Misure spettrometriche gamma di concentrazioni radionuclidiche in campioni ambientali e alimentari in situazioni di emergenza

Simulazione di un irradiatore gamma con codice Monte Carlo: valutazione della dose e verifica dei contributi strutturali

Si è utilizzato il codice di calcolo Montecarlo MCNP4C per simulare sia le sorgenti che i materiali strutturali dell’irradiatore IGS3, al fine valutarne i loro contributi. Il numero di storie simulate è stato fissato in modo da ottenere un errore casuale abbastanza piccolo. Si sono utilizzati due scenari: uno in presenza del ripiano di appoggio dei campioni da irradiare ed uno senza. I punti dose sono stati posti a tre distanze dalle sorgenti e a tre quote rispetto al piano di appoggio. Negli stessi punti–dose sono state eseguite delle misure sperimentali utilizzando due coppie di sorgenti di radioattive. Sia le simulazioni che i punti sperimentali sono stati messi in relazione con i risult…

Gamma-ray irradiation tests on CCD and CMOS sensors used in imaging techniques

Technologically-enhanced electronic devices are used in various fields as space imaging or diagnostic techniques in medicine. The devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same apparatus, in particular in space applications. In this paper we report the results of a gamma irradiation tests on imaging sensors simulating the space radiation over a long time period. Two types of sensors are taken into consideration: CCD (Charge-Coupled Device) sensors and CMOS based on technology MOS (Metal Oxide semiconductor) used for the realization of transistors widely used in consumer electronics. The devices are supplied by Techno System (Italy),…

RADIONUCLIDE CONCENTRATIONS IN AIR PARTICULATE AT PALERMO (ITALY) FOLLOWING FUKUSHIMA ACCIDENT

Following the Fukushima accident, a series of samplings were carried out with a daily frequency to detect the arrival of radioactive contamination in air at Palermo (Italy) and to follow its evolution during the time. Air particulate collection was performed by suction of atmospheric air through cellulose filter paper by means of a high-volume air sampler (∼15 000 m(3) d(-1)). Spectrometric analysis of the filters highlights the presence of (131)I, (134)Cs, (137)Cs and, only for a few samples, traces of (132)Te-(132)I and (136)Cs. Maximum airborne concentrations were 883 μBq m(-3) for (131)I (only particulate), 81 μBq m(-3) for (137)Cs and 70 μBq m(-3) for (134)Cs. From a dose to population…

Environmental Radioactivity and Volcanological Features of Three Islands of the Mediterranean Sea (Pantelleria, Ustica and Vulcano)

Abstract The Mediterranean Sea is an area of great interest for its volcanic activities. This paper presents a comparative study of radiometric and chemical data regarding three volcanic islands located in southern Italy (Pantellena, Ustica, and Vulcano) characterized by different magmatic histories. Measurements of radionulide contents and chemical composition of rock samples belonging to the main lithologies present in the three islands were carried out the observed correlations among radiometric, chemical and mineralogical data reflect the differences in the volcanological genesis and suggest some hypotheses on the magmatic evolution.

Seasonal variation of air kerma rate in Sicily.

Thermoluminescence dosimetry has been used to measure air kerma in 29 sites in Sicily. Four three month measurement campaigns have been carried out in order to assess seasonal variations. Average annual values between 20 and 90 nGy h(-1), after cosmic background subtraction, are reported. Average annual values are strongly dependent on site lithology, and we find that winter data are generally the highest, while spring and autumn rates are generally the lowest with very similar trends in any site. Summer values generally lay in between. Largest seasonal variations are found in sites along the southern coast of the island, probably because of stronger action of winds affecting radon, along w…

Measurement of 210Pb airborne activity concentration by gamma-ray spectrometry of air particulate samplings

Lead-210 (half-life 22.3 y), is a natural radionuclide, being produced in the atmosphere through radon decay. Due to its affinity for particles, it is rapidly fixed by aerosols and, with its long half-life is the most important tracer of long range atmospheric aerosol transport and removal processes. Main measurement techniques adopted to evaluate 210Pb air activity concentration differ in analysis and sample preparation methods. Some of them involved complex chemical processes or decay product detection (for example 210Po), with a long decay time period between sampling and experimental measurement. The availability of an high-volume particulate sampler (about 900 m3 h-1) combined with a l…

Measurement of air activity concentrations and comparison with meteorological variables in surface air at Palermo , Italy.

Assessing soil erosion in a small Sicilian basin by caesium-137 measurements and a simplified mass balance model

Abstract The caesium-137 technique affords both an alternative to conventional measurement methods and an effective quantitative estimate of soil redistribution at the basin scale. Among the available calibration relationships which link the degree of increase or depletion of the 137Cs activity relative to the baseline 137Cs input and sediment yield, the mass balance approach has received increased application for its physical basis. First, the applicability of the refined simplified point-based mass balance (RSPMB) model of Zhang et al. (1999) at the scale of the morphological unit is proposed herein. The 137Cs spatial distribution measured in a small Sicilian basin and the spatial distrib…

Seasonal variation of air kerma in the "Vulcano Porto" area (Aeolian Islands, Italy).

