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Title
Abstract
Figures
Introduction
Materials and Methods
Enclosure Material Selection
Resultsdiscussion
Recommendationsconclusions
References
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Environmental Science

An in-situ gamma-ray spectrometer for the deep ocean

Profile image of Christos TsabarisChristos Tsabaris

2018, Applied Radiation and Isotopes

https://doi.org/10.1016/J.APRADISO.2018.08.024
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Abstract

The KATERINA system is upgraded for quantitative measurements at the deep ocean. • MC simulations using MCNP5 reproduced experimental energy spectra and efficiency.

Figures (8)
The specifications of the detection system KATERINA-D. Table 1
The specifications of the detection system KATERINA-D. Table 1
Fig. 1. The total linear attenuation coefficients into the candidate enclosure materials for gamma-rays of 150-2600 keV. The gamma ray attenuation through the enclosure was studied for five candidate materials (acetal, carbon fiber, borosilicate glass, Titanium and stainless steel). The total linear attenuation coefficients for the studied enclosure materials as a function of gamma-ray energy are depicted in Fig. 1. The total linear attenuation coefficients are calculated using the mass attenuation coefficients provided from the XCOM software package (Berger et al., 2010), and the density values of each material. The results showed that acetal is the optimum enclosure material for intermediate water masses (up to 400 m) since it exhibits the lowest linear attenuation coefficient values. The values of bor- osilicate glass to acetal exhibited a ratio from 1.44 (at high energies) to 1.55 (at low energies). The values of carbon fiber to acetal exhibit a
Fig. 1. The total linear attenuation coefficients into the candidate enclosure materials for gamma-rays of 150-2600 keV. The gamma ray attenuation through the enclosure was studied for five candidate materials (acetal, carbon fiber, borosilicate glass, Titanium and stainless steel). The total linear attenuation coefficients for the studied enclosure materials as a function of gamma-ray energy are depicted in Fig. 1. The total linear attenuation coefficients are calculated using the mass attenuation coefficients provided from the XCOM software package (Berger et al., 2010), and the density values of each material. The results showed that acetal is the optimum enclosure material for intermediate water masses (up to 400 m) since it exhibits the lowest linear attenuation coefficient values. The values of bor- osilicate glass to acetal exhibited a ratio from 1.44 (at high energies) to 1.55 (at low energies). The values of carbon fiber to acetal exhibit a
Chemical data for the candidate materials for the detector enclosure. Fig. 2. Simulation configuration of the subsea spectrometer KATERINA-D. Table 2
Chemical data for the candidate materials for the detector enclosure. Fig. 2. Simulation configuration of the subsea spectrometer KATERINA-D. Table 2
Fig. 3. Simulated spectra of KATERINA (solid red line) and KATERINA-D (da- shed line) detection systems, for measurements of *°K in seawater along with the corresponding experimental spectrum of KATERINA acquired in the water tank (solid black line).
Fig. 3. Simulated spectra of KATERINA (solid red line) and KATERINA-D (da- shed line) detection systems, for measurements of *°K in seawater along with the corresponding experimental spectrum of KATERINA acquired in the water tank (solid black line).
Fig. 4. Simulated spectra (1 Bq/L and 7200s measuring period) for the ??*Rn daughters (?"*Pb and 2!*Bi) and ?°°Tl applying the KATERINA-D detection system in seawater. The dashed line represents the 7!*Bi spectrum, the solid line the ?!4Pb spectrum while the dot line the 2°°T] spectrum.
Fig. 4. Simulated spectra (1 Bq/L and 7200s measuring period) for the ??*Rn daughters (?"*Pb and 2!*Bi) and ?°°Tl applying the KATERINA-D detection system in seawater. The dashed line represents the 7!*Bi spectrum, the solid line the ?!4Pb spectrum while the dot line the 2°°T] spectrum.
Fig. 5. The detection efficiency values for different enclosure materials. The experimental value of 40K in the field is also included (diamond).
Fig. 5. The detection efficiency values for different enclosure materials. The experimental value of 40K in the field is also included (diamond).
Fig. 6. The experimental spectrum acquired at 2700 m for a period of 7200s, the corresponding simulated spectrum for *°K (solid line) and the theoretical fitted spectrum (solid red line) using a linear combination of the simulated spectra for *°K, 2!*Pb, 2!4Bi and ?°°Tl. The simulated *°K spectrum was nor- malized to the measurement period (7200s) and to the experimental activity concentration (13.4 Bq/L), while the simulated spectra for radon progenies (7"4pb, ?!4Bi) and ?°°T] were normalized to the measurement period (7200s). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
Fig. 6. The experimental spectrum acquired at 2700 m for a period of 7200s, the corresponding simulated spectrum for *°K (solid line) and the theoretical fitted spectrum (solid red line) using a linear combination of the simulated spectra for *°K, 2!*Pb, 2!4Bi and ?°°Tl. The simulated *°K spectrum was nor- malized to the measurement period (7200s) and to the experimental activity concentration (13.4 Bq/L), while the simulated spectra for radon progenies (7"4pb, ?!4Bi) and ?°°T] were normalized to the measurement period (7200s). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)
References The research leading to these results has received part of the funding from the LEVECO programme under the frame of Programming Agreements between Research Centers and GSRT/IKY/SIEMENS (2014-2016). Dr. E. G. Androulakaki would like to acknowledge IKY, as part of this research is implemented through IKY scholarships pro- gramme and co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the action entitled “Reinforcement of Postdoctoral Researchers”, in the framework of the Operational Programme”Human Resources Development Program, Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) 2014 — 2020. All authors would also like to ac- knowledge P. Renieris and the crew of the research vessel AEGEAO for supporting detector battery installation to the Rosetta and system de- ployment.
References The research leading to these results has received part of the funding from the LEVECO programme under the frame of Programming Agreements between Research Centers and GSRT/IKY/SIEMENS (2014-2016). Dr. E. G. Androulakaki would like to acknowledge IKY, as part of this research is implemented through IKY scholarships pro- gramme and co-financed by the European Union (European Social Fund - ESF) and Greek national funds through the action entitled “Reinforcement of Postdoctoral Researchers”, in the framework of the Operational Programme”Human Resources Development Program, Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) 2014 — 2020. All authors would also like to ac- knowledge P. Renieris and the crew of the research vessel AEGEAO for supporting detector battery installation to the Rosetta and system de- ployment.

