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1

The internal dose rate in quartz grains: experimental data and consequences for luminescence dating

Szymak Agnieszka, Moska Piotr, Poręba Grzegorz, Tudyka Konrad, Adamiec Grzegorz

Geochronometria

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2022

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Vol. 49, no. 1

9--17

EN

This work considers the impact of the internal alpha and beta dose rates in quartz grains obtained from sandy sediments on the results of luminescence dating. The internal dose rates reported here (ca. 0.01–0.21 Gy · ka−1) play a particularly important role, because of low (ca. 0.8–0.9 Gy · ka−1) or very low (ca. 0.4–0.6 Gy · ka−1) external dose rates. In these cases, the internal dose rates form a significant fraction of the total dose rates, often exceeding 10%. Ignoring this contribution would have made the considered luminescence ages artificially older. In our study, we measure both the internal alpha and beta contributions as the latter is usually neglected in the case of quartz. The dose rate measurements were performed using the innovative μDose system.

2

Terapia flash : nowy cud w radioterapii nowotworów złośliwych?

Lenartowicz Aleksandra, Markopolskyi Vasyl, Pracz Janusz

Elektronika : konstrukcje, technologie, zastosowania

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2022

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Vol. 63, Nr 2

27--30

PL

Wydaje się, że nowatorska metoda radioterapii (RT) w leczeniu onkologicznym, z wykorzystaniem promieniowania o wysokiej mocy dawki (FLASH), pozwala znacząco zmniejszyć toksyczność wywołaną promieniowaniem w zdrowych tkankach, jednocześnie wykazując wysoką skuteczność w zabijaniu komórek nowotworowych. Dotychczas przeprowadzono wiele badań przedklinicznych oraz jedno badanie kliniczne, które wykazały korzyści tej metody w porównaniu z metodą konwencjonalną. Dalsze prowadzenie badań napotyka jednak na ograniczony dostęp do urządzeń generujących stabilną i powtarzalną wiązkę promieniowania o ultrawysokiej mocy dawki. Niniejsza praca prezentuje obecny stan wiedzy na temat badań przedklinicznych, hipotez mechanizmu efektu FLASH w komórkach oraz koniecznych udoskonaleń urządzeń generujących wiązkę, tak aby było możliwe osiągnięcie wysokiej mocy dawki przy spełnieniu jednocześnie wymagań terapii.

EN

The novel method of radiation therapy in cancer treatment using high dose radiation (FLASH) appears to be able to significantly reduce radiation-induced toxicity in healthy tissues, while demonstrating high efficiency in killing cancer cells. So far, many preclinical studies and one clinical trial have been carried out, which showed significant advantages of this method compared to the conventional method. However, further research is faced with limited access to devices generating a stable and repeatable beam of ultra-high dose radiation. This paper presents the current state of knowledge on preclinical research, the hypotheses of the FLASH effect mechanism in cells and the necessary improvements to the beam generating devices, so that it is possible to achieve a high dose rate while meeting the requirements of the therapy.

3

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.

4

The impact of the oil and gas industry on NORMs of groundwater and their annual efective dose in Ma’rib, central Yemen

Ali Mohsen M. M., Zhao Hongtao, Li Zhigang, Ahmed O. M. H., Alfasatleh Ibrahim, Maglas Najeeb N. M.

Acta Geophysica

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2020

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Vol. 68, no. 5

1421--1431

EN

The gamma-ray spectrum equipped with a high-purity germanium detector was used to measure the naturally occurring radioactive materials of groundwater samples resources from the petroleum-producing communities of Ma’rib Province-Yemen. Thirty-fve samples were collected from diferent sites. The 40K, 232Th, and 226Ra activity concentrations of groundwater samples for oil and non-oil communities were measured. The annual efective doses due to 40K, 232Th, and 226Ra were calculated and did not show a signifcant health impact. These results can contribute to building a database and provide a general background of the detectable TENORMs for studied areas, which will be useful in any radiological emergency. Signifcantly, the Ma’rib region is rich in oil and gas.

5

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.

6

Natural Radioactivity at the Sin Quyen Iron-Oxide- Copper-Gold Deposit in North Vietnam

Nguyen D. C., Khanh P. L., Jodłowski P., Pieczonka J., Piestrzyński A., Van H. D., Nowak J.

