Mario Edoardo Bertaina Department of Physics Via P. Giuria 1 -10125 Torino Tel. 011-670.7492, Fax 011-670.7497 E-mail: bertaina@to.infn.it Office Location: New Building - 4th Floor - Room D12 Reception time: WEB PAGE IN: ITALIAN

Research activity

• My research activity is mainly devoted to Ultra-High and Extreme Energy Cosmic Rays (UHECRs and EECRs). However, at the same time it has important interdisciplinary aspects which go from astrophysics to fundamental physics, from advanced technology to environmental physics. Within this framework I'm involved in topics related to cosmogenic neutrinos and peculiar forms of dark matter.
  Right now I participate to two main projects related to UHECRs and EECRs: JEM-EUSO and Auger. At the same time I follow other projects on different scientific themes but connected to the above ones because they use the same technology or methodology developed for the astro-particle physics.
  (Please have a look at video1 which describes the journey of a UHECR produced in an AGN which reaches the Earth and it is detected by an air-shower array, in this specific case by the Pierre Auger Observatory.)
  
  

  • Pierre Auger Observatory (study of primary cosmic rays with energies above 10¹⁷ eV )

    The objective of the Pierre Auger Observatory in the pampa of Argentina is the study of primary cosmic rays with energies above 10¹⁷ eV.
    The energy range between 10¹⁷ and 10¹⁹ eV is particularly interesting because recent theories suggest that this is the range of energies in which the transition between galactic and extra-galactic radiation occurs.
    At higher energies the flux drops down significantly reaching values of the order of one particle per km² per century at energies higher than 5x10¹⁹ eV due to the interaction of the primary cosmic rays with the microwave background radiation. Nevertheless this is the range of energies where it is expected that the astrophysical sources of cosmic rays will show up as the UHECR here produced are only slightly deflected by the extra-galactic magnetic fields.
    The Auger experiment covers an area of 3000 km² and it consists of an array of surface detectors which measure the Cherenkov light emission by particles of the Extensive Air-Shower (EAS) that hit the detectors. At the same time fluorescence telescopes operating at night time detect the fluorescence light emission produced by the EAS in atmopshere while crossing it. The Auger experiment which is collecting data since the years 2000 is currently in an upgrade phase with the objective of taking data till 2025. It represents the largest observatory in the world and it is the result of a common effort of 18 countries around the world.
    (Please have a look to video2 showing the principle of observation of an UHECR by the Pierre Auger Observatory.)
    
    
    

  • JEM-EUSO Program (study of cosmic ray physics, astrophysics, fundamental physics and neutrinos at energies above 10²⁰ eV; observation of atmospheric phenomena such as meteors and lightning; characterization of the cloud coverage at planetary level and study of the space-atmosphere interactions)