Abstract Air kerma was measured in the “Vulcano Porto” area of the Vulcano Island, belonging to the Aeolian Islands, in the Mediterranean Sea. Measurements were carried out using thermoluminescence dosimeters. The relationship between observed dose values and source lithology has been assessed. Data show a seasonal variation due to weather conditions but also probably related to features of the soils, making the variation more evident.

A modular neutron irradiator based on 241Am-Be neutron sources

Neutron irradiator facilities with 241Am-Be sources are worldwide used in order to perform neutron activation analysis (NAA), to investigate materials in different research areas or to test and calibrate neutron detectors and environmental or personal dosemeters. The use of a neutron irradiator is advantageous because of its very stable neutron flux, even it is many orders of magnitude lower than the one of a nuclear reactor or a particle accelerator. Most of irradiators are realized with neutron sources located at fixed positions and accordingly the characteristics of neutron spectrum previously assessed do not change. Therefore, an interesting choice is to have a modular facility, capable…

Gamma activity and geochemical features of building materials: estimation of gamma dose rate and indoor radon levels in Sicily.

A high-purity germanium detector has been used to measure the abundance of radium (Ra), thorium (Th) and potassium (K) in building materials used in Sicilian dwellings. The measurements were performed to evaluate which material was suitable for the construction of an enclosure, which would have a low background emission. The materials examined in this work showed concentrations of 226Ra, 232Th and 40K dramatically variable depending on the lithologies, particularly in the case of blocks, sands and aggregates commonly used in building materials in Sicily. The results are discussed and a criterion is indicated to reduce the radiation dose to humans. Since radon inlet is a major health problem…

Safety and efficacy of ombitasvir/paritaprevir/ritonavir/dasabuvir plus ribavirin in patients over 65 years with HCV genotype 1 cirrhosis

Purpose: To analyse safety and efficacy of treatment based on ombitasvir/paritaprevir/ritonavir/dasabuvir plus ribavirin in the sub-group of GT1 patients older than 65 years. Methods: We collected data extracted from the ABACUS compassionate-use nationwide Italian programme, in patients with cirrhosis due to hepatitis C virus (HCV) Genotype-1 (GT1) or 4 and at high risk of decompensation. GT1-HCV-infected patients received once-daily ombitasvir/paritaprevir, with the pharmacokinetic enhancer ritonavir (25/150/100 mg) and twice-daily dasabuvir (250 mg) plus Ribavirin (RBV) (OBV/PTV/r + DSV + RBV) for 12 (GT1b) or 24 (GT1a) weeks. Endpoints were to evaluate safety and efficacy, the latter def…

Il monitoraggio della radioattività ambientale in Italia: aspetti scientifici, giuridici e normativi. Quaderno No. 1/06, Dipartimento di Ingegneria Nucleare, Università degli Studi di Palermo

Fission Product Activity Measurements in Air Particulate Filters Collected after Fukushima Accident at Palermo, Italy

In the framework of routine operation of AGN-201 COSTANZA Nuclear research reactor, measurements of radionuclide air concentration are periodically performed by filtering an high volume of air through paper filters and by using HPGe gamma-ray spectrometry. After Fukushima accident, a series of samplings was carried out with a daily frequency so to detect the possible arrival of air radioactive contamination and to follow its evolution. Particulate collection was performed by suction of atmospheric air through 45cm × 45cm Sofiltra-Poelman HYN-75 (Bleu type) cellulose filter paper using a high-volume air sampler located on the roof of our department 20 m above ground-level. The sampling time …

Gamma-ray irradiation tests of CMOS sensors used in imaging techniques

Technologically-enhanced electronic image sensors are used in various fields as diagnostic techniques in medicine or space applications. In the latter case the devices can be exposed to intense radiation fluxes over time which may impair the functioning of the same equipment. In this paper we report the results of gamma-ray irradiation tests on CMOS image sensors simulating the space radiation over a long time period. Gamma-ray irradiation tests were car ried out by means of IGS-3 gamma irradiation facility of Palermo Uni ver sity, based on 60Co sources with dif fer ent ac tiv i ties. To re duce the dose rate and re al ize a nar row gamma-ray beam, a lead-collimation sys tem was pur posely …

Valutazione dei fattori di correzione per coincidenze–somma in spettrometria gamma di sorgenti volumetriche.

Temporal trends of heavy metals in sediment core from the gulf of Palermo (Sicily, Italy)

The evaluation of long–term heavy metal concentrations in the Gulf of Palermo was carried out in this study. Measurements of Cr, Cu, Hg, Pb and Zn concentrations were performed by atomic absorption spectrophotometry (AAS) on dated fractions of a sediment core, dated by the 210Pbex method. They are found to cover a time period from 1951 to 2004. The constant sedimentation rate model was used for dating. Specific activities of 137Cs have also been measured in the sediment core sections as a check of the time scale derived by the 210Pbex method. A time-series analysis based on temporal decomposition was used in order to investigate the presence of heavy metal pollution trend. The additive comp…

Una stazione per il monitoraggio on-line di radioattività atmosferica: criteri di progetto e valutazione dei costi

