RadioLab project: knowledge of radon gas in Italy.

RadioLab is an Italian project, addressed to school-age people, and designed for the dissemination of scientific culture on the theme of environmental radioactivity, with particular regards to the importance of knowledge of radon gas exposure. The project is a nationwide initiative promoted by the National Institute of Nuclear Physics- INFN. First tool used by the project, and of immediate impact to assess the public awareness on radon, is the administration of the survey "do you know the radon gas?". In the survey, together with the knowledge of radon and of its sources, information on personal, cultural and territorial details regarding the interviewees are also taken. Reasonably, the survey invests not only young people, but also their relatives, school workers and, gradually, the public. The survey is administrated during exhibitions or outreach events devoted to schools, but also open to the public. The survey is in dual form: printed and online. The online mode clearly leads RadioLab project even outside the school environment. Based on the results of the survey, several statistical analyses have been performed and many conclusions are drawn about the knowledge of the population on the radon risk. The RadioLab benefit and the requirement to carry on the project goals, spreading awareness of environmental radioactivity from radon, emerge. The dataset involves all twenty Italian regions and consists of 28,612 entries covering the 5-year period 2018-2022.

Absorbed dose evaluation of a blood irradiator with alanine, TLD-100 and ionization chamber.

Irradiation of blood bags using X-ray irradiators and dosimetry services are required to ensure uniform dose levels in the range 25-50 Gy to prevent Transfusion Associated Graft versus Host Disease (TA-GvHD). An absorbed dose characterization of a Raycell MK2 X-Irradiator was performed using three different dosimetric systems. Results showed a dosimetric accuracy of the ionization chamber together with the Alanine dosimeter. TLDs measurements exhibited a small overestimation by 4% of the absorbed dose. The Dose Uniformity Ratio (DUR), between maximum and minimum dose levels in the canister, was in good agreement with the manufacturer specifications (≤1.5).

Search for Lepton Number and Flavor Violation in K

Searches for the lepton number violating K^{+}→π^{-}µ^{+}e^{+} decay and the lepton flavor violating K^{+}→π^{+}µ^{-}e^{+} and π^{0}→µ^{-}e^{+} decays are reported using data collected by the NA62 experiment at CERN in 2017-2018. No evidence for these decays is found and upper limits of the branching ratios are obtained at 90% confidence level: B(K^{+}→π^{-}µ^{+}e^{+})<4.2×10^{-11}, B(K^{+}→π^{+}µ^{-}e^{+})<6.6×10^{-11} and B(π^{0}→µ^{-}e^{+})<3.2×10^{-10}. These results improve by 1 order of magnitude over previous results for these decay modes.

A new cylindrical borehole detector for radiographic imaging with muons.

Muon radiography is a methodology which enables measuring the mass distribution within large objects. It exploits the abundant flux of cosmic muons and uses detectors with different technologies depending on the application. As the sensitive surface and geometric acceptance are two fundamental parameters for increasing the collection of muons, the optimization of the detectors is very significant. Here we show a potentially innovative detector of size and shape suitable to be inserted inside a borehole, that optimizes the sensitive area and maximizes the angular acceptance thanks to its cylindrical geometry obtained using plastic arc-shaped scintillators. Good spatial resolution is obtained with a reasonable number of channels. The dimensions of the detector make it ideal for use in 25 cm diameter wells. Detailed simulations based on Monte Carlo methods show great cavity detection capability. The detector has been tested in the laboratory, achieving overall excellent performance.

Development of radon transport model in different types of dwellings to assess indoor activity concentration.

The influence of different building types on the activity concentration of Radon indoor is studied through transport models in soil and building materials. The numerical solutions of the relevant transport equations are solved by the finite differences method (FDM) and used to evaluate the indoor Radon activity concentration. Several boundary conditions are introduced to simulate the Radon entry into the buildings from soils and to assess the Radon activity concentration at the different floors. The types of dwelling investigated differ in the position of the lower floor respect to the ground. Comparisons are made to modeling assessments obtained considering different soil characteristics underneath the building and building materials to simulate indoor Radon activity concentration. These investigations lead to the conclusion that, in addition to the nature of the soil and building materials, the position of lower floor of dwellings plays a significant role in determining the amount of radon entry into residential buildings. This work is effective to assess the health hazards coming from the Radon accumulation in living environments.