    (download the pamphlet explaining the concept of JEM-EUSO observation and/or look at the movie explaining the docking of the telescope to the International Space Station)
    The objective of the JEM-EUSO (Extreme Universe Space Observatory) program is to detect and study cosmic rays at energies above the GZK cutoff, about 10²⁰ eV, which is the energy threshold above which particles start interacting with the microwave background photons (2.7 K). At such energies the cosmic rays are only moderately deflected by the magnetic fields outside and inside our galaxy and can point to the sources that produced them. It becomes, therefore, possible to start performing charged particle astronomy. The final objective of the JEM-EUSO program is to collect in 3-5 years of data taking, about 1000 events at energies above 5x10¹⁹ eV which is a few times more than what can be done from ground like using the Auger experiment. Consequently, it will be possible to have a better understanding if EECRs are produced in sources such as Gamma-ray Bursts, Active Galactic Nuclei, pulsars or black hole collissions in super massive Radio Galaxies.
    Aside from cosmic ray science, JEM-EUSO will be able to detect neutrinos of similar energies. No event has been observed so far at extreme energies due to the extreme low probability that neutrinos have to interact with current detectors due to their limited mass. JEM-EUSO will observe those events because the Earth represents a huge detector which makes the interaction of a few particles per year possible and therefore their detection. Thanks to its enormous field of view JEM-EUSO will be able to search for specific forms of dark matter or strange quark matter such as the so called nuclearites which have been proposed in the past, however never observed. They consist of nuclei containing strange quarks which could have been created during the life of the universe and that could pervade it. Even a null detection will allow to set much more stringent limits on their flux compared to the current ones.
    JEM-EUSO has other scientific explorative objectives which go from problems of fundamental physics, to those of astrophysiscs or planetary science, from atmospheric physics to climate science. Indeed, data acquired by JEM-EUSO will be used to get information on the local galactic and extra-galactic magnetic field, as well as to test relativity and fundamental physics laws at energies which are a few orders of magnitude higher than what can be done with the most powerful accelerators such as LHC. Regarding planetology it will be possible to draw an inventory and size distribution of the interplanetary meteoroids located in the solar system, it will be possible to study the impact phenomena of meteorites and of the interaction of their dust with clouds and their radiative properties in atmosphere. For what concerns more specific atmospheric phenomena it will be possible monitoring the cloud coverage and air transparency, measuring cloud top and optical depth, as well as other cloud properties. It will be possible to further advance on the knowledge of the space-atmosphere interactions and the correlated climated changes, study the convective system at mesoscale level, monitor the aerosols in the low atmosphere, defining their role in causing thunderstorms. Finally, it will be possible to monitor and try to understand the origin of lumionus transients such as elves, sprites and gamma-ray flashes of terrestrial origin.
    The JEM-EUSO program is characterized by several missions from ground ( EUSO-TA in Utah), from stratospheric balloons ( EUSO-Balloon , EUSO-SPB and EUSO-SPB2), with experiments on the International Space Station ( Mini-EUSO , K-EUSO ) and on satellites ( TUS , POEMMA ). Some of them are currently in data taking (EUSO-TA and TUS), for others the data analysis is still on going (EUSO-Balloon and EUSO-SPB), whicle others are in the development phase (Mini-EUSO ed EUSO-SPB2), and others are still at design level (K-EUSO and POEMMA).
    
    
    
  • Other projects:

    EEE : The EEE Project - The Science in the Schools

    The EEE project consists in a particular research activity performed in collaboration with CERN, INFN and MIUR, on the origin of cosmic rays, involving High School students and teachers.
    Each school participating to the project builds one "telescope" made with the most modern and advanced particle detectors (Multigap Resistive Plate Chambers, MRPC), with a GPS system in coincidence with those of the telescopes in the other schools to detect muons and air-showers which have the size as big as towns and cities, produced by ultra-high energy cosmic rays.
    The Physics Department of the University of Torino and the Torino INFN Section will host the EEE station associated to the 'Gobetti-Segre' High School. This station, which is currently in the assembling phase, will become part of the Torino and Italy network.
    Despite the fact that one important goal of this project is educational, EEE represents an array which has the size of Italy and therefore capable of recording events which would release a coincidence signal on vast areas. It represents therefore an eye on the cosmo to detect extreme energy events ever registered on Earth. In this sense, EEE represents a complementary methodology to the one used by Auger and JEM-EUSO to study the extreme universe by means of cosmic rays.
    

    PRISMA : A first network for a systematic monitoring of meteors and the atmosphere.

    The PRISMA project intends to form an Italian network of all-sky cameras to observe bright meteors and fireballs, with the aim of determining the orbits of the parent objects that cause them and define with quite a good accuracy the sights where the fireballs fall to be able to recover the meteorites. The systematic monitoring of the cloud coverage and of the electric activity will be used to validate meoteorological models. Sistematically collected data will contribute to refine the models used to describe the interaction of the cosmic bodies with the atmosphere which nowadays are not complete due to the lack of high quality data.
    This project is lead by researchers of the National Institute of Astrophysics (INAF) and Universities, in collaboration with amateur groups and regional and national Astronomical and Meteorological Observatories. High Schools are involved as well in the project with laboratory activities related to astronomy which are meant to have the students and citizens involved in research activites together with the researchers. This part of the project is called PRISMA-Edu.
    The PRISMA network is quite important for the intended meteor measurements from space within the JEM-EUSO program. The possible fireball observation from ground and from space in different spectral bandwidths (PRISMA works in the visible range while JEM-EUSO in the near ultraviolet one) will allow to collect more precise informations on their characteristics, as well as observe the same phenomenon from different perspectives which allows an intercalibration in the response of different sensors.