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References (44)

  1. Aakenes, U.R., 1995. Radioactivity monitored from moored oceanographic buoys. Chem. Ecol. 10, 61-69.
  2. Androulakaki, E.G., Tsabaris, C., Eleftheriou, G., Kokkoris, M., Patiris, D.L., Pappa, F.K., Vlastou, R., 2016a. Efficiency calibration for in situ γ-ray measurements on the seabed using Monte Carlo simulations: application in two different marine environ- ments. J. Environ. Radioact. 164, 47-59.
  3. Androulakaki, E.G., Kokkoris, M., Tsabaris, C., Eleftheriou, G., Patiris, D.L., Pappa, F.K., Vlastou, R., 2016b. In situ γ-ray spectrometry in the marine environment using full spectrum analysis for natural radionuclides. Appl. Radiat. Isot. 114, 76-86.
  4. Androulakaki, E.G., Tsabaris, C., Eleftheriou, G., Kokkoris, M., Patiris, D.L., Vlastou, R., 2015. Seabed radioactivity based on in situ measurements and Monte Carlo simula- tions. Appl. Radiat. Isot. 101, 83-92.
  5. Bagatelas, C., Tsabaris, C., Kokkoris, M., Papadopoulos, C.T., Vlastou, R., 2010. Determination of marine gamma activity and study of the minimum detectable ac- tivity (MDA) in 4pi geometry based on Monte Carlo simulation. Environ. Monit. Assess. 165, 159-168.
  6. Bellou, N., Papathanassiou, E., Dobretsov, S., Lykousis, V., Colijn, F., 2012. The effect of substratum type, orientation and depth on the development of bacterial deep-sea biofilm communities grown on artificial substrata deployed in the Eastern Mediterranean. Biofouling 28, 199-213.
  7. Berger M.J., Hubbell J.H., Seltzer S.M., Chang J., Coursey J.S., Sukumar R., Zucker D.S., Olsen K., 2010. XCOM: photon cross section database (version 1.5). Online available: 〈http://physics.nist.gov/xcom〉.
  8. Berlizov, A.N., 2006. MCNP-CP a correlated particle radiation source extension of a general purpose Monte Carlo N particle transport code. In: Semkov, T.M., Pommé, S., Jerome, S.M. (Eds.), ACS Symposium Series 945. American Chemical Society, Washington DC, pp. 183-194.
  9. Caffrey, J.A., Higley, K.A., Farsoni, A.T., Smith, S., Menn, S., 2012. Development and deployment of an underway radioactive cesium monitor off the Japanese coast near Fukushima Dai-ichi. J. Environ. Radioact. 111, 120-125.
  10. Dymond, J., Cobler, R., Gordon, L., Biscaye, P., Mathieu, G., 1983. 226 Ra and 222 Rn contents of galapagos rift hydrothermal waters -the importance of low-temperature interactions with crustal rocks. Earth Planet. Sci. Lett. 64, 417-429.
  11. Gwynn, J.P., Nikitin, A., Shershakov, V., Heldal, H.-E., Lind, B., Teien, H.-C., Lind, O.-C., Sidhu, R.-S., Bakke, G., Kazennov, A., Grishin, D., Fedorova, A., Blinova, O., Svaeren, I., Liebig, P.-L., Salbu, B., Wendell, C.-C., Strålberg, E., Valetova, N., Petrenko, G., Katrich, I., Logoyda, I., Osvath, I., Levy, I., Bartocci, J., Pham, M., Sam, A., Nies, H., Rudjord, A.-L., 2016. Main results of the 2012 joint Norwegian -Russian expedition to the dumping sites of the nuclear submarine K-27 and solid radioactive waste in Stepovogo Fjord, Novaya Zemlya. J. Environ. Radioact. 151, 417-426.
  12. Li, Hongzhi, Wang, Lei, Zhang, Jinzhao, Li, Chunfang, 2016. Research on and Application of Deep-sea Environmental Radioactivity Online Monitoring Technology. IEEE 978-1- 4673-9724.
  13. Kalfas, C.A., Axiotis, M., Tsabaris, C., 2016. SPECTRW: a software package for nuclear and atomic spectroscopy. Nucl. Instrum. Methods Phys. Res. Sect. A: Accel. Spectrometers, Detect. Assoc. Equip. 830, 265-274.
