Matteo Albéri | Università degli Studi di Ferrara (original) (raw)

Papers by Matteo Albéri

Advances in Water Resources, 2019

The global warming effects put in danger global water availability and make necessary todecrease ... more The global warming effects put in danger global water availability and make necessary todecrease water wastage, e.g., by monitoring global irrigation. Despite this, global irrigation information is scarce due to the absence of a solid estimation technique. In this study, we applied an innovative approach to retrieve irrigation water from high spatial and temporal resolution Soil Moisture (SM) data obtained from an advanced sensor based on Proximal Gamma-Ray (PGR) spectroscopy, in a field located in Emilia Romagna (Italy). The results show that SM is a key variable to obtain information about the amount of water applied to plants, with Pearson correlation between observed and estimated daily irrigation data ranges from 0.88 to 0.91 by using different calibration methodology. With the aim of reproducing the working conditions of satellites measuring soil moisture, we sub-sampled SM hourly time series at larger time steps. The results demonstrated that the methodology is still capable to perform the daily (weekly) irrigation estimation with Pearson Correlation around 0.6 (0.7) if the time step is not greater than 36 (48) hours.

Aims. We present the performance of the Integral Field Spectrograph (IFS) of SPHERE, the high-con... more Aims. We present the performance of the Integral Field Spectrograph (IFS) of SPHERE, the high-contrast imager for the ESO
VLT telescope designed to perform imaging and spectroscopy of extrasolar planets, obtained from tests performed at the Institut
de Planétologie et d’Astrophysique de Grenoble facility during the integration phase of the instrument.
Methods. The tests were performed using the instrument software purposely prepared for SPHERE. The output data were reduced
applying the SPHERE data reduction and handling software, adding an improved spectral deconvolution procedure. To this aim, we
prepared an alternative procedure for the spectral subtraction exploiting the principal component analysis algorithm. Moreover, a
simulated angular differential imaging procedure was also implemented to estimate how the instrument performed once this procedure
was applied at telescope. The capability of the IFS to faithfully retrieve the spectra of the detected faint companions was also
considered.
Results. We found that the application of the updated version of the spectral deconvolution procedure alone, when the algorithm
throughput is properly taken into account, gives us a 5σ limiting contrast of the order of 5 × 10−6 or slightly better. The further application
of the angular differential imaging procedure on these data should allow us to improve the contrast by one order of magnitude
down to around 7×10−7 at a separation of 0.3 arcsec. The application of a principal component analysis procedure that simultaneously
uses spectral and angular data gives comparable results. Finally, we found that the reproducibility of the spectra of the detected faint
companions is greatly improved when angular differential imaging is applied in addition to the spectral deconvolution.

Journal of Radioanalytical and Nuclear Chemistry, 2015

The feasibility of using certified reference materials for the full energy efficiency calibration... more The feasibility of using certified reference materials for the full energy efficiency calibration of p-type coaxial high-purity germanium detectors for the determination of radioactivity in environmental samples is discussed. The main sources of uncertainty are studied and the contributions to the total uncertainty budget for the most intense gamma lines are presented. The correction factors due to self-absorption and true coincidence summing effects are discussed in detail. The calibration procedure is validated for natural and artificial radionuclide determination in different matrices through an internal cross-validation and through the participation in a world-wide open proficiency test.

Geoderma, 2019

Proximal gamma-ray spectroscopy supported by adequate calibration and correction for growing biom... more Proximal gamma-ray spectroscopy supported by adequate calibration and correction for growing biomass is an effective field scale technique for a continuous monitoring of top soil water content dynamics to be potentially employed as a decision support tool for automatic irrigation scheduling. This study demonstrates that this approach has the potential to be one of the best space–time trade-off methods, representing a joining link between punctual and satellite fields of view. The inverse proportionality between soil moisture and gamma signal is theoretically derived taking into account a non-constant correction due to the presence of growing vegetation beneath the detector position. The gamma signal attenuation due to biomass is modelled with a Monte Carlo-based approach in terms of an equivalent water layer which thickness varies in time as the crop evolves during its life-cycle. The reliability and effectiveness of this approach is proved through a 7 months continuous acquisition of terrestrial gamma radiation in a 0.4 ha tomato (Solanum lycopersicum) test field. We demonstrate that a permanent gamma station installed at an agricultural field can reliably probe the water content of the top soil only if systematic effects due to the biomass shielding are properly accounted for. Biomass corrected experimental values of soil water content inferred from radiometric measurements are compared with gravimetric data acquired under different soil moisture levels, resulting in an average percentage relative discrepancy of about 3\% in bare soil condition and of 4\% during the vegetated period. The temporal evolution of corrected soil water content values exhibits a dynamic range coherent with the soil hydraulic properties in terms of wilting point, field capacity and saturation.