ANALYSIS BY SCANNER OF TRACKS PRODUCED BY RADON ALPHA PARTICLES IN CR-39 DETECTORS.

The most used passive detectors for Radon measurement are the CR39s, both for the good stability of the material and for the practicality of use. But, commercial reading systems are expensive and not always fast. The aim of the present work was the development of a method for a rapid, efficient and economic evaluation of the result of the indoor Radon measurement performed with CR39 detectors. The analysis and acquisition of detector images were performed using a photo scanner and the free ImageJ software. Several groups of CR-39 detectors were exposed, developed and analysed. Calibration curve was obtained in a wide range of exposure values (200-12 000 kBq·h·m -3) to allow the procedure to be applied in all possible measurement environments. Furthermore, a statistical study was carried out on the shape and size of nuclear tracks after chemical development. The dependence of the track size on Radon exposure was effective in showing the trace saturation effect as well.

STUDY OF 222RN CONTINUOUS MONITORING TIME SERIES AND DOSE ASSESSMENT IN SIX EUROPEAN CAVES.

The present work aims to assess the effective doses from long-term continual radon monitoring in six European caves (Slovenia, Slovakia and the Czech Republic), including influencing environmental factors. Caves are important radiation protection subjects because of elevated radon activity concentration (~kBq/m3), mostly due to the low natural ventilation. The sources of radon gas are most often underground rock layers and clastic sediments. The radon activity concentrations show seasonal variations, for which the outside temperature is the main driving force. The human health impact due to the radon inhalation in monitored caves was estimated through the annual effective dose, using the methodology provided by the International Commission on Radiological Protection (ICRP Publication 137). The annual effective dose could reach several tens of mSv, depending on the working hours spent in the underground.

Connection between 222Rn emission and geophysical-geochemical parameters recorded during the volcanic unrest at Campi Flegrei caldera (2011-2017).

Studies concerning 222Rn emission from soils are growing interest in the Earth Sciences, due to the gas potential as a tracer of natural phenomena. This paper presents a study of radon monitoring in two sites of Campi Flegrei caldera (Neaples, Italy) during the period July 1, 2011-December 31, 2017. This area was characterized by several phases of volcanic unrest. A hybrid method based on Multiple Linear Regression + Remote Radon Estimation method + Singular Spectrum Analysis (MLR + RRE + SSA) is developed for the trend extraction and the identification of anomalies in the time series of 222Rn. The results are compared with several routinely used geo-indicators of the caldera unrest. The comparisons show strong correlation among the signals. The present study proves the 222Rn is a potential indicator of the evolution of a volcanic crisis.

Development and calibration of a method for direct measurement of 220Rn (thoron) activity concentration.

The interest in the measurement of thoron (220Rn) activity concentration in air has recently increased, with the attention for the development of standards useful for the calibration of measuring instruments. Due to its short half-life (55.8 s), consolidated techniques for the realization and the use of controlled atmospheres of radon (222Rn) are not effective in the case of thoron. New adequate methodology are required. A method for the measurement of the thoron reference activity based on the direct detection of the alpha particles produced by the decay of 220Rn, from natural samples containing 232Th, is here proposed. The possibility of observing an acceptable spectrum is entrusted to the realization of measurement chambers small enough to reduce as much as possible the energy loss of the alpha particles before they reach the Silicon detector. Such a chamber was realized and used with a known thoron atmosphere in a controlled environment. The experimental results are compared with those obtained from the simulation with the Monte Carlo method: (i) the alpha spectra coming directly from thoron atoms exhibit similar shape with a linear trend plus an exponential trend on the left side of the 220Rn peak, depending from the distance between source and detector; (ii) the corresponding 220Rn detection efficiency values are compatible considering the uncertainties. An investigation was conducted to study the shape of the 220Rn spectra vs the different volume of chambers, through Monte Carlo simulations. The results show: (i) the linear part of the spectra shape goes to reduce with the increasing of the height of the chamber; (ii) the 220Rn detection efficiency decreases with the increasing of the height of the chamber.

Analysis of 7-years Radon time series at Campi Flegrei area (Naples, Italy) using artificial neural network method.