Acta Geophysica

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2016

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Vol. 64, no. 6

2305--2321

EN

The field radiometric and laboratory measurements were performed at the Sin Quyen copper deposit in North Vietnam. The field gamma-ray spectrometry indicated the concentration of uranium ranging from 5.5 to 87 ppm, thorium from 5.6 to 33.2 ppm, and potassium from 0.3 to 4.7%. The measured dose rates ranged from 115 to 582 nGy/h, the highest doses being at the copper ore. Concentrations in the solid samples were in the range of 20-1700 Bq/kg for uranium, 20-92.7 Bq/kg for thorium, and 7-1345 Bq/kg for potassium. The calculated doses were from 22 to 896 nGy/h; both measured and calculated dose rates are mostly related to uranium. Concentrations of radium in water samples were below 0.17 Bq/L. Uranium in water samples was significantly higher than the hydrogeological background; the maximum of 13 Bq/L was at the waste zone pool, but neither radium nor uranium were present in tap water. Radon concentration in the dwelling air was from 42 to 278 Bq/m3 for 222 Rn and from 8 to 193 Bq/m3 for 220Rn. The estimated committed dose rates were principally related to 222Rn concentration and ranged from 1.1 to 8.1 mSv/y.

7

Field gamma spectrometry, Monte Carlo simulations and potential of non-invasive measurements

Guérin G., Mercier N.

Geochronometria

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2012

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Vol. 39, no. 1

40-47

EN

The determination of gamma dose rates is of prior importance in the field of luminescence dating methods. In situ measurements are usually performed by the insertion of dosimeters or a porta-ble gamma spectrometer cell in sediments. In this paper, Monte-Carlo simulations using the GEANT4 toolkit allow the development of a new technique of in-situ gamma dose rate evaluations: a spectrom-eter cell is placed on the surface of sediments under excavation to acquire successive spectra as sedi-ments are removed by excavations. The principle of this non-invasive technique is outlined and its po-tential is discussed, especially in the case of environments in which radioelements are heterogeneous-ly distributed. For such cases, a simple method to reconstruct gamma dose rate values with surface measurements using an attenuator is discussed, and an estimation of errors is given for two simple cases. This technique appears to be applicable, but still needs experimental validation.

8

Evaluation and benchmarking of gamma dose rate employing different nuclear data libraries for MCNP code at the decommissioning stage of Ignalina NPP

Stankunas G., Tonkunas A., Pabarcius R.

Nukleonika

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2011

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Vol. 56, No. 1

71-76

EN

A comparative study was performed to reveal the differences of three nuclear data libraries for gamma dose rate calculations when applied to heterogeneous environment in the case of decommission of the Ignalina Nuclear Power Plant (INPP). The following libraries were investigated by employing the Monte Carlo n-particle transport code (MCNP): ENDF/B-VII, JEFF-3.1 and JENDL-3.3, based on the experiments performed for gamma radiation dose rate measurements inside the emergency core cooling system (ECCS) tank with surface radioactive contamination up to 54 Bq/cm2. MCNP precise simulation and the benchmark between the libraries highlighted the differences of results for the selected case of this investigation. The results revealed that the ENDF library is trustworthy for various dose and shielding calculations and similar applications since it showed a statistically satisfied agreement between the simulation results and experimental data.

9

Clastogenic effects in human lymphocytes exposed to low and high dose rate X-ray irradiation and vitamin C

Konopacka M., Rogoliński J.

Nukleonika

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2011

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Vol. 56, No. 4

253-257

EN

In the present work we investigated the ability of vitamin C to modulate clastogenic effects induced in cultured human lymphocytes by X-irradiation delivered at either high (1 Gy/min) or low dose rate (0.24 Gy/min). Biological effects of the irradiation were estimated by cytokinesis-block micronucleus assay including the analysis of the frequency of micronuclei (MN) and apoptotic cells as well as calculation of nuclear division index (NDI). The numbers of micronucleated binucleate lymphocytes (MNCBL) were 24.85 š 2.67% and 32.56 š 3.17% in cultures exposed to X-rays (2 Gy) delivered at low and high dose rates, respectively. Addition of vitamin C (1-20 mi g/ml) to the medium of cultures irradiated with the low dose rate reduced the frequency of micronucleated lymphocytes with multiple MN in a concentration-dependent manner. Lymphocytes exposed to the high dose rate radiation showed a U-shape response: low concentration of vitamin C significantly reduced the number of MN, whereas high concentration influenced the radiation-induced total number of micronucleated cells insignificantly, although it increased the number of cells with multiple MN. Addition of vitamin C significantly reduced the fraction of apoptotic cells, irrespective of the X-ray dose rate. These results indicate that radiation dose rate is an important exposure factor, not only in terms of biological cell response to irradiation, but also with respect to the modulating effects of antioxidants.