Presso la Sezione di Ingegneria Nucleare del Dipartimento dell’Energia (già Dipartimento di Ingegneria Nucleare, DIN) dell’Università di Palermo, è installato un sistema di aspirazione di particolato atmosferico ad altissimo volume (circa 1000 m3/h di aria). Costruito agli inizi degli anni ottanta del secolo scorso, risulta ormai datato in parte della strumentazione a corredo oltre che nella stessa struttura di protezione dagli agenti atmosferici che lo contiene. La stazione di prelievo è stata utilizzata fino a qualche anno addietro per il monitoraggio giornaliero di deboli concentrazioni di inquinanti radioattivi in aria, con livelli di Minima Attività Rivelabile (MAR) abbastanza ridotti …

MISURE DI RADIOATTIVITA' AMBIENTALE A PALERMO NEL PERIODO 1960 - 2007

Un approccio radiometrico e petrografico per l’analisi di campioni dei monti delle Madonie (Sicilia, Italia)

Una campagna di prelievo nella regione montagnosa delle Madonie (Sicilia) è stata recentemente effettuata per caratterizzare dal punto di vista dosimetrico zone con differenti caratteristiche litologiche. Al termine della campagna sono stati raccolti 41 campioni di terreno e rocce selezionati in base alla loro natura. Tutti i campioni sono stati poi triturati, essiccati e sigillati in beakers "Marinelli" per 20 giorni prima della misura per garantire il raggiungimento dell’equilibrio radioattivo tra 226Ra e 214Bi. Sono stati poi sottoposti a misure spettrometriche gamma con rivelatore a Ge di efficienza 35% per la determinazione delle concentrazioni dei radionuclidi presenti. Le caratterist…

Destino dei radionuclidi negli impianti di depurazione delle acque reflue urbane

Lo studio presentato in questo lavoro ha avuto come obiettivo il monitoraggio e l’analisi del destino dei radionuclidi negli impianti di depurazione ed è stato condotto in collaborazione tra l’Università di Palermo e ARPA Sicilia. Esso ha previsto lo svolgimento di due fasi sperimentali. Nel corso della prima sono stati monitorati gli impianti di depurazione a servizio dei Comuni di Palermo (in località Acqua dei Corsari e Fondo Verde), Bagheria e Cefalù; nella seconda fase l’indagine è stata limitata al solo impianto di Acqua dei Corsari, nel quale si erano riscontrati in precedenza i maggiori spunti di interesse. In entrambe le fasi sono stati prelevati campioni istantanei in diverse sezi…

Natural radioactivity in the Alte Madonie Mounts (Sicily, Italy)

With the collaboration of geology experts, we have taken 45 samples of selected soils and rocks. All samples were powdered, dried and sealed in “Marinelli” beakers for 20 days before the measurement so as to ensure that radioactive equilibrium between 226Ra and 214Bi has been reached. Mineralogical and chemical features of the samples were determined by XRD and XRF analysis, instead Gamma ray spectrometric analysis was used in order to quantify radioactivity concentrations. The average values of concentrations of 214Bi, 228Ac and 40K are respectively 30, 19 and 258 Bq/kg while the greatest values were 134, 59 and 748 Bq/kg. A linear relationship exists between 214Bi, 228Ac and 40K activitie…

MULTIVARIATE STATISTICAL TOOLS FOR THE RADIOMETRIC FEATURES OF VOLCANIC ISLANDS

The Aeolian Islands represents a Quaternary volcanic arc related to the subduction of the Ionian plate beneath the Calabrian Arc. The geochemical variability of the islands has led to a broad spectrum of magma rocks. Volcanic products from calc-alkaline (CA) to calc-alkaline high in potassium (HKCA) are present throughout the Archipelago, but products belonging to shoshonitic (SHO) and potassium (KS) series characterize the southern portion of Lipari, Vulcano and Stromboli. Tectonics also plays an important role in the process of the islands differentiation. In this work, we want to review and cross-analyze the data on Lipari, Stromboli and Vulcano, collected in measurement and sampling cam…

Measurement of activity of the predominant gamma-emitting radionuclides in activated components of a medical cyclotron plan

An identification and activity evaluation of the predominant gamma-emitting radionuclides in activated parts of a medical cyclotron plant by high resolution gamma-ray spectrometry were performed. The use of LaBr3:Ce scintillation and HPGe detectors was examined in order to solve the measurement problems due to high activity of some components used inside a plant provided with an IBA CYCLONE 18/9 cyclotron. For each component, the identification of some key-radionuclides allows to evaluate the surface dose behaviour as function of decay time. The largest activity values are related to radionuclides with half-life of 70-80 days, while radionuclides with higher half-lives represent less than 1…

Virtual point detector: Application to coincidence-summing correction in gamma-ray spectrometry

The use of an efficiency transfer method based on the virtual point detector approximation to evaluate coincidence-summing correction values for point and volume sources was examined. The method was validated by means of a comparison with experimental efficiency determinations.