This paper reports the analysis of soil 222Rn data recorded over 7-years in the volcanic caldera of Campi Flegrei (Naples-Italy). The relationship between Radon activity concentration and several geophysical, geochemical and meteorological parameters, influencing the gas emissions, is estimated by the Artificial Neural Network (ANN) method. The analysis goals are: the estimation (replication) of the Radon time series from influencing parameters, the forecasting of an unknown part of it, and the search for anomalies. Results prove: (i) the effectiveness of the ANN method; (ii) Radon follow the periods of agitation of the caldera, demonstrated by the comparison with previous works using different methods.

Continuous radon monitoring during seven years of volcanic unrest at Campi Flegrei caldera (Italy).

This is a seven-year study (1/7/2011-31/12/2017) of radon monitoring at two sites of Campi Flegrei caldera (Neaples, Southern Italy) that in the last 70 years experienced repeated phases of volcanic unrest. The sites are equipped with devices for radon detection, based on the spectrometry analysis of the α-particles of radon daughters. A hybrid method, as combination of three known methods, is applied for the identification of residuals (anomalies) and trends of the time series of Radon. The results are compared with the following indicators of current caldera unrest: the tremor caused by the major fumarolic vent registered by a seismic station; the cumulative of background seismicity; the maximum vertical deformation acquired by GPS networks during the current phase of uplift; the temperature-pressure of the hydrothermal system estimated based on gas geo-indicators. The comparisons show strong correlation among independent signals and suggest that the extension of the area affected by current Campi Flegrei crisis is larger than the area of seismicity and of intense hydrothermal activity from which the radon stations are 1-4 km away. These results represent an absolute novelty in the study of a such calderic area and mark a significant step forward in the use and interpretation of the radon signal.

Analysis of geophysical and meteorological parameters influencing 222Rn activity concentration in Mladec caves (Czech Republic) and in soils of Phlegrean Fields caldera (Italy).

The present work concerns a detailed analysis of Radon time series to differentiate endogenous from exogenous phenomena which provide anomalous signals. Two-year data from two sites in Czech Republic and in Italy are analyzed in order to contribute to the prevention of natural hazards. A new hybrid forecasting method is implemented and tuned for the identification of Radon anomalies in the time series. It is based on the combination of Multiple Linear Regressions, Empirical Mode Decomposition and Support Vector Regression methods that decompose the signal and analyze the components to distinguish the variations due to Radon originated in depths from those due to environmental parameters. The possible correlations with fumarolic tremors in the Italian site and the faults microdisplacements in the Czech site have been studied, as well as with the earthquakes that have influence on two studied areas. Results show that: (i) the used method is very effective considering the calculated statistical uncertainties; (ii) the outer temperature is the main influencing Radon driving force; (iii) the extracted Radon anomalies due to endogenous phenomena are well correlated with fault displacements, fumarolic tremors, and with earthquakes under a characteristic delay time for each area; (iv) significant correlations among earthquake magnitude and depth with fault displacement and fumarolic tremor are found.

Applications of muon absorption radiography to the fields of archaeology and civil engineering.

Muon radiography, also known as muography, is an imaging technique that provides information on the mass density distribution inside large objects. Muons are naturally produced in the interactions of cosmic rays in the Earth's atmosphere. The physical process exploited by muography is the attenuation of the muon flux, that depends on the thickness and density of matter that muons cross in the course of their trajectory. A particle detector with tracking capability allows the measurement of the muons flux as a function of the muon direction. The comparison of the measured muon flux with the expected one gives information on the distribution of the density of matter, in particular, on the presence of cavities. In this article, the measurement performed at Mt. Echia in Naples (Saracino 2017 Sci. Rep. 7, 1181. (doi:10.1038/s41598-017-01277-3)), will be discussed as a practical example of the possible application of muography in archaeology and civil engineering.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.

Volcanoes in Italy and the role of muon radiography.

Cosmic-ray muon radiography (muography), an imaging technique that can provide measurements of rock densities within the top few 100 m of a volcanic cone, has now achieved a spatial resolution of the order of 10 m in optimal detection conditions. Muography provides images of the top region of a volcano edifice with a resolution that is considerably better than that typically achieved with other conventional methods (i.e. gravimetric). We expect such precise measurements, to provide us with information on anomalies in the rock density distribution, which can be affected by dense lava conduits, low-density magma supply paths or the compression with the depth of the overlying soil. The MUon RAdiography of VESuvius (MURAVES) project is now in its final phase of construction and deployment. Up to four muon hodoscopes, each with a surface of roughly 1 m2, will be installed on the slope of Vesuvius and take data for at least 12 months. We will use the muographic profiles, combined with data from gravimetric and seismic measurement campaigns, to determine the stratigraphy of the lava plug at the bottom of the Vesuvius crater, in order to infer potential eruption pathways. While the MURAVES project unfolds, others are using emulsion detectors on Stromboli to study the lava conduits at the top of the volcano. These measurements are ongoing: they have completed two measurement campaigns and are now performing the first data analysis.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.

