University of Insubria Archives

Background removal procedure based on the SNIP algorithm for γ-ray spectroscopy with the CAEN Educational Kit

November 12th, 2021| |CAEN Experiments, Particle Detectors Characterization

In gamma spectra the energy, the intensity and the number of resolved photo peaks depend on the detector resolution and the background from physics processes. A widely used method for subtracting the background under a photopeak is provided by the Sensitive Nonlinear Iterative Peak (SNIP) algorithm. This paper reports a validation procedure of the SNIP algorithm, based on the invariance of the photo-peak area for different background levels.

A simple and robust method to study after-pulses in Silicon Photomultipliers

November 12th, 2021| |CAEN Experiments, Particle Detectors Characterization

The after-pulsing probability in Silicon Photomultipliers and its time constant are obtained measuring the mean number of photo-electrons in a variable time window following a light pulse. The method, experimentally simple and statistically robust due to the use of the Central Limit Theorem, has been applied to an HAMAMATSU MPPC S10362-11-100C.

An Educational Kit Based on Modular Silicon Photomultiplier System

November 12th, 2021| |CAEN Experiments, Particle Detectors Characterization

Silicon Photo-Multipliers (SiPM) are state of the art light detectors with unprecedented single photon sensitivity and photon number resolving capability, representing a breakthrough in several fundamental and applied Science domains. An educational experiment based on a SiPM set-up is proposed in this article, guiding the student towards a comprehensive knowledge of this sensor technology while experiencing the quantum nature of light and exploring the statistical properties of the light pulses emitted by a LED

The EasyPET: a novel concept for an educational cost-effective positron emission 2D scanner

September 24th, 2021| |CAEN Experiments, Nuclear Imaging - PET, Nuclear Physics and Radioactivity, Nuclear Physics and Radioactivity

The EasyPET concept proposed here, protected under a patent by the University of Aveiro, aims to realize a simple and affordable small dimension Positron Emission Tomography (PET) scanner. This innovative system is based on a single pair of detectors and a rotating mechanism with two degrees of freedom reproducing the functionalities of an entire PET ring. A 2D imaging prototype has been designed, commissioned and engineered, targeted to high level education for physics, engineering and nuclear medicine students. In this paper the performance of the prototype is reported, with a focus on the imaging capability and on the measurement of the uncertainty in the reconstruction of the source position. In addition, a detailed analysis is dedicated to the slice sensitivity and in particular to the effect of the energy threshold on the coincidence event selection.

Silicon Photomultipliers and SPAD imagers in biophotonics: Advances and perspectives

September 24th, 2021| |Advanced Statistics, CAEN Experiments, Silicon Photomultipliers

Photonics is essential in life science research and the continuous development of methods offers researchers tools of unprecedented sensitivity. Sensors are key to the exploitation of the most advanced biophotonic techniques with highly demanding specifications in terms of single photon sensitivity, time resolution, miniaturisation real-time processing and data throughput. Silicon photomultipliers and Single Photon Avalanche Diode (SPAD) imagers represent the state-of-the-art in photon detection with single photon sensitivity, photon number resolving capability and the possibility to integrate on chip advanced functionalities. As a consequence, they can be the platform for the next generation biophotonic instruments and methods. This paper summarises the main biophotonic techniques and reports exemplary applications of Silicon Photomultipliers and SPAD imagers for fluorescence, chemiluminescence, time correlated single photon counting and imaging. Achievements and current limitations are addressed, pointing as well to the most recent technology advances and highlighting the possible pathways for the near future.

CAEN Educational: Nuclear and Particle Physics Experiments

September 24th, 2021| |CAEN Experiments, Cosmic Rays, Nuclear Physics and Radioactivity, Particle Physics, Photons

CAEN S.p.A., an important industrial spin-off of the INFN (National Institute for Nuclear Physics), is pleased to present its new activities in the educational field. CAEN brings the experience acquired in almost 40 years of collaboration with the High Energy & Nuclear Physics community into the university educational laboratories by providing modern physics experiments based on the latest technologies and instrumentation. CAEN has realized different modular Educational Kits, all based on Silicon Photomultipliers (SiPM) state of-the-art light sensors with single photon sensitivity and unprecedented photon number resolving capability. They have proven to be suitable for an increasing number of applications in science and industry. The main goal is to inspire students and guide them towards the analysis and comprehension of different physics phenomena with a series of experiments based on state-of-the art technologies, instruments and methods.