IEEE Transactions on Geoscience and Remote Sensing, 2018

In this paper, we present the results of an 5-h airborne gamma-ray survey carried out over the Ty... more In this paper, we present the results of an 5-h airborne gamma-ray survey carried out over the Tyrrhenian Sea in which the height range (77-3066) m has been investigated. Gamma-ray spectroscopy measurements have been performed using the AGRS\_16L detector, a module of four 4L NaI(Tl) crystals. The experimental setup was mounted on the Radgyro, a prototype aircraft designed for multisensorial acquisitions in the field of proximal remote sensing. By acquiring high-statistics spectra over the sea (i.e., in the absence of signals having geological origin) and by spanning a wide spectrum of altitudes, it has been possible to split the measured count rate into a constant aircraft component and a cosmic component exponentially increasing with increasing height. The monitoring of the count rate having pure cosmic origin in the >3-MeV energy region allowed to infer the background count rates in the40K,214Bi, and208Tl photopeaks, which need to be subtracted in processing airborne gamma-ray data in order to estimate the potassium, uranium, and thorium abundances in the ground. Moreover, a calibration procedure has been carried out by implementing the CARI-6P and Excel-based program for calculating atmospheric cosmic ray spectrum dosimetry tools, according to which the annual cosmic effective dose to human population has been linearly related to the measured cosmic count rates.

Atmospheric Environment, 2017

222Rn is a noble radioactive gas produced along the 238U decay chain, which is present in the maj... more 222Rn is a noble radioactive gas produced along the 238U decay chain, which is present in the majority of soils and rocks. As 222Rn is the most relevant source of natural background radiation, understanding its distribution in the environment is of great concern for investigating the health impacts of low-level radioactivity and for supporting regulation of human exposure to ionizing radiation in modern society. At the same time, 222Rn is a widespread atmospheric tracer whose spatial distribution is generally used as a proxy for climate and pollution studies. Airborne gamma-ray spectroscopy (AGRS) always treated 222Rn as a source of background since it affects the indirect estimate of equivalent 238U concentration. In this work the AGRS method is used for the first time for quantifying the presence of 222Rn in the atmosphere and assessing its vertical profile. High statistics radiometric data acquired during an offshore survey are fitted as a superposition of a constant component due to the experimental setup background radioactivity plus a height dependent contribution due to cosmic radiation and atmospheric 222Rn. The refined statistical analysis provides not only a conclusive evidence of AGRS 222Rn detection but also a (0.96 ± 0.07) Bq/m3 222Rn concentration and a (1318 ± 22) m atmospheric layer depth fully compatible with literature data.

Journal of Maps, 2015

We present a detailed map of uranium distribution and its uncertainties in the Variscan Basement ... more We present a detailed map of uranium distribution and its uncertainties in the Variscan Basement of Northeastern Sardinia (VBNS) at a scale of 1:100,000. An area of 2100 km2 was investigated by means of 535 data points obtained from laboratory and in situ gamma-ray spectrometry measurements. These data volume corresponds to the highest sampling density of the European Variscides, aimed at studying the genetic processes of the upper crust potentially triggered by an enrichment of radiogenic heat-producing elements. For the first time, the Kriging with Variance of Measurement Error method was used to assign weights to the input data which are based on the degree of confidence associated with the measurements obtained using different gamma-ray spectrometry techniques. A detailed tuning of the model parameters for the adopted Experimental Semi-Variogram led to the identification of a maximum distance of spatial variability coherent to the observed tendency of the experimental data. We demonstrate that the obtained uranium distribution in the VBNS, characterized by several calc-alkaline plutons emplaced within migmatitic massifs and amphibolite-facies metamorphic rocks, is an excellent benchmark for the study of ‘hot’ collisional chains. The uranium map of VBNS, and in particular the Arzachena minor pluton, confirms the emplacement model based on the recognition of the different petrological associations characterizing the Variscan magmatic processes in the Late Paleozoic. Furthermore, the presented model of the uranium content of the geological bedrock is a potential baseline for future mapping of radon-prone areas.