Sediment delivery processes and the spatial distribution of caesium-137 in a small Sicilian basin

The sediment delivery processes occurring in a small Sicilian basin are modelled using the spatially distributed SEDD model recently proposed by Ferro and Minacapilli. The model is applied by using soil data (grain-size distribution, organic matter content, etc.) of 129 samples uniformly distributed over the study area and compiling the available information (topographic map, soil data, etc.) into a Geographical Information System. Finally, the predictive capability of the distributed sediment delivery approach is tested experimentally using the caesium-137 measurement technique. The comparison between calculated sediment yield and the corresponding measured caesium-137 loss is used to vali…

I radionuclidi nei sedimenti del golfo di Palermo: datazione di una carota prelevata al largo di S. Erasmo.

Valutazione della fluenza di neutroni di origine cosmica a livello del suolo

Lo studio degli effetti delle radiazioni neutroniche sul funzionamento dei componenti che fanno parte dei più comuni sistemi elettronici comporta lo studio della fluenza neutronica di origine cosmica a livello del suolo. Infatti la sorgente primaria dei neutroni in atmosfera è principalmente individuabile nell’interazione tra i raggi cosmici di origine solare ed i vari strati dell’atmosfera. Il campo neutronico pertanto non è dunque costante ma dipende fortemente dai cicli di attività solare. In questo lavoro sono presentati i risultati di due cicli di misurazioni del “dose rate” da neutroni nei periodi 21-28 Febbraio e 29 Febbraio-7 Marzo 2012. La strumentazione utilizzata è costituita dal…

Radionuclides in wastewater treatment plants: monitoring of Sicilian plants.

Three Sicilian wastewater treatment plants were monitored to assess the occurrence and the behaviour of radionuclides. Two sampling campaigns (screening and long-term) were carried out during which liquid and solid samples have been analysed. It was found that 131I mostly occurred in the samples analysed during the screening campaign (43% of the analysed samples contained 131I). High 131I specific activity was found in the mixed liquor, recycled sludge and dehydrated sludge samples. This finding was mainly due to the tendency of 131I to be associated with solid particles. During the long-term sampling campaign an influence of the sludge retention time (SRT) on the 131I behaviour was found. …

Dating of marine sediments by using unsupported 210Pb method

In the framework of a more general study on marine species in sediments, it was necessary to obtain a time calibration of the different sections of the sampled sediment columns, both to estimate the pollution of the sediments and, particularly, to study the migration of foraminifers within the column. The method of the unsupported 210Pb, i.e. whose activity is not derived from the radioactive decay of its 226Ra parent, has been used. Since the activity of the supported 210Pb can be determined from the activity of 226Ra, the unsupported 210Pb activity can be calculated as the difference between 210Pb total and 226Ra activities. The unsupported 210Pb decays with its own half-life time, equal …

La radioattività nel Golfo di Palermo.

MCNP5 MODELLING OF HPGE DETECTORS FOR EFFICIENCY AND COINCIDENCE SUMMING CORRECTION EVALUATIONS IN GAMMA-RAY SPECTROMETRY.

A modelling of HPGe detectors was performed through simulation with the MCNP5 Monte Carlo code. The simulation results concerning the values of the main physical parameters of the detector are in most cases different from those provided by the manufacturer. The use of “single-line” sources allows us to suitably modify the parameter values used in the detector model. For a detector model, the simulation assesses the distribution of photopeak and total efficiency for point sources, whereas for extended sources a control volume approach allows us to determine elementary efficiency behaviours. An integration of elementary efficiencies over the entire sample volume allows us to evaluate global e…

A procedure to evaluate coincidence-summing correction values in gamma-ray spectrometry with HPGe detectors

The spectrometric analysis of a gamma-emitter sample measured in "close geometry" can be affected by errors due to coincidence-summing effects that can occur when two or more coincident photons (real coincidences) within the resolution time of the spectrometric system are emitted. The probability that these effects occur depends primarily on the nuclide decay scheme, the sample-detector distance and detector intrinsic-efficiency whereas results independent from the sample nuclide activity. Coincidence-summing corrections of the photopeak areas are requested, in particular, when the gamma ray spectrometric analysis is aimed to efficiency or activity determination. In this work is reported a …

MISURE SPETTROMETRICHE GAMMA DI IMPUREZZE RADIONUCLIDICHE IN PRODOTTI RADIOFARMACEUTICI IMPIEGATI IN MEDICINA NUCLEARE

La recente approvazione e pubblicazione dell’edizione aggiornata della Farmacopea ufficiale (Decreto del 30 marzo 2005) e l’introduzione di requisiti di purezza dei radiofarmaci, ha condotto a sviluppare una serie di studi e di metodiche per la verifica della purezza radionuclidica di un prodotto radioafarmaceutico. Le Norme di buona preparazione di radiofarmaci in Medicina Nucleare individuano alcune procedure di accertamento e di garanzia della qualità di un prodotto tramite l’impiego di una serie di prove predisposte per valutare parametri fisici, chimici, biologici essenziali per la somministrazione in sicurezza a pazienti. La purezza radionuclidica del radiofarmaco è solitamente valuta…

Inquinamento da metalli pesanti in ambiente marino in correlazione con la distribuzione dei foraminiferi bentonici

Misura di concentrazioni di prodotti di fissione in aria a Palermo a seguito dell’incidente di Fukushima