  14. Kofuji, H., 2015. In situ measurement of 134Cs and 137Cs in seabed using underwater c- spectrometry systems: application in surveys following the Fukushima Dai-ichi Nuclear Power Plant accident. J. Radioanal. Nucl. Chem. 303, 1575-1579.
  15. Maučec, M., de Meijer, R.J., Rigollet, C., Hendricks, P.H.G.M., Jones, D.G., 2004. Detection of radioactive particles offshore by γ-ray spectrometry Part I: monte Carlo assessment of detection of depth limits. Nucl. Instrum. Methods Phys. Res. A 525, 593-609.
  16. De Meijer, R.J., Stapel, C., Jones, D.G., Roberts, P.D., Rozendaal, A., Macdonald, W.G., et al., 1997. Improved and new uses of natural radioactivity in mineral exploration and processing. Explor. Min. Geol. 6, 105-117.
  17. NESTOR Institute for Deep Sea Research, 2015. Private communication with Pressure Test Lab.
  18. Osvath, I., Povinec, P.P., 2001. Seabed γ-ray spectrometry applications at IAEA-MEL. J. Environ. Radioact. 53, 335-349.
  19. Osvath, I., Povinec, P.P., Livingston, H.D., Ryan, T.P., Muslow, S., Commanducci, J.-F., 2005. Monitoring of radioactivity in NW Irish Sea water using a stationary under- water gamma-ray spectrometer with satellite data transmission. J. Radioanal. Nucl. Chem. 263, 437-440.
  20. Pelowitz, D.B., 2011. MCNPX Users Manual, Version 2.7.0. Los Alamos National Laboratory, pp. 1-645 (Report LA-CP-11-00438).
  21. Petrinec, B., Franić, Z., Leder, N., Tsabaris, C., Bituh, T., Marović, G., 2010. Gamma ra- diation and dose rate investigations on the Adriatic islands of magmatic origin. Radiat. Prot. Dosim. 139, 551-559.
  22. Povinec, P.P., Osvath, I., Baxter, M.S., 1996. Underwater gamma-spectrometry with HpGe and NaI(Tl) Detectors. Appl. Radiat. Isot. 47, 1127-1133.
  23. Povinec, P.P., Osvath, I., Baxter, M.S., Ballestra, S., Carrol, J., Gastaud, J., Harms, I., Huynh-Ngoc, L., Liong, Kwong, L.L.W., Pettersson, H., 1997. Summary of IAEA-MEL's investigation of Kara Sea radioactivity and radiological assessment. Mar. Pollut. Bull. 35, 235-241.
  24. Povinec, P.P., Woodhead, D., Blowers, P., Bonfield, R., Cooper, M., Chen, Q., Dahlgaard, H., Dovlete, C., Fox, V., Froehlich, K., Gastaud, J., Gröning, M., Hamilto, T., Ikeuchi, Y., Kanisch, G., Krüger, A., Kwong, L.L.W., Matthews, M., Morgenstern, U., Mulsow, S., Pettersson, H., Smedley, P., Taylor, B., Taylor, C., Tinker, R., 1999. Marine radioactivity assessment of Mururoa and Fangataufa atolls. Sci. Total Environ. 237-238 249-267.
  25. Povinec, P.P., La Rosa, J., Lee, S.-H., Mulsow, S., Osvath, I., Wyse, E., 2001. Recent de- velopments in radiometric and mass spectrometry methods for marine radioactivity measurements. J. Radioanal. Nucl. Chem. 248, 713-718.
  26. Povinec, P., Aggarwal, P., Aureli, A., Burnett, W.C., Kontar, E.A., Kulkarni, K.M., Moore, W.S., Rajar, R., Taniguchi, M., Comanducci, J.-F., Cusimano, G., Dulaiova, H., Gatto, L., Hauser, S., Levy-Palomo, I., Ozorovich, Y.R., Privitera, A.M.G., Schiavo, M.A., 2006a. Characterisation of submarine ground water discharge offshore south-eastern Sicily -SGD collaboration. J. Environ. Radioact. 89, 81-101.
  27. Povinec, P.P., Comanducci, J.-F., Levy-Palomo, I., Oregioni, B., 2006b. Monitoring of submarine groundwater discharge along the Donnalucata coast in the south-eastern Sicily using underwater gamma-ray spectrometry. Cont. Shelf Res. 26, 874-884.
  28. Povinec, P.P., Bokuniewicz, H., Burnett, W.C., Cable, J., Charette, M., Comanducci, J.-F., Kontar, E.A., Moore, W.S., Oberdorfer, J.A., de Oliveira, J., Peterson, R., Stieglitz, T., Taniguchi, M., 2008. Isotope tracing of submarine groundwater discharge offshore Ubatuba, Brazil: results of the IAEA-UNESCO SGD project. J. Environ. Radioact. 99, 1596-1610.
