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Questa tesi è una monografia sull'uso del rilevatore a stato solido di carburo di silicio (SiC) come contatore e spettrometro di neutroni veloci per le applicazioni di plasmi da fusione. In essa sono illustrate le attività di ricerca condotte su una serie di prototipi SiC per caratterizzarli, contribuendo al loro sviluppo e alla valutazione del loro potenziale. La rilevazione dei neutroni è il principale modo per ottenere informazioni su un plasma a fusione in un tokamak. Attraverso di essa è possibile determinare la potenza di fusione, individuare la forma e la densità del plasma e stimare la produzione di trizio nel breeding blanket. Misurando lo spettro energetico dei neutroni è inoltre possibile dedurre altre proprietà del plasma, come il rapporto tra deuterio e trizio o la temperatura ionica. Tuttavia, il contesto pone sfide senza precedenti per le diagnostiche: elevati flussi di neutroni, la presenza di intensi campi magnetici, temperature elevate e alti livelli di radiazione. I rilevatori allo stato solido basati sul SiC presentano caratteristiche molto promettenti per affrontare tali sfide. Poiché il SiC è un design di rilevatore a stato solido relativamente inesplorato, le attività di ricerca di questo progetto di dottorato hanno avuto lo scopo di caratterizzare una serie di prototipi SiC, sviluppati in collaborazione con IMM-CNR, individuando i loro punti di forza rispetto allo stato dell'arte dei rilevatori a stato solido, il rilevatore a diamante. Nel corso dell’attività sono stati caratterizzati otto prototipi di SiC mediante irraggiamento di neutroni e particelle cariche. Sono stati anche sviluppati metodi per l'analisi dei dati, la gestione dell'elettronica, la manifattura della componentistica ed altro ancora. Le caratteristiche del rilevatore (efficienza, risoluzione energetica, stabilità ed altro) sono state studiate in diverse configurazioni, individuando metodi per migliorarle e utilizzando i risultati come base per la produzione di n, This thesis is a monography on the use of Silicon Carbide (SiC) Solid State Detector (SSD) as a fast neutron counter and spectrometer for fusion plasma applications. It details the research activities conducted on a series of SiC prototypes to characterize them, contributing to their development and assessment of their potential. Neutron detection is possibly the main way of obtaining information on a fusion plasma in a Tokamak. Through it is possible to determine the fusion power, determine the plasma location and density and estimate the production of tritium in the breeder elements. By measuring the neutron energy spectrum it is also possible to infer other plasma properties, like the fuel ion ratio or the ion temperature. Tokamak environments, though, put unprecedented challenges on the diagnostics: large neutron fluxes, the presence of intense magnetic fields, high temperatures, and intense radiation. SSDs feature very promising characteristics for handling the aforementioned challenges. Since the SiC is a relatively unexplored SSD design, the research activities of this PhD project aimed to characterize a series of SiC prototypes, developed in conjunction with IMM-CNR, finding their strengths compared to the state of art of SSDs, the diamond detector. The activity has been dedicated to characterization of eight prototypes through neutron and charged particles irradiation, developing methods for data analysis, electronics management, hardware manufacturing and more. Detection characteristics (efficiency, energy resolution, stability and more) were studied in different configurations, finding methods to improve them and using the results as a basis for the manufacturing of new, improved prototypes. Stress tests were also conducted under harsh conditions, highlighting the functionality of the detector in harsh environments. Unprecedented methods of operations, like the partial depletion detection, were also experimented, finding new beneficial uses for the detect