Nell’ambito del controllo periodico della radioattività ambientale attorno al reattore di ricerca AGN-201 Costanza di questa Università, vengono effettuate di routine rilevazioni di concentrazioni di radionuclidi artificiali e naturali in atmosfera tramite filtrazioni di aria e misure con spettrometria gamma. Dopo la comunicazione dell’incidente di Fukushima (Giappone), conseguente all’evento sismico del 11 marzo 2011 e del successivo devastante “tsunami”, è stata effettuata una serie di campionamenti di particolato atmosferico con frequenza giornaliera in modo da rilevare l’eventuale arrivo su Palermo (e sulla Sicilia) della possibile contaminazione radioattiva in aria e seguirne l’evoluzi…

A Monte Carlo-aided design of a modular 241Am-Be neutron irradiator

Monte Carlo studies aimed at designing a modular 241Am-Be neutron irradiator for testing neutron detectors and personal dosimeters and processing large volume samples are reported in this study. The evaluation of the shapes and thicknesses of the moderator and shielding materials was carried out by a MCNP5 Monte Carlo simulation code. The reliability of the simulation was experimentally verified by the activation of gold foils and TLD dosimeter measurements in an irradiation cell placed at the center of the test configuration.

Valutazioni di efficienza di rivelatori HPGe con il codice MCNP5

Sono presentate alcune simulazioni con il codice MCNP5 di rivelatori di fotoni di tipo HPGe (High Purity Germanium) per la valutazione di efficienze per alcune geometrie usualmente impiegate in misure di tipo radioprotezionistico (Marinelli beakers, a disco, etc). Il modello del rivelatore è validato mediante confronti con determinazioni sperimentali di sorgenti puntiformi calibrate di tipo “single line”, caratterizzate dalla emissione di un solo fotone gamma per disintegrazione. L’ottimizzazione è realizzata valutando in tutto il range energetico di interesse le differenze tra i valori simulati e sperimentali di efficienza, sia fotoelettrica che totale, al variare di alcuni dei parametri c…

Coincidence-summing correction equations in gamma-ray spectrometry with p-type HPGe detectors

Abstract Equations to compute γ−γ and γ−X K coincidence-summing corrections in gamma-ray spectrometry with p-type HPGe detectors are reported. For point sources only full-energy-peak and total efficiencies are needed.

Concentrazioni di gas radon in ambienti lavorativi di diverse regioni italiane

Design and realization of a radon chamber as a secondary standard

The air-radon mixture is the most significant source of natural radiation in workplaces and within dwellings. Despite some uncertainty in the risk estimates, it is widely believed that greater the exposure to radon, greater the risk of developing lung cancer. To assess the radiological hazard, accurate measurements of radon concentrations are necessary. A large variety of radon monitoring instruments have been developed in the last years, usually calibrated in radon chambers containing a known radon concentration released within the chamber by a specific solid radium-226 source. Radon calibration chamber has been constructed to test and calibrate radon and radon progeny detectors at various…

Design of Am-Be neutron irradiator by Monte Carlo simulation

Neutron irradiator facilities with Am-Be sources are worldwide available in order to perform neutron activation analysis (NAA), to investigate materials in different research areas or to test and calibrate neutron detectors and dosemeters. The use of a neutron irradiator is advantageous because have a very stable neutron flux, even it is many orders of magnitude lower than the one of a nuclear reactor or a particle accelerator. Many of irradiators are realized with neutron sources located at fixed positions and accordingly the characteristics of neutron spectrum previously assessed do not change [1]. However, an interesting chance is to have a modular facility, capable of varying conditions…

Experiences of radioactivity measurement in various environmental samples

An overview on our activity of environmental radioactivity measurement is reported. Radionuclide concentration have been evaluated in the particulate air, soils and rocks, drinking and surface water, wastewater, marine sediments and so on. Most of radionuclide concentration evaluation were performed using facilities of DEIM Department of Palermo University. In particular, particulate collection was performed by suction of atmospheric air through 45x45 Sofiltra-Poelman HYN-75 (Bleu type) cellulose filter paper using a high-volume air sampler located on the roof of our department building (20 m above ground-level), located within an undisturbed large park area in the city of Palermo (latitude…

Environmental Radioactivity Measurements in the Mediterranean Area

In the framework of an environmental radioactivity monitoring program, a research activity concerning an optimization of techniques for sampling and measurement of environmental radioactivity was performed at the Nuclear Engineering Department (DIN) of Palermo University. Al-though initially aimed to the analysis of monitoring data of the local network installed at the nuclear research reactor AGN-201 "COSTANZA" of Palermo University, in the following years the studies were oriented to improve the sampling facilities and measurement systems with the aim to achieve also detection limits as low as possible. The activity has allowed to collect numerous data of nuclide activity concentration fo…

Environmental Gamma Radiation Measurements on the Island of Pantelleria

The population exposure to those living on the island of Pantelleria, Italy, was estimated by measuring the natural gamma background. Gamma spectra of natural rocks and measurements of absorbed dose in air were taken. A correlation was found between the mean gamma exposure rate and the mean values of natural radionuclide concentrations in the investigated rocks.