    Space Debris : Development of detectors for space debris mitigation adopting the same technology employed in astro-particle physics

    With space debris we indicate all the man made objects which orbit around the Earth and which are not considered useful anymore. To this category belong: rockets, fragments of satellites, dust, material ejected by rocket engines, refrigerating liquid released from the RORSAT nuclear satellite as well as other small particels.
    Space debris increased enormously in the last years, becoming a real problem for the high probability of collisions with active satellites which would produce on their turn other debris. The impact with small debris could be destructive due to the high orbital speed. Some space vehicles, like the International Space Station (ISS) are equipped with special protections to mitigate this type of events. On the other hand extra-vehiclar activities are particularly prone to this problem. The space debris in the range 1 - 10 cm of diameter are partcularly problematic as it's difficult to detect them and they can cause enormous damages as they travel extremely fast (about 30000 km/hour) if we think at the ISS orbital speed.
    This project inherits the experience and the knowledge developed within the JEM-EUSO program, showing how a typical experiment of fundamental science can trigger technological development of a wider interest. The idea is to use detectors and electronics commonly used in astro-particle physics to detect cosmic rays during night, with the aim of detect small space debris and by means of powerful laser systems deorbiting them. This project from one side is performed in collaboration with the Thales Alenia Space company, and with the PRISMA network on the other side as space debris have orbital speeds not too far away from meteor speeds. Therefore, data collected on fireballs and bright meteors could be used to test the response of algorithms to be employed in the detection and tracking of space debris. Moreover, the response of detectors under development could be tested directly on meteor events and with similar data collected by PRISMA cameras.
    
    

  Examples of Topics suitable for a Degree Thesis (Undergraduate and/or Postgraduate)

  • Topics for undergraduate or graduate thesis are available on the science projects described above. In the following a general idea of the topics will be reported. However, as the projects evolve rapidly, it's better to contact me directly to have the most updated information about possibilities. Periodically topics for thesis will be posted on the capmpusnet webage. In case of undergraduate thesis, it will be possible to combine it with a stage/traineeship either in Italy, or abroad within the Erasmus Traineeship program.
    At the following link it is possible to find a list of topics assigned to students in the past years and relative presentations.
    
    
    

    • Pierre Auger Observatory:

      The topics for thesis in the framework of the Pierre Auger Observatory are mainly related to the study of the energy spectrum, arrival direction and composition of cosmic rays, either in the transition region between galactic and extra-galactic origin, or at extreme energies. The study of the arrival directions of cosmic rays at the extreme energies is particularly important for astrophysics, as these events could reveal the astrophysical sources which have generated them. In fact, it is believed that if the primaries have a light nature (i.e. protons) they will be subject only to minor deflections from the magnetic fields. In this sense, energy, arrival direction and composition are the three key parametes to perform astronomy by means of charged particles. Typically the thesis are related to data analsyis and/or simulations, however, it doesn't exclude the possibility of performing hardware-oriented thesis related to the upgrade of the Auger project.
      
      

    • JEM-EUSO Program:

