Il fenomeno della superconduttività

In questa nota divulgativa sono presentate le proprietà fenomenologiche della fase superconduttrice quali la resistenza elettrica nulla, l’espulsione del campo magnetico o effetto ‘Meissner’, il concetto di campo magnetico critico e supercorrente critica, gli ordini di grandezza delle variabili fisiche coinvolte puntualizzando le tappe storiche della superconduttività. Si mostra il differente comportamento fra un superconduttore e un conduttore perfetto e sono introdotte le due classi di materiali superconduttori e le differenti strutture cristalline. Inoltre si accenna cosa è un quanto di flusso magnetico, le conseguenze dovute alla quantizzazione del campo magnetico in un superconduttore. Brevemente si presenta la speculazione che delinea i fondamenti microscopici del fenomeno superconduttivo: la teoria ‘BCS’ e il concetto della formazione delle coppie di ‘Cooper’. Infine è accennata la descrizione della transizione di fase da uno stato normale a quello superconduttore come “rottura spontanea della simmetria”, concetto elegante e potente usato in modo generale per la comprensione di molteplici fenomeni fisici

Prevention and Preparedness of the Messina-Reggio Calabria Strait: An Earthquake Forecasting and Didactic Project

This contribution is addressed to an introductive university course on the correlation existing between radon emission and earthquakes processes held following a flipped-class approach where students receive didactic materials prior to face-to-face lessons. This research was initially started to investigate the real correlation between Radon emission from the Earth and the occurrence of strong earthquakes by using measurements of hourly Radon flow variation. During quiet seismogenic conditions, we observe an unvarying level of Radon emission in the air. Before a strong earthquake, substantial variations of Radon (222Rn) concentration have been observed in the air, probably because of the increase of thermodynamic energy inside the Earth. The physical processes affecting earthquakes are still not fully understood; therefore, we are interested in investigating a wide variety of signals observed before an earthquake, ranging from chemical, electric, and magnetic variations. The goal is to be able to estimate the earthquake magnitude, timing also location in advance with a good approximation. The experimental observation and research studies were carried out by G. Giuliani Permanent Foundation since 2002 in Abruzzo. The innovative methodology of observations with Gamma detectors allowed us to reveal a close correlation between the different physical phenomena during the preparation phase of strong earthquakes. We master the methodology of measuring the hourly flow of 222Rn gas decay, which provides a good correlation with the occurrence of strong earthquakes. To advance the reliability of our assessment, we added more parameters to our observations, such as magnetic and RF. The joint analysis advances our understanding of the processes underlying the earthquake occurrence. The experimental observation of Radon has been tested for more than a decade in the Abruzzo region. The initial results provided the baseline of reliable correlation between radon variations and earthquakes that could be used as an alert mechanism for the forthcoming seismic events. The multiparametric approach of detecting pre-earthquakes signals provided the robustness in detecting the earthquake preparation phase. There are no doubts that by expanding the network of gamma sensors, we achieve much better signal detection, which is critical for the better spatial correlation of Radon variations with the earthquake processes

A Novel Particle/Photon Detector Based on a Superconducting Proximity Array of Nanodots

The current frontiers in the investigation of high-energy particles demand for new detection methods. Higher sensitivity to low-energy deposition, high-energy resolution to identify events and improve the background rejection, and large detector masses have to be developed to detect even an individual particle that weakly interacts with ordinary matter. Here, we will describe the concept and the layout of a novel superconducting proximity array which show dynamic vortex Mott insulator to metal transitions, as an ultra-sensitive compact radiation-particle detector