Cyclic influences on the heavy metal chronology in a Central Mediterranean area (Palermo Gulf, Italy)

PurposeThe evaluation of long-term heavy metal concentrations in the Gulf of Palermo (Italy) has been carried out in order to investigate how changes of pollution levels in the last 50 years can be reflected in marine sediments. Measurements of Cr, Cu, Hg, Pb, and Zn concentrations were performed on dated fractions of a sediment core. Time series analysis has allowed to obtain information on the chronology of the heavy metal pollution of the area and to identify seasonal components and trends.Materials and methodsHeavy metal concentrations in the <63 μm fraction of core sections were obtained by Atomic Absorption Spectrophotometry, after wet sieving, drying, and digestion procedures. Dating…

Education and Research in Nuclear Engineering and Radiological Protection at Nuclear Engineering Department of Palermo University

A radiometric and petrographic interpretation of discrepancies on uranium content in samples collected at Alte Madonie Mounts region (Sicily, Italy)

Abstract The main goal of this work is to evaluate a correlation between anomalous Uranium (U) content and petrographic features of some soil and rock samples collected at Alte Madonie Mounts region (North-central Sicily, Italy). A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in “Marinelli” beakers for 20 days before the measurement to ensure that radioactive equilibrium between 226 Ra and 214 Bi was reached. Gamma-ray spectrometric analysis was used to quantify radioactivity concentrations. Mineralogical and chemical features of the samples were determined by X-ray Fluorescence (XRF), X-ray Diffractometry (XRD), Attenuated Total Reflection-Four…

Environmental radioactivity at Stromboli (Aeolian Islands)

HPGe gamma spectrometry, thermoluminescence dosimetry, X-ray diffractometry and fluorescence techniques have been used to analyze the natural radionuclides content of soil and rock samples, air kerma and geochemical features on the island of Stromboli, belonging to the Aeolian Islands, in the Mediterranean Sea. The 214Bi, 238Ac, and 40K contents obtained are in agreement with the magmatic evolution of the rock formation, as shown by the correlations between radionuclide and chemical elements abundacies, depending on the various magmatic differentiation mechanisms. Correlations between radiometric, lithological and geochemical data have been assessed in order to obtain some hints on the geoc…

Numerical expressions for the computation of coincidence-summing correction factors in γ-ray spectrometry with HPGe detectors

Numerical expressions to compute gamma-gamma and gamma-X(K) coincidence summing corrections were deduced by using a suitable computer program and a matrix representation of a decay scheme. For point sources only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be considered with the introduction of "effective efficiencies". Examples of the use of the expressions for point sources and a particulate filter sample measured with a 60% relative efficiency HPGe detector are reported.

Dating of a sediment core in the Palermo Bay (Sicily, Italy)

An extensive study of sediment cores in the Palermo Bay has been carried during the last two years. Main goal of the research was to study the environmental pollution of the area, using foraminifers as an environmental indicator.

UN IRRADIATORE NEUTRONICO MODULARE CON SORGENTI DI 241Am-Be PER IL TEST DI DOSIMETRI NEUTRONICI PERSONALI

Irradiatori neutronici basati su sorgenti radionuclidiche sono impiegati in diversi paesi per l’analisi per attivazione di vari campioni, per studiare le caratteristiche dei materiali sottoposti a irradiazione, ma anche per studiare la risposta di rivelatori e/o dosimetri personali sensibili alla componente neutronica. Per quest’ultima applicazione, l’uso di un irradiatore con sorgenti risulta molto vantaggioso per la stabilità nel tempo del flusso neutronico, mentre è relativamente poco importante il valore assoluto del flusso neutronico, di qualche ordine di grandezza inferiore a quello di reattori o di acceleratori di particelle. Per l’effettuazione di test su rivelatori e/o dosimetri pe…

Taratura di una carota prelevata nel Golfo di Palermo.

Valutazione sperimentale delle componenti del campo di radiazioni in un irradiatore neutronico con sorgenti 241Am-Be e confronto con simulazioni Monte Carlo

Il presente lavoro riguarda la valutazione sperimentale delle componenti gamma e neutronica del campo di radiazioni presente in diversi punti all’interno del canale di irraggiamento di un irradiatore neutronico con sorgenti 241Am-Be. Per la componente gamma sono stati considerati due contributi: il primo associato a gamma di energia di 60 keV, dovuto al decadimento dell'241Am; il secondo a gamma di energia 2,2 MeV, dovuto alla cattura radiativa dei neutroni da parte dello schermo biologico (acqua) che circonda le sorgenti. Per le misure sperimentali sono stati utilizzati dosimetri tipo TLD700 in due diverse configurazioni: TLD "nudi" per misura della dose relativa al campo gamma totale e TL…

Progettazione e realizzazione di un irradiatore neutronico modulare basato su sorgenti Am-Be

Irradiatori neutronici basati su sorgenti radionuclidiche sono impiegati in diversi paesi per studiare le caratteristiche dei materiali sottoposti a irradiazione e/o la risposta di rivelatori e/o dosimetri personali sensibili alla componente neutronica. Per quest’ultima applicazione, l’uso di un irradiatore con sorgenti radionuclidiche risulta molto vantaggioso per la stabilità nel tempo del flusso neutronico, mentre è relativamente poco importante il valore assoluto del flusso neutronico, che può anche essere di qualche ordine di grandezza inferiore a quello di reattori o di acceleratori di particelle. Per l’effettuazione di test su rivelatori e/o dosimetri personali neutronici risulta mol…

Misura della concentrazione di Radon in diverse sedi lavorative distribuite sul territorio nazionale

La camera Radon del Dipartimento di ingegneria Nucleare dell'Università di Palermo

OTTIMIZZAZIONE DI SISTEMI DI RADIOPROTEZIONE IN UN REPARTO PER LA PRODUZIONE DI RADIOFARMACI PER DIAGNOSTICA P.E.T.