10

Distribution in SAR palaeodoses due to spatial heterogeniety of natural beta dose

Chauhan N., Singhvi A. K.

Geochronometria

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2011

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Vol. 38, no. 3

190-198

EN

In luminescence dating of sediments, Mayya et al. (2006) pointed out that at single grain level, the beta dose for quartz grains is heterogeneous. This heterogeneity arises due the fact that the total potassium in sediment is contributed by few feldspar grains with up to 11-14% stoichiometric potassium (Huntley and Baril, 1997). Beta particles have a range of ~2 mm, which is comparable to grain sizes and inter-grain distances. This fact implies that the spatial fluctuation of beta emitters (K-feldspars) around individual quartz grains results in heterogeneous dose deposition. These fluctua-tions therefore, lead to an inherent spread in palaeodoses received by individual quartz grains. In this study, we compute the spread in single aliquot palaeodoses that arises exclusively due to het-erogeneity in beta radiation dose received by individual grains. We thus postulate that ‘single ali-quots’ (comprising several – typically 100 – heterogeneously irradiated single grains) would have an inherent spread in the palaeodose. In this work, we used Monte Carlo simulations to quantify the ex-tent of spread in palaeodoses arising due to heterogeneity of beta dose and hence put a limit on the precision of age estimation. Simulations results indicated, that, 1) the average of the single aliquot palaeodoses provides the closest approximation to the true palaeodose, 2) the minimum number of al-iquots that are needed to obtain a robust estimate of average palaeodose value depend upon desired precision and the concentration of K, and 3) the ratio of maximum to minimum single aliquot palaeo-dose values for a given K concentration provides a measure of inherent spread arising due to beta dose heterogeneity. Any spread over and above this range, can be ascribed to other sources such as heterogeneous bleaching and sensitivity changes. Radiation dose from other uniformly distributed sources of beta particles (U, Th and Rb) however would reduce this spread.

11

Stability study of free radicals in 10 MeV electron beam irradiated quartz as an EPR dosimetry method

Ziaie F., Mohammadzadeh A., Modarresi M.

Nukleonika

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2009

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Vol. 54, No. 4

251-254

EN

In this work the stability of free radicals induced by a 10 MeV electron beam in quartz samples was studied. The investigations have been done for different doses and different dose rates. For this reason, quartz samples in powder form were irradiated at different dose rates, i.e. 100, 260 and 630 kGy/min for absorbed dose range of similar to 5–80 kGy using the 10 MeV electron beam radiation. The dose values were validated using a polystyrene calorimeter system as a reference standard dosimetry system. The EPR optimum system parameters were defined and EPR responses at room temperature in air were measured and compared. The EPR signal, which is due to the free radicals induced by electron beam, was also investigated at different time intervals to check its stability. The main objective of this work was to study the feasibility of using quartz as a dosimeter. Thus, the variation of EPR signal intensities with the absorbed dose values were evaluated and plotted in a graph. The results show that the variation of dose rate, do not affect considerably the EPR response.

12

Bone powder as EPR dosimetry system for electron and gamma radiation

Ziaie F., Hajiloo N., Fathollahi H., Mehtieva S. I.

Nukleonika

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2009

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Vol. 54, No. 4

267-270

EN

In this work bovine bone powder samples were irradiated at three different dose rates of 100, 260 and 630 kGy/min for the absorbed dose range of 3 to 110 kGy, using 10 MeV electron beam radiation. The samples were subjected to EPR measurement at room temperature in air. The variation of EPR signal intensities were constructed and evaluated base on quantitative data related to the absorbed doses. Moreover, they were compared with the obtained results from the samples irradiated by a 60Co gamma-ray source with a dose rate of 2.65 kGy/h. The time and temperature effects on the EPR response of this dosimeter were also studied. The results indicated that the bone sample was a suitable dosimeter especially for electron beam at high doses.

13

The effects of Holocene podzolisation on radionuclide distributions and dose rates in sandy coastal sediments

Nielsen A. H., Murray A. S.