Cosmic ray Telescope

Samuela LomazziSeptember 24th, 2021| |CAEN Experiments, Cosmic Rays

The existence of cosmic rays was discovered by Victor Hess in 1912, performing experiments on the ionization of the air. The cosmic radiation is composed by ener-getic particles mainly originating outside the Solar System and even from distant galaxies. It could be divided into two component: “primary” and “secondary”. Of primary cosmic rays, which originate outside of Earth’s atmosphere, about 99% are the nuclei of well-known atoms and about 1% are solitary electrons. Of the nuclei, about 90% are protons, 9% are alpha particles and 1% are the nuclei of heavier elements. A very small fraction are stable particles of antimatter, such as positrons or antiprotons. When cosmic rays penetrate the Earth’s atmosphere they collide with atoms and molecules, mainly oxygen and nitrogen. The interaction produces a cascade of lighter particles, a so-called shower secondary radiation, including protons, x-rays, muons, alpha particles, pions, electrons, and neutrons (figure 1). In first approximation about of 30% of the secondary radiation is composed by electrons and photons, while the 70% by muons.

Caratterizzazione fotorivelatore SiPM s13360-1350cs

September 24th, 2021| |CAEN Experiments, Particle Detector Characterization, Particle Detectors Characterization, Silicon Photomultipliers

Un fotodiodo a valanga (Avalanche Photo Diode APD), schematizzato in figura 1, è un particolare fotodiodo caratterizzato da quattro strati di semiconduttore drogati asimmetricamente. 1. La zona p+, molto drogata, con Na1 accettori (accettori/ μm3 > 105); 2. La zona i(p−), intrinseca, utile a tenere pressochè costante il campo elettrico, a migliorare l’efficienza quantica QE (numero di cariche elettriche rilasciate per ciascun quanto di luce assorbito) e a diminuire la capacità di giunzione; 3. La zona p, drogata con Na2 accettori (con Na1 < Na2); 4. La zona n+, caratterizzata dalla presenza di molti atomi Nd donatori (donatori/μm3 > 105)

Laboratorio di Fisica 1

September 24th, 2021| |CAEN Experiments, Nuclear Physics and Radioactivity, Nuclear Physics and Radioactivity, Particle Detector Characterization, Silicon Photomultipliers

Il radon è un gas radioattivo, inodore, incolore e insapore; tutte caratteristiche che non lo rendono percepibile dai nostri sensi e perciò difficile da individuare e da quantificarne la presenza. Esso, derivato dal decadimento dell’uranio presente nelle rocce e nel suolo, si trova principalmente nei locali, specie quelli a diretto contatto con il suolo, come cantine e scantinati, con possibilità tuttavia di arrivare ad irradiarsi anche negli ambienti dei piani più alti. Il pericolo maggiore del gas radon è correlato all’inalazione: inspirato in quantitativi in eccesso e per periodi prolungati può infatti provocare seri danni alla salute, in particolare ai polmoni, qualificandosi come seconda causa di rischio per l’insorgenza di un tumore, dopo il fumo. La prima prevenzione per combattere questo gas è la costante areazione dei locali nei quali è riconosciuta la sua presenza

SiPM: fotomoltiplicatore al Silicio

Prof. Massimo Luigi Maria CacciaSeptember 24th, 2021| |CAEN Experiments, Particle Detector Characterization, Particle Detectors Characterization, Silicon Photomultipliers

L’occhio può essere considerato come il primo rivelatore di radiazione luminosa, captando luce dall’ambiente esterno e trasformando questo input in un segnale elettrico che funge da impulso nervoso per il cervello. In base all’essere vivente preso in considerazione la sensibilità di questo organo e la risposta allo stimolo luminoso variano notevolmente. Con lo sviluppo della ﬁsica è comparsa l’esigenza di strumenti che fossero in grado di rilevare la radiazione luminosa, talvolta anche sotto forma di pochi fotoni (non sempre così facilmente osservabili dall’occhio umano). Un esempio signiﬁcativo riguardo questa necessità nello sviluppo ﬁsico risale allo sﬁntariscopio di Crooks (1903), uno schermo di Solfuro di Zinco che colpito da particelle α emette una debole luce. Inizialmente l’osservazione era eﬀettuata ad occhio, contando le scintille emesse osservando il fenomeno con un microscopio in una stanza buia. Nel 1944 Curran e Baker sostituirono l’occhio umano con un fotomoltiplicatore (PM) in modo da rendere la lettura più facile e con un’aﬃdabilità deﬁnita. Questo strumento è in grado di convertire un segnale luminoso in un segnale elettrico. L’ampliﬁcazione è proporzionale al segnale in ingresso.

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