Questa tesi è una monografia sull'uso del rilevatore a stato solido di carburo di silicio (SiC) come contatore e spettrometro di neutroni veloci per le applicazioni di plasmi da fusione. In essa sono illustrate le attività di ricerca condotte su una serie di prototipi SiC per caratterizzarli, contribuendo al loro sviluppo e alla valutazione del loro potenziale. La rilevazione dei neutroni è il principale modo per ottenere informazioni su un plasma a fusione in un tokamak. Attraverso di essa è possibile determinare la potenza di fusione, individuare la forma e la densità del plasma e stimare la produzione di trizio nel breeding blanket. Misurando lo spettro energetico dei neutroni è inoltre possibile dedurre altre proprietà del plasma, come il rapporto tra deuterio e trizio o la temperatura ionica. Tuttavia, il contesto pone sfide senza precedenti per le diagnostiche: elevati flussi di neutroni, la presenza di intensi campi magnetici, temperature elevate e alti livelli di radiazione. I rilevatori allo stato solido basati sul SiC presentano caratteristiche molto promettenti per affrontare tali sfide. Poiché il SiC è un design di rilevatore a stato solido relativamente inesplorato, le attività di ricerca di questo progetto di dottorato hanno avuto lo scopo di caratterizzare una serie di prototipi SiC, sviluppati in collaborazione con IMM-CNR, individuando i loro punti di forza rispetto allo stato dell'arte dei rilevatori a stato solido, il rilevatore a diamante. Nel corso dell’attività sono stati caratterizzati otto prototipi di SiC mediante irraggiamento di neutroni e particelle cariche. Sono stati anche sviluppati metodi per l'analisi dei dati, la gestione dell'elettronica, la manifattura della componentistica ed altro ancora. Le caratteristiche del rilevatore (efficienza, risoluzione energetica, stabilità ed altro) sono state studiate in diverse configurazioni, individuando metodi per migliorarle e utilizzando i risultati come base per la produzione di n, This thesis is a monography on the use of Silicon Carbide (SiC) Solid State Detector (SSD) as a fast neutron counter and spectrometer for fusion plasma applications. It details the research activities conducted on a series of SiC prototypes to characterize them, contributing to their development and assessment of their potential. Neutron detection is possibly the main way of obtaining information on a fusion plasma in a Tokamak. Through it is possible to determine the fusion power, determine the plasma location and density and estimate the production of tritium in the breeder elements. By measuring the neutron energy spectrum it is also possible to infer other plasma properties, like the fuel ion ratio or the ion temperature. Tokamak environments, though, put unprecedented challenges on the diagnostics: large neutron fluxes, the presence of intense magnetic fields, high temperatures, and intense radiation. SSDs feature very promising characteristics for handling the aforementioned challenges. Since the SiC is a relatively unexplored SSD design, the research activities of this PhD project aimed to characterize a series of SiC prototypes, developed in conjunction with IMM-CNR, finding their strengths compared to the state of art of SSDs, the diamond detector. The activity has been dedicated to characterization of eight prototypes through neutron and charged particles irradiation, developing methods for data analysis, electronics management, hardware manufacturing and more. Detection characteristics (efficiency, energy resolution, stability and more) were studied in different configurations, finding methods to improve them and using the results as a basis for the manufacturing of new, improved prototypes. Stress tests were also conducted under harsh conditions, highlighting the functionality of the detector in harsh environments. Unprecedented methods of operations, like the partial depletion detection, were also experimented, finding new beneficial uses for the detect