Education Science, 2019

Although environmental radioactivity is all around us, the collective public imagination often as... more Although environmental radioactivity is all around us, the collective public imagination often associates a negative feeling to this natural phenomenon. To increase the familiarity with this phenomenon we have designed, implemented, and tested an interdisciplinary educational activity for pre-collegiate students in which nuclear engineering and computer science are ancillary to the comprehension of basic physics concepts. Teaching and training experiences are performed by using a 4" × 4" NaI(Tl) detector for in-situ and laboratory γ-ray spectroscopy measurements. Students are asked to directly assemble the experimental setup and to manage the data-taking with a dedicated Android app, which exploits a client-server system that is based on the Bluetooth communication protocol. The acquired γ-ray spectra and the experimental results are analyzed using a multiple-platform software environment and they are finally shared on an open access Web-GIS service. These all-round activities combining theoretical background, hands-on setup operations, data analysis, and critical synthesis of the results were demonstrated to be effective in increasing students' awareness in quantitatively investigating environmental radioactivity. Supporting information to the basic physics concepts provided in this article can be found at http://www.fe.infn.it/radioactivity/ educational. a mixed method that is based on applying nuclear engineering concepts and computer science tools to explore in-situ environmental radioactivity.

Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial ... more Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial radionuclides measured during airborne surveys. The frontiers of radiometric measurements with UAV require light and accurate altimeters flying at some 10 m from the ground. We equipped an aircraft with seven altimetric sensors (three low-cost GNSS receivers, one inertial measurement unit, one radar altimeter and two barometers) and analyzed ~3 h of data collected over the sea in the (35–2194) m altitude range. At low altitudes (H < 70 m) radar and barometric altimeters provide the best performances, while GNSS data are used only for barometer calibration as they are affected by a large noise due to the multipath from the sea. The ~1 m median standard deviation at 50 m altitude affects the estimation of the ground radioisotope abundances with an uncertainty less than 1.3%. The GNSS double-difference post-processing enhanced significantly the data quality for H > 80 m in terms of both altitude median standard deviation and agreement between the reconstructed and measured GPS antennas distances. Flying at 100 m the estimated uncertainty on the ground total activity due to the uncertainty on the flight height is of the order of 2%.

Advances in Water Resources, 2019

The global warming effects put in danger global water availability and make necessary todecrease ... more The global warming effects put in danger global water availability and make necessary todecrease water wastage, e.g., by monitoring global irrigation. Despite this, global irrigation information is scarce due to the absence of a solid estimation technique. In this study, we applied an innovative approach to retrieve irrigation water from high spatial and temporal resolution Soil Moisture (SM) data obtained from an advanced sensor based on Proximal Gamma-Ray (PGR) spectroscopy, in a field located in Emilia Romagna (Italy). The results show that SM is a key variable to obtain information about the amount of water applied to plants, with Pearson correlation between observed and estimated daily irrigation data ranges from 0.88 to 0.91 by using different calibration methodology. With the aim of reproducing the working conditions of satellites measuring soil moisture, we sub-sampled SM hourly time series at larger time steps. The results demonstrated that the methodology is still capable to perform the daily (weekly) irrigation estimation with Pearson Correlation around 0.6 (0.7) if the time step is not greater than 36 (48) hours.

Aims. We present the performance of the Integral Field Spectrograph (IFS) of SPHERE, the high-con... more Aims. We present the performance of the Integral Field Spectrograph (IFS) of SPHERE, the high-contrast imager for the ESO
VLT telescope designed to perform imaging and spectroscopy of extrasolar planets, obtained from tests performed at the Institut
de Planétologie et d’Astrophysique de Grenoble facility during the integration phase of the instrument.
Methods. The tests were performed using the instrument software purposely prepared for SPHERE. The output data were reduced
applying the SPHERE data reduction and handling software, adding an improved spectral deconvolution procedure. To this aim, we
prepared an alternative procedure for the spectral subtraction exploiting the principal component analysis algorithm. Moreover, a
simulated angular differential imaging procedure was also implemented to estimate how the instrument performed once this procedure
was applied at telescope. The capability of the IFS to faithfully retrieve the spectra of the detected faint companions was also
considered.
Results. We found that the application of the updated version of the spectral deconvolution procedure alone, when the algorithm
throughput is properly taken into account, gives us a 5σ limiting contrast of the order of 5 × 10−6 or slightly better. The further application
of the angular differential imaging procedure on these data should allow us to improve the contrast by one order of magnitude
down to around 7×10−7 at a separation of 0.3 arcsec. The application of a principal component analysis procedure that simultaneously
uses spectral and angular data gives comparable results. Finally, we found that the reproducibility of the spectra of the detected faint
companions is greatly improved when angular differential imaging is applied in addition to the spectral deconvolution.