Geochronometria

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2008

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Vol. 31

53-63

EN

This study analyses the effect of a specific kind of soil development, podzolisation, on selected radionuclide concentrations and the derived dose rates. 100 samples from four sandy, podzolised regions in Jutland, Denmark, were dated by luminescence dating. Dose rates were determined by gamma spectrometry. Of the 100 samples, 31 were retrieved from three profiles intersecting soil horizons affected by podzolisation. At 35 locations, additional material was collected for supplementary geochemical analyses (soil pH, organic carbon content and extractable iron and aluminium). The geochemical data and grain size data were correlated with radionuclide activity concentrations. These correlations do not indicate any significant relationship between organic carbon or extractable iron/aluminium and radionuclide concentrations; this suggests that the radionuclides are mainly internally bound in primary minerals, unlike the extractable iron, which is generally associated with surface coatings. We conclude that the radionuclide distribution in these young sandy soils has been relatively unaffected by the podzolisation process. Thus it appears that the dose rate at these sites is unlikely to have changed significantly with time as a result of podzolisation, because the parent material is relatively unweathered and the activity is dominated by internally bound radionuclides.

14

Overcoming environmental dose rate changes in luminescence dating of waterlain deposits

Li B., Li S-H., Wintle A. G.

Geochronometria

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2008

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Vol. 30

33-40

EN

This study investigates lacustrine and fluvial sediments on the Sala Us River in the Mu Us Desert in central north China. Significant changes in environmental dose rate in part of the section could be shown to have occurred from measurements of the present day radioactivity and by the age reversal for some samples that had been dated by optically stimulated luminescence (OSL) measurements on quartz. These changes in dose rate can be attributed to recent uptake of radioactive elements found in the sediments; this resulted in significant underestimation of the OSL ages. In this study, the new isochron method using K-feldspar grains has been applied to overcome the effects of changes in dose rate. Calculations are used to show that changes in the environmental dose rate factors, i.e. K, U, Th, water content and cosmic ray flux, and disequilibrium in the U and Th decay chains, e.g. radon escape, have a negligible effect on the isochron age. After applying the new isochron method, the effects of changes in dose rate caused by recent uptake of radioactive elements and changes in past water content were effectively overcome and true ages are obtained; this was verified by repeating the luminescence isochron measurements on samples of overlying and underlying sediments.

15

Dose rate effect on LDPE cross-linking induced by electron beam irradiation

Ziaie F., Anvari F., Ghaffari M., Borhani M.

Nukleonika

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2005

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Vol. 50, nr 3

125-127

EN

In this project, the radiation induced cross-linking in low-density polyethylene (LDPE) samples irradiated with the different dose rates of 5 MeV electron beam in the dose range of 20 up to 200 kGy were investigated and compared. The dose rate values were ranged from 13 to 300 kGy/min. The cross-linking of the samples were studied on the basis of gel content measurement and a hot set test. The yield of gel content showed slight increases with decreasing dose rate values. The same results were more clearly observed using the hot set test. It was concluded that, to irradiate the product based on LDPE, any variation in electron beam current causes different dose rates which, in turn, affect the absorbed dose value in materials.

16

A gauge for measuring the dose rate and activity of ophthalmic applicators

Machaj B., Świstowski E., Do H. C., Bilski P., Olko P.

Nukleonika

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2002

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Vol. 47, nr 3

107-111

EN

A gauge was developed for determining the dose rate distribution and surface activity of ophthalmic brachytherapy applicators, particularly for 106Ru applicators. A plastic fi 2×2 mm scintillator is used as the radiation detector, featuring a high pulse count rate, which results in a low 0.5% random error, due to good counting statistics. Automatic gain control of the photomultiplier tube (PMT) is achieved using a LED as the reference light source. The PMT operates in pulse mode. Long term gain variation due to fatigue of the PMT or ambient temperature variation is thus compensated for. The count rate error due to inaccurate setting of the high voltage supply of the PMT is 0.4%, and the instability error over 7 hours of continuous operation does not exceed 1-2%, peak-to-peak.

17

Response of Permanent Monitoring Station (PMS) to increased radioactivity level in comparison with thermoluminescent in comparison with thermoluminescent

Kozak K., Budzanowski M., Gaca P.

Nukleonika

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2001

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Vol. 46, nr 3

101-105

EN

In this work, the response of the Permanent Monitoring Station (PMS) was compared with the readings of environmental thermoluminescent dosimeters (TLD) based on high sensitive MCP-N (LiF:Mg, Cu, P) thermoluminecent detectors and Gamma Tracer, an active device. Thermoluminescent dosimeters were installed close to an automatic warning system of PMS and to a portable Gamma Tracer monitor which is used for long term, continuous measurements in the environment at the INP. For several weeks 137Cs, 60Co, 226Ra and 241Am gamma-ray sources have been placed at distances of a few meters from the dosimeters, in order to modify the radiation environment.