The MITICA experiment, under construction at Consorzio RFX (Padova, Italy), is the full-scale prototype for the Neutral Beam Injector (NBI) of the ITER tokamak. One of the critical aspects for the ion beam accelerator is high voltage holding over long vacuum gaps (up to 1 MV from the ion source to the enclosing vessel), with the main issue being the occurrence of discharge events, which could severely damage the machine. To study this phenomenology, with the aim of prevention of discharges, the High Voltage Padova Test Facility (HVPTF) experiment is in operation. The setup of HVPTF consists in a cylindrical vacuum vessel, with stable pressure control, in which two replaceable electrodes are mounted with an adjustable gap width. The electrodes are powered by independent power supplies, allowing for a total voltage difference up to 800kV. Current and voltage of the power supplies, as well as the pressure and the gas composition inside the chamber are monitored at a sampling rate of 100 Hz. Additionally, the bremsstrahlung X-ray emission produced by the accelerated electrons during discharges is monitored by means of scintillators at higher rates (up to 1 MHz). Data from past experimental campaigns have been analyzed and correlations between the current/voltage signals and the X-ray emission have been highlighted. Recently, a new detector, based on the Gas Electron Multiplier (GEM) and optimized for X-ray detection, has been installed at HVPTF. The detector acts as a very fast single photon counting system (with rates up to about 125 MHz), allowing for real-time measurement of the X-ray emission rate, which could be used as basis for the development of a feedback control system for the prevention of discharges. The aim of this work is to illustrate the development of a new data analysis software, tailored on the data read by the GEM detector, displaying some of the first results obtained from the recent experimental campaigns. Future perspectives will also be drawn, fo

The gas recycle is nowadays an important issue for gaseous detectors operation under study and for this reason, scientists are testing new gas systems for GEM detectors. Since some gas purifier does not allow to use oxygen, the standard Ar-CO2 (70%-30%) cannot be used; thus, new gas mixtures are under investigation. This paper presents the study of a triple GEM detector filled with new gas mixture based on Argon and Nitrogen (Ar-N2) at different concentrations: 90%-10%, 80%-20% and 70%-30%. The GEM detector characterisation has provided the High Voltage working point for the gas mixtures and a comparison between the Ar-CO2 and the Ar-N2.

In this paper we present the design of a photon pre-amplifier based on a photo-cathode coated Thick Gas Electron Multiplier (THGEM). Such device is crucial in application where a weak light signal produced in a radiation detector must be amplified so that it can be carried to a photo-detector by means of optical fibres. An example of a device where a light signal must be amplified is a gamma-ray Cherenkov detector for fusion power measurements in magnetic confinement devices. In such application the active part of the detector must be located very close the plasma, typically in a harsh radiation environment where standard photodetectors cannot operate. The photon pre-amplifier allows to increase the signal generated in the active part of the detector so that it can be easily detected by the photodetector located outside the harsh environment. We present the conceptual design of a THGEM based photon pre-amplifier supported by Garfield++ simulations. The device working principle is the following: primary photons impinge on the photo-cathode and extract electrons that are accelerated by the THGEM electric field. Upon collisions with the accelerated electrons, the gas molecules in the pre-amplifier are brought to excited states and de-excite emitting scintillation photons. Since each electron excites multiple gas molecules, the scintillation photons outnumber the primary photons, leading to the amplification. In addition, we present the first observation of measurements of Nitrogen gas scintillation in a THGEM device. We devised an experimental setup consisting of a vacuum chamber containing a THGEM and an alpha particle source. The vacuum chamber is filled with pure nitrogen and is coupled to a photomultiplier tube via a view-port to detect the scintillation photons generated in the THGEM. For sake of simplicity the electrons that induce the scintillation are generated by the ionization track of an alpha particle rather than by the THGEM photo-cathode coating. A good q

In fusion plasma scenario, soft X-rays are important tools to study impurities inside plasma. However state-of-the-art silicon detectors cannot survive for long time to the heavy damages due to harsh conditions in tokamaks. GEM detectors are a good alternative thanks to their resilience to radiation damage. In this paper, a GEM detector coupled with new dedicated electronic readout based on GEMINI chip is described. In particular, the detector response has been studied comparing the well established PH method and the ToT method implemented in GEMINI. The results indicate the possibility of using this electronic readout to do soft X-ray spectroscopy measurements in the energy range up to about 10-20 keV.