  29. van Put, P., Debauche, A., De Lellis, C., Adam, V., 2004. Performance level of an au- tonomous system of continuous monitoring of radioactivity in seawater. J. Environ. Radioact. 72, 177-186.
  30. Sartini, L., Simeone, F., Pani, P., Lo Bue, N., Marinaro, G., Grubich, A., Lobko, A., Etiope, G., Capone, A., Favali, P., Gasparoni, F., Bruni, F., 2011. GEMS: underwater spec- trometer for long-term radioactivity measurements. Nucl. Instrum. Methods Phys. Sect. A: Accel. Spectrom. Detect. Assoc. Equip. 626-627 (S145-S147).
  31. Soukissian, T.H., Chronis, G.T., Nittis, K., 1999. POSEIDON: operational marine mon- itoring system for greek seas. Sea Technol. 40, 31-37.
  32. Thornton, B., Ohnishi, S., Ura, T., Odano, N., Fujita, T., 2013. Continuous measurement of radionuclide distribution off Fukushima using a towed sea-bed gamma-ray spectro- meter. Deep-Sea Res. 79, 10-19.
  33. Tsabaris, C., Thanos, I., 2004. An underwater sensing system for monitoring radioactivity in the marine environment. Mediterr. Mar. Sci. 5, 5-17.
  34. Tsabaris, C., Ballas, D., 2005. On line gamma-ray spectrometry at open sea. Appl. Radiat. Isot. 62, 83-89.
  35. Tsabaris, C., Bagatelas, C., Dakladas, Th, Papadopoulos, C.T., Vlastou, R., Chronis, G.T., 2008. An autonomous in situ detection system for radioactivity measurements in the marine environment. Appl. Radiat. Isot. 66, 1419-1426.
  36. Tsabaris, C., Scholten, J., Karageorgis, A.P., Comanducci, J.-F., Georgopoulos, D., Wee Kwong, L.L., Patiris, D.L., Papathanassiou, E., 2010. Underwater in situ measure- ments of radionuclides in selected submarine groundwater springs, Mediterranean Sea. Radiat. Prot. Dosim. 142, 273-281.
  37. Tsabaris, C., Patiris, D.L., Karageorgis, A.P., Eleftheriou, G., Papadopoulos, V.P., Georgopoulos, D., Papathanassiou, E., Povinec, P.P., 2012. In-situ radionuclide characterization of a submarine groundwater discharge site at Kalogria Bay, Stoupa, Greece. J. Environ. Radioact. 108, 50-59.
  38. Tsabaris, C., Zervakis, V., Kaberi, H., Delfanti, R., Georgopoulos, D., Lampropoulou, M., Kalfas, C.A., 2015. 137 Cs vertical distribution at the deep basins of the North and Central Aegean Sea, Greece. J. Environ. Radioact. 132, 47-56.
  39. Tsabaris, C., Prospathopoulos, A., 2011. Automated quantitative analysis of in-situ NaI measured spectra in the marine environment using a wavelet-based smoothing technique. Appl. Radiat. Isot. 69 (10), 1546-1553.
  40. Vlachos, D.S., Tsabaris, C., 2005. Response function calculation of an underwater gamma ray NaI(Tl) spectrometer. Nucl. Instrum. Methods Phys. Res. A 539, 414-420.
  41. Vlastou, R., Ntziou, I.Th, Kokkoris, M., Papadopoulos, C.T., Tsabaris, C., 2006. Monte Carlo simulation of γ-ray spectra from natural radionuclides recorded by a NaI detector in the marine environment. Appl. Radiat. Isot. 64, 116-123.
  42. Wedekind, Ch, Schilling, G., Grüttmüller, M., Becker, K., 1999. Gamma-radiation mon- itoring network at sea. Appl. Radiat. Isot. 50, 733-741.
  43. Zhang, Y., Li, C., Liu, D., Zhang, Y., Liu, Y., 2015. Monte Carlo simulation of a NaI(Tl) detector for in situ radioactivity measurements in the marine environment. Appl. Radiat. Isot. 98, 44-48.
  44. X-5 Monte Carlo Team, 2003. MCNP5 -A General Monte Carlo N-Particle Transport Code, Version 5. Los Alamos National Laboratory (LA-UR-03-198, LA-CP-03-0245).