In questo lavoro è riportata l’attività di verifica della realizzazione e ottimizzazione delle tecniche, dei dispositivi di protezione e delle procedure operative adottate in un moderno impianto di Diagnostica PET, dotato di ciclotrone per la produzione di radiofarmaci con accelerazione di protoni fino a 16,5 MeV di energia. Con riferimento alla realizzazione di un insediamento all’interno di una Azienda Ospedaliera della città di Palermo, inserita in un contesto cittadino, una analisi approfondita dei sistemi di sicurezza insieme alla identificazione di alcune criticità ha consentito di riconsiderare alcuni dispositivi, anche alla luce di più moderne tecnologie, e di riesaminare l’effettiv…

Sulla misura della concentrazione in aria di 210Pb tramite spettrometria gamma di particolato atmosferico raccolto su filtro

Chemistry, mineralogy and radioactivity inposidonia oceanicameadows from North-Western Sicily

This paper presents measurements of major, minor, metal trace elements and radionuclides in sediments and in Posidonia oceanica samples from north-western Sicily (Italy). The mineralogical and chemical composition of sediments were determined by X-ray diffraction and X-ray fluorescence techniques, respectively. A flame atomic absorption spectrophotometry was used to measure concentrations of Cu, Zn, Cd and Pb in P. oceanica samples and in sediments. Specific activities of selected radionuclides have been determined by high-resolution gamma spectrometry. Standard statistical analysis was used to assess correlations between different elements and different sample types.

A chamber to test the response of radon detectors to changing environmental conditions.

Radon risk assessment is carried out with accurate measurements with active or passive instrumentation. All radon detectors must be calibrated and tested using a radon chamber containing a known concentration of radon produced by specific sources of 226Ra. Some of the chambers can also be used to test the response of detectors as a function of environmental conditions. In this case, it can be inferred a calibration curve with respect to changing of the parameter considered. For this aim, a new chamber radon was designed and realized to perform both calibration of instruments and to study the detector response in a large range of variation of the environmental parameters (pressure, 700 - 110…

Correlation of radioactivity measurements, air kerma rates and geological features of Sicily

Abstract Sicily, the largest Mediterranean island (with an extension of about 25 000 km 2 ), exhibits a very wide variety of lithologies, ranging from sedimentary to metamorphic and volcanic rocks. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied to air kerma values measured by thermoluminescent dosimetry in several sites and to data of radionuclide concentrations, geochemical and mineralogical features of rocks and soils sampled in 29 sites of Sicily to point out similarities among different lithologies. The study was devoted to find multiple correlations and allow a better classification of Sicilian lithotypes. Samples of rocks and soils have be…

Uno studio per l’implementazione della strumentazione della stazione di prelievo di particolato atmosferico del DIN di Palermo

Dating of a Sediment Core by 210Pbex Method and Pb Pollution Chronology in the Palermo Gulf (Italy)

Within a more general study on marine sediments in the Gulf of Palermo (Sicily, Italy), the 210Pbex dating method (using a model with constant sedimentation rate) has been applied to one sediment core. The main goal of the research was to study the Pb pollution chronology. Dating of the core has allowed evaluating the time evolution of the gulf lead concentrations. Specific activities of 137Cs have also been measured in the sediment core sections as an independent confirmation of the chronology derived by the 210Pbex method. The time scale has then been used to correlate lead concentrations in core sections to estimated lead emissions in air due to gasoline combustion. A good correlation be…

Volcanic products of Lipari (Aeolian islands, Italy): Multivariate analysis of petrographic and radiometric data

Abstract A petrographic and radiometric study, along with statistical multivariate analysis of volcanic products of the island of Lipari (Aeolian islands, Italy) was carried out. The volcanological history of Lipari was reconstructed defining two stages (pre- and post-erosive stages) further on subdivided in four volcanic phases, each of which characterized by products with a particular chemical composition and separated by stratigraphic unconformities. The correlations between petrographic features, determined by X-ray fluorescence, and volcanological history of the island highlight a gradual differentiation with younger rocks showing a more acid chemical composition than the older ones. R…

Characteristics of coronary microcirculatory function in patients with Takotsubo syndrome.

Background: Takotsubo syndrome (TS) is a recently described cardiac syndrome whose pathogenesis is still unclear. We investigated the characteristics of coronary microcirculatory function in patients with TS through the analysis of the TIMI frame count (TFC) compared to normal subjects and with to subjects with microvascular angina (MA). Methods: We enrolled 71 TS patients (F:M =69:2, mean age of 65.27±9.53 years), 70 controls (F:M =34:36, mean age of 56.63±13.5 years) and 71 patients with MA, (F:M =69:2, mean age of 65.9±9.2 years). The assessment of the microcirculation was carried out through the TFC. Results: microcirculation was significantly altered in patients with TS compared with h…

Impiego della tecnica del cesio -137 per il monitoraggio dei processi erosivi nel bacino SPA2

Evaluation Of 210Pb Air Activity Concentration By Direct Gamma Ray Spectrometry Of Air Particulate Samplings.