The development of MITICA, the prototype for a neutral beam injector for ITER, drives the interest in investigating high HV insulation in vacuum. The High Voltage Padova Test Facility (HVPTF) is an experimental device with the aim of studying the fundamental processes leading to discharges, offering a framework to develop new diagnostics, models, and mode of operations for MITICA. For this purpose, HVPTF features a vacuum chamber containing two electrodes which can achieve an HV difference up to 800 kV. X-ray bremsstrahlung radiation produced by free charges accelerated by the HV was proven to be a promising monitoring mechanism in the past; as such, two scintillating crystals, a LYSO and a LaBr3, coupled with fast electronics were used to conduct hard X-ray spectroscopy. This work describes a newly custom-developed software tool to analyze the spectroscopy from scintillators and integrate it with the HVPTF analog data. The tool was employed to study two experimental sessions, reaching promising results in the characterization of microdischarges, especially in terms of time resolution. Detection limits imposed by pile-up and other processes were identified and addressed, finding the best range of operation of the two scintillators. The performed study opens the way for the analysis of data obtained in all 2020 and 2021 experimental campaigns, thus giving the possibility to implement future improvements in HVPTF X-ray spectroscopy.

The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.

The use of wide-band-gap solid-state neutron detectors is expanding in environments where a compact size and high radiation hardness are needed, such as spallation neutron sources and next-generation fusion machines. Silicon carbide is a very promising material for use as a neutron detector in these fields because of its high resistance to radiation, fast response time, stability and good energy resolution. In this paper, measurements were performed with neutrons from the ISIS spallation source with two different silicon carbide detectors together with stability measurements performed in a laboratory under alpha-particle irradiation for one week. Some consideration to the impact of the casing of the detector on the detector’s counting rate is given. In addition, the detector response to Deuterium-Deuterium (D-D) fusion neutrons is described by comparing neutron measurements at the Frascati Neutron Generator with a GEANT4 simulation. The good stability measurements and the assessment of the detector response function indicate that such a detector can be used as both a neutron counter and spectrometer for 2–4 MeV neutrons. Furthermore, the absence of polarization effects during neutron and alpha irradiation makes silicon carbide an interesting alternative to diamond detectors for fast neutron detection.

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. The MVM has obtained Emergency Use Authorization by U.S. Food and Drug Administration (FDA) for use in healthcare settings during the COVID-19 pandemic and Health Canada Medical Device Authorization for Importation or Sale, under Interim Order for Use in Relation to COVID-19. Following these certifications, mass production is ongoing and distribution is under way in several countries. The MVM was designed, tested, prepared for certification, and mass produced in the space of a few months by a unique collaboration of respiratory healthcare professionals and experimental physicists, working with industrial partners, and is an excellent ventilator candidate for this pandemic anywhere in the world.

Dedicated nuclear diagnostics have been designed, developed, and built within EUROFUSION enhancement programs in the last ten years for installation at the Joint European Torus and capable of operation in high power Deuterium-Tritium (DT) plasmas. The recent DT Experiment campaign, called DTE2, has been successfully carried out in the second half of 2021 and provides a unique opportunity to evaluate the performance of the new nuclear diagnostics and for an understanding of their behavior in the record high 14 MeV neutron yields (up to 4.7 × 1018 n/s) and total number of neutrons (up to 2 × 1019 n) achieved on a tokamak. In this work, we will focus on the 14 MeV high resolution neutron spectrometers based on artificial diamonds which, for the first time, have extensively been used to measure 14 MeV DT neutron spectra with unprecedented energy resolution (Full Width at Half Maximum of ≈1% at 14 MeV). The work will describe their long-term stability and operation over the DTE2 campaign as well as their performance as neutron spectrometers in terms of achieved energy resolution and high rate capability. This important experience will be used to outline the concept of a spectroscopic neutron camera for the SPARC tokamak. The proposed neutron camera will be the first one to feature the dual capability to measure (i) the 2.5 and 14 MeV neutron emissivity profile via the conventional neutron detectors based on liquid or plastics scintillators and (ii) the 14 MeV neutron spectral emission via the use of high-resolution diamond-based spectrometers. The new opportunities opened by the spectroscopic neutron camera to measure plasma parameters will be discussed.