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Georgios Eleftheriou

HNPS Proceedings

A new medium resolution (based on a 2″x2″CeBr3 crystal) gamma-ray spectrometer named “GeoMAREA” was developed and applied for measuring radioactivity in aquatic environments. The system is capable for qualitative and quantitative measurement of radionuclides in aquatic environments with maximum depth of deployment up to 600 m. A special software is developed to fulfill different demands of the end-users in order to: a) provide real time data using the cable mode, b) perform communication tasks with a data center transferring (near) real time data, c) provide time series in sequential buffers for continuous monitoring in a stand-alone mode and d) provide profile data and subsequently maps using mobile vehicles (underway mode). The spectrometer was calibrated first using point sources for energy, energy resolution and efficiency. The system offers activity concentrations of all detected gamma-ray emitters in Bq/m3 using the marine efficiency calibration, which is reproduced via the MC...

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In situ gamma-ray measurements of marine sediment using Monte Carlo simulation
C. Tsabaris

HNPS Proceedings, 2012

This work outlines the progress in developing a new method for in situ radioactivity measurements of marine sediments. The method combines the underwater gamma-ray spectrometer (a system named KATERINA based on a NaI(Tl) detector) with Monte-Carlo calculations using the MCNP5 code. This method aims at allowing for an accurate quantitative determination of activity concentrations in marine sediments (using the in situ system), which can be applied in different areas and for variable sediment structures.As a first step, the MCNP5 code has been successfully applied for the standard 4π geometry in the aquatic environment, reproducing results of the marine efficiency as previously deduced by the GEANT4 code. The experimental set up geometry was introduced in MCNP5 using detailed information for the geometry and the materials. Moreover, a first simulated estimation of the in situ efficiency for sediment measurements is presented for 40K (1460.8 keV). For this purpose a new model was const...