      The JEM-EUSO program allows to perform thesis within a extremely wide physics panorama, sometimes in a multi-disciplinary way as it is possible to focus on aspects related to cosmic ray science, astrophysics, physics of fundamental interactions, neutrino physics, dark matter, planetology, space weather, advanced technologies, electronics, informatics, atmospheric science, physics of complex systems, oceanography, bio-physics. The reason is that the innstrument is a telescope which studies the Universe by watching the Earth and its atmosphere. The detector has a spatial resolution tipically between 100 m and 6 km with a time resolution variable between microseconds and seconds. Therefore, it is possible to follow luminous phenomena occurring on different time scales with the only common condition of emitting light between 300 and 500 nm. Thanks to the ample spectrum of missions in data taking, data analysis or in the development and design phase, it is possible to have topics either of data analysis, or simulation, or hardware oriented with laboratory measurements (i.e. at TurLab).
      Depending on the topic chosen by the student, the thesis work could be performed in collaboration with other Professors or Researchers either of the Physics Department or of research centers such as INFN, INAF, ARPA Piemonte, Thales Alenia Space. Due to my role of Global Analysis Coordinator of the JEM-EUSO program, I have the duty of following the work performed also by the other groups of this international collaboration. Therefore, it will be possible to perform thesis activities in contact with researchers and students of all over the world, and in some cases to perform at least part of the work abroad within the Erasmus programs or with project funds.
      In the following I will report exemples of thesis projects to give an idea of the multiple possibilities offered by the project. Concerning cosmic ray physics it is possible to perform data analysis of EUSO-TA, EUSO-Balloon, EUSO-SPB and TUS missions to search for cosmic ray events, study of cosmic rays directly impacting in the detector, exposure estimation, study of the detector performance (this can be applied to all the detectors of the JEM-EUSO program). As the study of cosmic rays requires simulations of EAS generated by the primary particle interacting in the atmosphere, space detectors such as JEM-EUSO offer the opportunity of studying the longitudinal development of EAS cascades in the high atmosphere, and almost horizontal, which is a category of events which can not be studied by ground arrays. Their study allows to verify the models describing hadronic interactions in a contest and at energies which differ from those obtainables at accelerators. In this case it is possible to compare the characteristics of the observed events with the simulations foreseen by codes such as CORSIKA. Regarding neutrino physics it is possible to study the performance of EUSO-SPB2 and POEMMA concerning the observation of EAS geneated by tau neutrinos in atmosphere in case of earth-skimming neutrinos. For what concerns the topic of strange quark matter and dark matter, it is possible to analyze TUS data with the aim of looking for nuclearties. From the observational point of view, their closer companions are the meteors, which, however, have a different profile and angular velocity. Regarding planetology it is possible to study the meteor events collected by TUS and EUSO-TA to estimate magnitude and flux. More in general, it is possible to determine the expected flux of meteor and nuclearite events for Mini-EUSO, K-EUSO and POEMMA. This study is not only important from the planetological point of view, but also for what concerns the space defense, which means all the monitoring systems devoted to avoid or alert about catastrophic events such as in the case of Chelyabinsk fireball. Detectors such as TUS or the forthcoming Mini-EUSO mission could be used to test the possibility of detecting space debris. In this sense they will represent the first tests to verify the observational principle of such objects by means of detectors used in astro-particle science. The cloud coverage is another fundamental aspect to detect cosmic rays and to study the exposure. It is, therefore, extremely important to know the atmospheric conditions during the flight to know as a function of space and time if the sky was free for EAS observation. Moreover, in case of observed candidates it is important to know at best the atmospheric conditions to estimate properly the energy of the event. For this reason it is fundamental to use satellite data and models for weather forecasting. Moreover, as the detectors of the JEM-EUSO program have a very high spatial and temporal resolution, it is possible to verify the possibility of recognizing in the UV band the presence of clouds and their tipology. If this capability would be proven (current indications seem positive), JEM-EUSO detectors could help the sensors more commonly used for the observation of the atmosphere. JEM-EUSO sensors can detect also lightning of different nature with specific interest for the so called TLEs (elves, blue jets, sprites, etc.) whose origin and space-time characteristics are not fully understood. JEM-EUSO detectors monitor continuously the so called nightglow, which is the sky luminosity reflected by the atmosphere and by the ground, as well as the the light emitted by the airglow layer located at 100 km altitude. The light intensity is variable in space and time and can be associated to variations which have a solar origin, or they can be due also to planetary gravity waves or as a consequence of events such as tsunami. Therefore, the monitoring of the UV emission is important from one side to understand its origin, but on the other hand it helps to study phenomena related to space weather or for catastophic events such as tsunami. In clear atmospheric conditions stratospheric balloons and satellites can observe sea conditions. A possible applications, which require confirmation, is the possibility to observe phenomena of white capping and ocean waves in order to be, like for the atmospheric case, a new type of sensor working together with more traditional methodologies. EUSO-SPB data offer in principle the first possibility to explore this topic. JEM-EUSO detectors will be used also for problems related to bio-physics. Some types of plankton and seaweed emit in the near UV, therefore, JEM-EUSO could detect such emission. The study and monitoring of such systems is important to understand ocean conditions, as well as for more practical aspects such as fishing or marine pollution. The vast majority of the phenomena mentioned above require the use of analysis techniques used in the framework of the complex physics systems due to the complexity of phenomena which interplay. The search for cosmic ray events in the sea of nightglow background fluctuations and other type of phenomena require the application of sophisticated techniques such as machine learning as well as the use of big data. The software codes for simulation and data analysis are based on two big frameworks called ESAF and OffLine, therefore, they are very interesting bench tests for students who want to improve their data computing skills. They can develop and acquire competences in data mining by using quite complex software architectures. The sensors and the electronics used in JEM-EUSO are advanced technology. They need to work in challenging conditions being low-power consuming, radiation hard, insensitive to thermal excursions. In Torino we are in charge of developing the trigger logic to detect the different luminous phenomena that JEM-EUSO would like to observe. Those algorithms are implemented on FPGA. Their validation is performed by means of different methodologies: simulations, analysis of data collected by the missions which have been already operated, and experiments at TurLab (the fluidodynamics facility located at the fourth floor underground of the Physics Department). Moreover, all the possible upgrades of the optical system and sensors have to be validated in termis of detector performance, specifically for the physics of the mission. This is done by means of dedicated simulations.
      Due to the multi-disciplinary characteristics of the research items associated to the project, from one side it will be necessary to discuss with and get support from other research institutions. On the other hand, being JEM-EUSO an international collaboration, in case of master thesis it might be required, upon funds availability, to visit other institutions in Italy, Europe (Germany, France, Spain, Slovak Republic, Sweden), Japan (Tokyo, Kobe), US (Chicago, Colorado, Utah), Russia (Moscow) for data analysis, simulations, measurements or participation to collaboration meetings.
      
