Australian quartz with respect to sediment history

Fitzsimmons K. E.

Geochronometria

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2011

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Vol. 38, no. 3

199-208

EN

This study provides a preliminary systematic characterisation of OSL sensitivity, with re-spect to sediment history, of single grains of Australian quartz from a variety of source rocks and depositional contexts. Samples from two distinct lithologies and with relatively short modern sedi-mentary histories were compared in an examination of the influence of rock type on OSL sensitivity. Sediments derived from weathered sandstone were found to be brighter than those from metamor-phosed schists, suggesting that sensitivity may be inherited from the source rock and its earlier sedi-mentary history. Secondly, quartz from the same source, but different modes of deposition, was com-pared to assess the effect on sensitivity of nature of exposure to light during the most recent bleaching event. Quartz grain sensitivity appears not to vary depending on the mode of sediment deposition, suggesting that the nature of exposure to light during deposition is less important in the sensitisation process. This study highlights the complexity and variety of natural sedimentary quartz, demonstrat-ing the limitations of an investigation based solely on OSL sensitivity. Further systematic investiga-tion into the physical, geological and geomorphological characteristics of sediments is proposed to better understand the mechanisms of luminescence sensitisation in quartz.

15

Luminescence dating of neolithic ceramics from Lumea Nouă, Romania

Benea V., Vanderberghe D., Timar A., Van den Haute P., Cosma C., Gligor M., Florescu C.

Geochronometria

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2007

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Vol. 28

9-16

EN

Luminescence dating was applied to four Neolithic pottery fragments excavated at Lumea Nouă (Alba Iulia, Romania), with the purpose of improving the chronology for the archaeological finds, and hence, the occupational history of the site. The single-aliquot regenerative-dose (SAR) protocol was applied to both blue and infrared stimulated luminescence signals from coarse quartz and polymineral fine grains, respectively. A more conventional approach which uses a multiple-aliquot additive-dose protocol and thermoluminescence signals from polymineral fine grains was applied as well. The characteristics of the OSL and IRSL signals were investigated in terms of behaviour in the SAR protocol, dose response and dose recovery. Additionally, anomalous fading measurements of the 410 nm IRSL emission and of the blue TL emission from polymineral fine-grains were performed. Both signals were observed to be affected by anomalous fading. OSL dating of quartz using the SAR protocol is considered to be the technique of choice; it yields an average age of 6.0±0.4 ka (n = 4), which is in agreement with archaeological expectations. The dating results allow refining the typological interpretation of the objects and improve the chronological framework for the site.

16

Quartz TL decay due to optical bleaching

Chruścińska A., Przegiętka K. R.

Geochronometria

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2005

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Vol. 24

1-6

EN

In spite of many years of research our knowledge of the traps responsible for the OSL in quartz is not complete. Many papers report the complexity of this signal, determine its components and discuss their usefulness for dating procedures. However the experiments carried out so far do not clearly show the source of carriers which recombine on the luminescence centres emitting the OSL. The trap connected with TL peak around 325 C degrees commonly accepted as easily bleachable, can not be the only one responsible for the many observed OSL components. There should exist TL peaks corresponding to these various OSL components, although it is possible that they are related to very deep traps (that is having large energy of thermal ionisation) which are not detected in the conventional TL measurements carried out up to 500 C degrees. With this in mind detailed analysis was made, using sedimentary quartz, of TL curves measured after successively increased time of bleaching performed during the OSL measurement. TL components were determined using fitting procedures and the effect of bleaching on each of these components is demonstrated.