SIGNAL DECOMPOSITION AND ANALYSIS FOR THE IDENTIFICATION OF PERIODIC AND ANOMALOUS PHENOMENA IN RADON TIME-SERIES.

This work concerns continuous monitoring of radon and thoron specific activity in soil gas within the framework of identifying possible anomalies. It is based on the analysis of a medium-term data record obtained from soil gas in an area of geophysical interest. The RaMonA spectrometric system is also used to measure the climatic parameters and a specific analysis of the alpha spectra is performed to better determine the alpha lines intensity. Since radon emission is also influenced by meteorological parameters, it is mandatory to differentiate the changes due to the deep phenomena. Different procedures are utilized to reach the above objective: statistical analysis using the Empirical Mode Decomposition technique, the Multiple Linear Regression method and the Remote Radon Estimation by using of the thoron trend to eliminate the locally produced radon fraction. The results of such methods are compared to recognize and to highlight radon anomalies.

Imaging of underground cavities with cosmic-ray muons from observations at Mt. Echia (Naples).

Muography is an imaging technique based on the measurement of absorption profiles for muons as they pass through rocks and earth. Muons are produced in the interactions of high-energy cosmic rays in the Earth's atmosphere. The technique is conceptually similar to usual X-ray radiography, but with extended capabilities of investigating over much larger thicknesses of matter thanks to the penetrating power of high-energy muons. Over the centuries a complex system of cavities has been excavated in the yellow tuff of Mt. Echia, the site of the earliest settlement of the city of Naples in the 8th century BC. A new generation muon detector designed by us, was installed under a total rock overburden of about 40 metres. A 26 days pilot run provided about 14 millions of muon events. A comparison of the measured and expected muon fluxes improved the knowledge of the average rock density. The observation of known cavities proved the validity of the muographic technique. Hints on the existence of a so far unknown cavity was obtained. The success of the investigation reported here demonstrates the substantial progress of muography in underground imaging and is likely to open new avenues for its widespread utilisation.

Analysis of alpha particles spectra of the Radon and Thoron progenies generated by an electrostatic collection detector using new software.

A complete and detailed analysis of alpha spectra from the 222Rn and 220Rn progenies was performed by newly developed software. The software identifies the alpha peaks, performs appropriate fits and calculates the net area and its uncertainty, considering the entire background. The deconvolution of the overlapped peaks of 218Po and 212Bi allows us also to evaluate their minimum detectable area. The efficiency of the electrostatic detection method was recalculated and new useful considerations on the collected alpha emitters were made.

[Jejunal perforation from metastatic choriocarcinoma. Case report and review of the literature]. / Perforazione digiunale da coriocarcinoma metastatico. Caso clinico e revisione della letteratura.

Choriocarcinoma is a rare malignant genital tract tumor, arising in the uterus or in the testis. Primary or metastatic choriocarcinomas of the gastrointestinal tract are infrequent. We report a case of a testis choriocarcinoma presenting as jejunal metastasis with perforation. Histology revealed the origin of this metastatic tumor, allowing us to recognize the primary neoplasm of the testis. A review of literature with PubMed since 1964 and of the references of the papers retrieved was performed. Since 1933 only 30 cases of jejunal choriocarcinomas have been described in literature. In 13 cases jejunal choriocarcinoma presented gastrointestinal hemorrhage, in 4 intestinal intussusception and in 1 case upper abdominal pain and vomiting. Only 5 cases of jejunal perforation have been described. The case presented is the first in literature of jejunal perforation from a metastatic choriocarcinoma of the testis.

[Upper gastrointestinal hemorrhage of unusual etiology: clinical case and technical note]. / Emorragia digestiva alta da causa rara: caso clinico e note di tecnica.

The Authors report a case of upper digestive tract haemorrhage at atypical side, the diagnosis being often difficult as well as therapeutical options, particularly referent to the surgical solutions adopted.