      

    • Extreme Energy Events:

      The EEE project gives the opportunity to perform a work in direct contact with a detector and more in general with an apparatus for cosmic rays. From the experimental point of view it will be possible to study the detector response as a function of atmospheric parameters such as pressure and temperature, as well as study the accuracy and precision in the track reconstruction. The detecotr will become part of the EEE network, therefore, it will be possible to perform coincidence analysis among the events detected by this station with those detected by other stations in Torino and in Italy to study cosmic ray events. The muon flux depends on solar activity, tehrefore, it will be possible to study Forbush decrease events and other type of solar phenomena. The EAS array on the roof of the building will be operated in coincidence with the EEE station to record at the same time the electromagnetic and muon components of the shower. This is a parameter of fundamental importance to distinguish muon events from EAS events especially when the correlation with other stations in Torino is performed. The use of the station in a stand alone mode or in correlation with the array on the roof will allow to prepare experiments suitable for teaching purposes at university or high school level. Moreover, it will possible to follow the work performed by the students of the Gobetti-Segre` high school as well as of other schools with the so called School-Work Alternation program. This kind of activity is highly recommended for students who want in perspective to teach physics at school.
      
      

    • PRISMA Project:

      Within the PRISMA project it will be possible to participate to the analysis of the fireball and bright meteorite data collected by the network. PRISMA data could be used also in correlation with those collected on common events by TUS and Mini-EUSO. As schools will be involved in an educational program, it will be possible to define a thesis project more suitable for teaching.
      
      

    • Space Debris Project:

      The thesis topics related to the Space Debris project will be devoted from one side to the development and test of an experimental apparatus correlated or uncorrelated with the PRISMA one, to understand the performance of such approach for space debris detection. An independent trigger seup will be required. Measurements will be performed at the Pino Torinese Observatory and Aosta Valley Observatories, as well as with tests at the TurLab facility. In parallel, or independently, we will use the ESAF software to study the limit in the observable magnitudes of a simple apparatus consisting of Fresnel lenses and a focal surface equipped with photo-multipliers or SiPMTs. The work will be carried out in contact with the researchers of the Thales Alenia Space Company.

  Stages in Italy and abroad

  • Depending on the thesis topic, the work might require part of the activity at the National Institute of Nuclear Physics in Torino, or the National Astrophysics Observatory of Torino (INAF), or at the Regional Environmental Protection Agency (ARPA Piemonte), which in case of bachelor students might be part of a stage project. It will be possible to perform part of the thesis or stage abroad within the Erasmus programs. In the past about twenty students in total have performed stages or thesis periods abroad at the following places: Institut de Recherche en Astrophysique et Planetologie (IRAP) of Touluse and Laboratoire de Astroparticule et Cosmologie of Paris-Diderot University (France); Universidad Carlos III de Madrid (Spain); Royal Institute of Technology in Stockholm (Sweden); Karlsruhe Institute of Technology (Germany); Slovak Academy of Sciences in Kosice (Slovak Republic).
    
    
    

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    [Universita' di Torino] [Facolta' di Scienze M.F.N.] [Corso di Studi in Fisica]
    [Dip.to di Fisica XXX] [I.N.F.N. Sez. di Torino]

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    Last modifications: 24 December 2017.