A radiometric and petrographic approach to risk assessment at Alte Madonie Mounts region (Sicily, Italy)

The main goal of this work was to assess the radiological hazard at Alte Madonie Mounts region (north-central Sicily, Italy) in response to rumours of an increase in the incidence of cancer in this area. A correlation between the natural radionuclide contents and the petrographic features of the soil and rock samples was also evaluated. A total of 41 samples of selected soils and rocks were collected, powdered, dried and sealed in 'Marinelli' beakers for 20 d prior to measurement to ensure that a radioactive equilibrium between (226)Ra and (214)Bi had been reached. A gamma-ray spectrometer was used to quantify the radioactivity concentrations. To determine (238)U and (232)Th activities, the…

Impiego di un sistema spettrometrico gamma portatile basato su uno scintillatore LaBr3(Ce)

La risoluzione energetica di uno scintillatore LaBr3(Ce) è decisamente superiore (<3% a 662 keV) rispetto a quella di un più tradizionale scintillatore NaI(Tl) anche se ancora decisamente non comparabile con quella dei rivelatori a Ge. Questa caratteristica del rivelatore, oltre il ridotto tempo di risposta, lo rende adatto per misure “in situ” specialmente quando è importante l’individuazione rapida in uno spettro gamma di manifestazioni fotoelettriche con energia molto prossime tra loro (individuazione di sorgenti o rifiuti radioattivi, misure nel campo delle salvaguardie nucleari, …). Una significativa limitazione nel suo impiego è tuttavia rappresentata dalla elevata radioattività intri…

Attivita’ di misura delle concentrazioni di radionuclidi naturali gamma-emittenti nel particolato atmosferico a Palermo

Gamma-ray spectrometyric characterization of waste activated target components in a PET Cyclotron

Piani di Sicurezza per il trasferimento di sorgenti di radiazioni gamma e neutroni ad alta attività

La movimentazione di sorgenti ad alta attività, sia che si tratti dell’acquisizione, trasporto e collocazione di nuove sorgenti in impianti di irraggiamento, o del trasferimento di sorgenti all’interno della stessa struttura, deve essere pianificata nei minimi dettagli con un piano di lavoro. Ciò è fondamentale per l’analisi di tipo radioprotezionistico ma anche dal punto di vista della valutazione dei rischi di altra natura, non ultima la movimentazione dei carichi. Tale analisi preventiva viene effettuata avvalendosi sinergicamente di un gruppo di esperti con diverse competenze e varie figure di responsabilità (Responsabile delle sorgenti, RSPP, Esperto Qualificato, Medico Autorizzato, …)…

Natural radioactivity in a volcanic island: Ustica, Southern Italy

Abstract Gamma-ray spectrometric measurements were performed on rocks and soils of the island of Ustica (Southern Italy) to quantify the concentrations of the natural radionuclides. The 238U, 232Th, and 40K concentration ranges (15–164, 16–174, and 201–1350 Bq kg−1, respectively) were compared with mineralogical and chemical data obtained by XRD and XRF analyses. The observed levels of the primordial radionuclides corresponded to the magmatological features of the rocks. Soil samples generally showed specific gamma-ray activities not directly correlatable to those measured in the underlying rocks. A survey was also perormed to measure air kerma in outdoor and indoor environments using therm…

Application of Monte Carlo simulation to design a modular 241Am-Be neutron irradiator

Most of neutron irradiators are realized with neutron sources located at fixed positions and accordingly the characteristics of neutron spectrum previously assessed do not change. However, an interesting chance is to have a modular facility, capable of varying conditions of irradiation and setting the prevalence of fast or thermal neutron spectrum components. In this work we report the Monte Carlo studies devoted to design a modular 241Am-Be neutron irradiator making use of different moderators (water, graphite, polyethylene and so on) in order to obtain a neutron energy distribution useful to test neutron detectors or personal dosemeters. The optimization of thicknesses and shape of the mo…

Ombitasvir, paritaprevir, and ritonavir, with or without dasabuvir, plus ribavirin for patients with hepatitis C virus genotype 1 or 4 infection with cirrhosis (ABACUS): a prospective observational study

Summary Background We ran a compassionate use nationwide programme (ABACUS) to provide access to ombitasvir, paritaprevir, and ritonavir, with dasabuvir, plus ribavirin for hepatitis C virus (HCV) genotype 1 infection and ombitasvir, paritaprevir, and ritonavir, plus ribavirin for HCV genotype 4 infection in patients with cirrhosis at high risk of decompensation while approval of these regimens was pending in Italy. Methods In this prospective observational study, we collected data from a compassionate use nationwide programme from March 17, 2014, to May 28, 2015. Patients with HCV genotype 1 infection and cirrhosis at high risk of decompensation were given coformulated ombitasvir (25 mg), …