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Environmental Gamma-Ray Observation in Deep Sea
Hidenori Kumagai

2012

Vehicles (ROVs). In addition, an on-line real-time environmental gamma ray observatory has operated at deep seafloor of 1174m water depth for more than ten-years at Hatsushima Observatory, Sagami-Bay, southern coast of mainland Japan. All the deep-sea systems developed are based on an on-land system originally developed at RIKEN (the Institute of Physical and Chemical Research; Okano et al., 1980; Kumagai and Okano, 1982). Since 1984, Deep-Sea Research department of JAMSTEC had developed deepsea gamma ray sensor available down to 6500m of water depth (Hattori et al., 1997; 2000; 2002). To achieve required sensitivity for the system, NaI(Tl) scintillation counter has applied to the measurement that stored into Al-pressure vessel (Plate 1). Figure 1 is a schematic block diagram of the system. During the development, various assemblages of high voltage supply, data transfer, and sizes or shapes of scintillator were tried; three or two inches spherical, or three inches cylindrical scintillators. As the current model, three inches

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On line gamma-ray spectrometry at open sea
Christos Tsabaris

Applied Radiation and Isotopes, 2005

Set up and application of a stationary monitoring network for measuring specific gactivities in the Aegean Sea are described. Three NaI scintillator based spectrometers have been used to detect the gamma rays. The gross counting rate of each system was found to be nearly constant, when there was no rainfall. The volumetric activity of the natural gamma-ray emitter 40 K in open sea varied from 12,200 to 13,000 Bq/m 3 . The counting rate for 1461 keV 40 K radiation was measured by intercalibration with an appropriate salinity sensor mounted close to the NaI-detector system. A simple relation between the counting rate and the salt concentration has been observed. The amount of the artificial radioactivity from 137 Cs was increased up to seven times higher after strong rainfall, compared to the radiation level as given in literature (3.5-5.5 Bq/m 3 ), while the 214 Bi counting rate was increased up to ten times compared to the data without rainfall.

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GEMS: Underwater spectrometer for long-term radioactivity measurements
Francesco Gasparoni

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2011

a b s t r a c t GEMS (Gamma Energy Marine Spectrometer) is a prototype of an autonomous radioactivity sensor for underwater measurements, developed in the framework for a development of a submarine telescope for neutrino detection (KM3NeT Design Study Project). The spectrometer is highly sensitive to gamma rays produced by 40 K decays but it can detect other natural (e.g., 238 U, 232 Th) and anthropogenic radionuclides (e.g., 137 Cs). GEMS was firstly tested and calibrated in the laboratory using known sources and it was successfully deployed for a long-term (6 months) monitoring at a depth of 3200 m in the Ionian Sea (Capo Passero, offshore Eastern Sicily). The instrument recorded data for the whole deployment period within the expected specifications. This monitoring provided, for the first time, a continuous time-series of radioactivity in deep-sea.

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  • Environmental Science
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    Rainfall Investigation by Means of Marine In Situ Gamma-ray Spectrometry in Ligurian Sea, Mediterranean Sea, Italy
    Christos Tsabaris

    Journal of Marine Science and Engineering

    Marine in situ gamma-ray spectrometry was utilized for a rainfall study at the W1M3A observing system in Ligurian Sea, Mediterranean Sea, Italy. From 7 June to 10 October 2016, underwater total gamma-ray counting rate (TCR) and the activity concentration of radon daughters 214Pb, 214Bi and potassium 40K were continuously monitored along with ambient noise and meteorological parameters. TCR was proven as a good rainfall indicator as radon daughters’ fallout resulted in increased levels of marine radioactivity during and 2–3 h after the rainfall events. Cloud origin significantly affects TCR and radon progenies variations, as aerial mass trajectories, which extend upon terrestrial areas, result in higher increments. TCR and radon progenies concentrations revealed an increasing non-linear trend with rainfall height and intensity. 40K was proven to be an additional radio-tracer as its dilution was associated with rainfall height. 40K variations combined with 214Bi measurements can be us...

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