Journal of Radioanalytical and Nuclear Chemistry, 2015

The feasibility of using certified reference materials for the full energy efficiency calibration... more The feasibility of using certified reference materials for the full energy efficiency calibration of p-type coaxial high-purity germanium detectors for the determination of radioactivity in environmental samples is discussed. The main sources of uncertainty are studied and the contributions to the total uncertainty budget for the most intense gamma lines are presented. The correction factors due to self-absorption and true coincidence summing effects are discussed in detail. The calibration procedure is validated for natural and artificial radionuclide determination in different matrices through an internal cross-validation and through the participation in a world-wide open proficiency test.

Geoderma, 2019

Proximal gamma-ray spectroscopy supported by adequate calibration and correction for growing biom... more Proximal gamma-ray spectroscopy supported by adequate calibration and correction for growing biomass is an effective field scale technique for a continuous monitoring of top soil water content dynamics to be potentially employed as a decision support tool for automatic irrigation scheduling. This study demonstrates that this approach has the potential to be one of the best space–time trade-off methods, representing a joining link between punctual and satellite fields of view. The inverse proportionality between soil moisture and gamma signal is theoretically derived taking into account a non-constant correction due to the presence of growing vegetation beneath the detector position. The gamma signal attenuation due to biomass is modelled with a Monte Carlo-based approach in terms of an equivalent water layer which thickness varies in time as the crop evolves during its life-cycle. The reliability and effectiveness of this approach is proved through a 7 months continuous acquisition of terrestrial gamma radiation in a 0.4 ha tomato (Solanum lycopersicum) test field. We demonstrate that a permanent gamma station installed at an agricultural field can reliably probe the water content of the top soil only if systematic effects due to the biomass shielding are properly accounted for. Biomass corrected experimental values of soil water content inferred from radiometric measurements are compared with gravimetric data acquired under different soil moisture levels, resulting in an average percentage relative discrepancy of about 3\% in bare soil condition and of 4\% during the vegetated period. The temporal evolution of corrected soil water content values exhibits a dynamic range coherent with the soil hydraulic properties in terms of wilting point, field capacity and saturation.

IEEE Transactions on Geoscience and Remote Sensing, 2018

In this paper, we present the results of an 5-h airborne gamma-ray survey carried out over the Ty... more In this paper, we present the results of an 5-h airborne gamma-ray survey carried out over the Tyrrhenian Sea in which the height range (77-3066) m has been investigated. Gamma-ray spectroscopy measurements have been performed using the AGRS\_16L detector, a module of four 4L NaI(Tl) crystals. The experimental setup was mounted on the Radgyro, a prototype aircraft designed for multisensorial acquisitions in the field of proximal remote sensing. By acquiring high-statistics spectra over the sea (i.e., in the absence of signals having geological origin) and by spanning a wide spectrum of altitudes, it has been possible to split the measured count rate into a constant aircraft component and a cosmic component exponentially increasing with increasing height. The monitoring of the count rate having pure cosmic origin in the >3-MeV energy region allowed to infer the background count rates in the40K,214Bi, and208Tl photopeaks, which need to be subtracted in processing airborne gamma-ray data in order to estimate the potassium, uranium, and thorium abundances in the ground. Moreover, a calibration procedure has been carried out by implementing the CARI-6P and Excel-based program for calculating atmospheric cosmic ray spectrum dosimetry tools, according to which the annual cosmic effective dose to human population has been linearly related to the measured cosmic count rates.