Proximity array device: a novel photon detector working in long wavelengths

We present here an innovative photon detector based on the proximity junction array device (PAD) working at long wavelengths. We show that the vortex dynamics in PAD undergoes a transition from a Mott insulator to a vortex metal state by application of an external magnetic field. The PAD also evidences a Josephson I-V characteristic with the external field dependent tunneling current. At high applied currents, we observe a dissipative regime in which the vortex dynamics is dominated by the quasi-particle contribution from the normal metal. The PAD has a relatively high photo-response even at frequencies below the expected characteristic frequency while, its superconducting properties such as the order parameter and the Josephson characteristic frequency can be modulated via external fields to widen the detection band. This device represents a promising and reliable candidate for new high-sensitivity long-wavelength detectors. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Clinical features and lifestyle of patients with amyotrophic lateral sclerosis in Campania: brief overview of an Italian database

Background. Physical activity and occupational exposures appeared to play a relevant role in pathogenesis of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease of unknown origin. Materials and methods. We aimed to make an overview of the clinical characteristics and life - style (occupation and sport) of a population of 395 patients with ALS from campania, in southern Italy. Results. ALS onset resulted anticipated of about 11 years in industry workers, whilst the more frequent site of onset among farmers was upper limbs. compared to non-athletes, athletes, particu- larly soccer players, showed a 7 years anticipation of ALS onset, with higher mortality after 5 years. Discussion and conclusions. We suggest that subjects genetically prone to abnormal response to hy - poxia during strenuous physical activity or exposed to neurotoxic agents, such as athletes, farmers or industry workers, might present increased risk to develop ALS. Future case-control and follow-up studies on our population should be implemented to deepen the present results. Riassunto (Caratteristiche cliniche e stile di vita di pazienti con sclerosi laterale amiotrofica in Campania: breve panoramica di un database italiano). Introduzione. Attivita fisica ed esposizione professionale a sostanze tossiche sembrano svolgere un ruolo rilevante nella patogenesi della sclerosi laterale amiotrofica (SLA), una malattia neurodegenerativa di origine sconosciuta. Materiali e metodi. ci siamo proposti di effettuare una panoramica delle caratteristiche cliniche e dello stile di vita (attivita lavorativa e sport) di una popolazione di 395 pazienti affetti da SLA provenienti dalla regione campania, in Italia meridionale. Risultati. L'insorgenza della SLA e risultata anticipata di circa 11 anni nei lavoratori dell'industria, mentre il sito piu frequente di insorgenza tra i contadini era caratterizzato dagli arti superiori. Rispetto ai non- sportivi, gli sportivi, soprattutto i calciatori, hanno mostrato un'anticipazione di 7 anni nell'insorgenza della SLA, con maggiore mortalita a 5 anni. Discussione e conclusioni. Abbiamo ipotizzato che i soggetti geneticamente predisposti a risposte anomale all'ipossia durante l'attivita fisica intensa o esposti ad agenti neurotossici, come gli sportivi, gli agricoltori o i lavoratori dell'industria, possano presentare un aumen - tato rischio di sviluppare la SLA. Futuri studi caso-controllo e di follow-up sulla nostra popolazione dovrebbero essere effettuati per approfondire i risultati attuali

The future search for low-frequency axions and new physics with the FLASH resonant cavity experiment at Frascati National Laboratories

We present a proposal for a new experiment, the FINUDA magnet for Light Axion SearcH (FLASH), a large resonant-cavity haloscope in a high static magnetic field which is planned to probe new physics in the form of dark matter (DM) axions, scalar fields, chameleons, hidden photons, as well as high frequency gravitational waves (GWs). Concerning the QCD axion, FLASH will search for these particles as the DM in the mass range (0.49-1.49) ueV, thus filling the mass gap between the ranges covered by other planned searches. A dedicated Microstrip SQUID operating at ultra-cryogenic temperatures will amplify the signal. The frequency range accessible overlaps with the Very High Frequency (VHF) range of the radio wave spectrum and allows for a search in GWs in the frequency range (100-300) MHz. The experiment will make use of the cryogenic plant and magnet of the FINUDA experiment at INFN Frascati National Laboratories near Rome (Italy); the operations needed to restore the functionalities of the apparatus are currently underway. We present the setup of the experiment and the sensitivity forecasts for the detection of axions, scalar fields, chameleons, hidden photons, and GWs