Atmospheric Environment, 2017

222Rn is a noble radioactive gas produced along the 238U decay chain, which is present in the maj... more 222Rn is a noble radioactive gas produced along the 238U decay chain, which is present in the majority of soils and rocks. As 222Rn is the most relevant source of natural background radiation, understanding its distribution in the environment is of great concern for investigating the health impacts of low-level radioactivity and for supporting regulation of human exposure to ionizing radiation in modern society. At the same time, 222Rn is a widespread atmospheric tracer whose spatial distribution is generally used as a proxy for climate and pollution studies. Airborne gamma-ray spectroscopy (AGRS) always treated 222Rn as a source of background since it affects the indirect estimate of equivalent 238U concentration. In this work the AGRS method is used for the first time for quantifying the presence of 222Rn in the atmosphere and assessing its vertical profile. High statistics radiometric data acquired during an offshore survey are fitted as a superposition of a constant component due to the experimental setup background radioactivity plus a height dependent contribution due to cosmic radiation and atmospheric 222Rn. The refined statistical analysis provides not only a conclusive evidence of AGRS 222Rn detection but also a (0.96 ± 0.07) Bq/m3 222Rn concentration and a (1318 ± 22) m atmospheric layer depth fully compatible with literature data.

Journal of Maps, 2015

We present a detailed map of uranium distribution and its uncertainties in the Variscan Basement ... more We present a detailed map of uranium distribution and its uncertainties in the Variscan Basement of Northeastern Sardinia (VBNS) at a scale of 1:100,000. An area of 2100 km2 was investigated by means of 535 data points obtained from laboratory and in situ gamma-ray spectrometry measurements. These data volume corresponds to the highest sampling density of the European Variscides, aimed at studying the genetic processes of the upper crust potentially triggered by an enrichment of radiogenic heat-producing elements. For the first time, the Kriging with Variance of Measurement Error method was used to assign weights to the input data which are based on the degree of confidence associated with the measurements obtained using different gamma-ray spectrometry techniques. A detailed tuning of the model parameters for the adopted Experimental Semi-Variogram led to the identification of a maximum distance of spatial variability coherent to the observed tendency of the experimental data. We demonstrate that the obtained uranium distribution in the VBNS, characterized by several calc-alkaline plutons emplaced within migmatitic massifs and amphibolite-facies metamorphic rocks, is an excellent benchmark for the study of ‘hot’ collisional chains. The uranium map of VBNS, and in particular the Arzachena minor pluton, confirms the emplacement model based on the recognition of the different petrological associations characterizing the Variscan magmatic processes in the Late Paleozoic. Furthermore, the presented model of the uranium content of the geological bedrock is a potential baseline for future mapping of radon-prone areas.

Education Science, 2019

Although environmental radioactivity is all around us, the collective public imagination often as... more Although environmental radioactivity is all around us, the collective public imagination often associates a negative feeling to this natural phenomenon. To increase the familiarity with this phenomenon we have designed, implemented, and tested an interdisciplinary educational activity for pre-collegiate students in which nuclear engineering and computer science are ancillary to the comprehension of basic physics concepts. Teaching and training experiences are performed by using a 4" × 4" NaI(Tl) detector for in-situ and laboratory γ-ray spectroscopy measurements. Students are asked to directly assemble the experimental setup and to manage the data-taking with a dedicated Android app, which exploits a client-server system that is based on the Bluetooth communication protocol. The acquired γ-ray spectra and the experimental results are analyzed using a multiple-platform software environment and they are finally shared on an open access Web-GIS service. These all-round activities combining theoretical background, hands-on setup operations, data analysis, and critical synthesis of the results were demonstrated to be effective in increasing students' awareness in quantitatively investigating environmental radioactivity. Supporting information to the basic physics concepts provided in this article can be found at http://www.fe.infn.it/radioactivity/ educational. a mixed method that is based on applying nuclear engineering concepts and computer science tools to explore in-situ environmental radioactivity.

Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial ... more Flight height is a fundamental parameter for correcting the gamma signal produced by terrestrial radionuclides measured during airborne surveys. The frontiers of radiometric measurements with UAV require light and accurate altimeters flying at some 10 m from the ground. We equipped an aircraft with seven altimetric sensors (three low-cost GNSS receivers, one inertial measurement unit, one radar altimeter and two barometers) and analyzed ~3 h of data collected over the sea in the (35–2194) m altitude range. At low altitudes (H < 70 m) radar and barometric altimeters provide the best performances, while GNSS data are used only for barometer calibration as they are affected by a large noise due to the multipath from the sea. The ~1 m median standard deviation at 50 m altitude affects the estimation of the ground radioisotope abundances with an uncertainty less than 1.3%. The GNSS double-difference post-processing enhanced significantly the data quality for H > 80 m in terms of both altitude median standard deviation and agreement between the reconstructed and measured GPS antennas distances. Flying at 100 m the estimated uncertainty on the ground total activity due to the uncertainty on the flight height is of the order of 2%.