24 research outputs found
Muon Radiography Investigations in Boreholes with a Newly Designed Cylindrical Detector
Muons are constantly produced in cosmic-rays and reach the Earth surface with a flux of about 160 particles per second per square meter. The abundance of muons with respect to other cosmic particles and their capability to cross dense materials with low absorption rate allow them to be exploited for large scale geological or human-made object imaging. Muon radiography is based on similar principles as X-ray radiography, measuring the surviving rate of muons escaping the target and relating it to the mass distribution inside the object. In the course of decades, after the first application in 1955, the methodology has been applied in several different fields. Muography allows us to measure the internal density distribution of the investigated object, or to simply highlight the presence of void regions by observing any excess of muons. Most of these applications require the detector to be installed below the rock being probed. In case that possible installation sites are not easily accessible by people, common instrumentation cannot be installed. A novel borehole cylindrical detector for muon radiography has been recently developed to deal with these conditions. It has been realized with a cylindrical geometry to fit typical borehole dimensions. Its design maximizes the geometrical acceptance, minimizing the dead spaces by the use of arc-shaped scintillators. The details of the construction and preliminary results of the first usage are described in this paper
Muon radiography applications: the study of the Mt. Vesuvius Great Cone and the search and 3D modeling of underground cavities
Muon radiography, or muography, allows to investigate the internal structure of large dimensions objects such as volcanoes, pyramids, little hills, etcetera. It exploits muons produced in cosmic-rays, a natural source of particles constanly reaching the Earth's atmosphere from every directions. The very high penetrating power of muons makes them suitable for large bodies investigations. Muography have been successfully applied in different fields, ranging from volcanology to archaeology, civil engineering and much more. The goal of the technique is to assess the mass distribution inside the target, or the presence of voids or high-density anomalies. This thesis concerns different muon radiography applications partecipated by the author: the MURAVES experiment, devoted to the study of the Great Cone of Mt. Vesuvius, the search for underground cavity within the Mu-Ray project, and the development of a new borehole cylindrical detector for muongraphy applications
Detection and 3D Reconstruction of Cavities Inside Mount Echia, Naples, Italy
One of the potentialities of muonic radiography consists of the possibility of detecting cavities and reconstructing their shape in 3D, thus giving indications on their position and size. This new methodology can complement the traditional methods of cavity detection (georadar, gravimetry, geoelectrical, etc.) or be used when the latter cannot. We will present the methodology and show the results of a series of measurements carried out at Mount Echia. Mount Echia is a rocky hill in the center of Naples, inhabited since the antiquity. Over the course of history, a large number of cavities has been excavated for various purposes. Data were taken from three different positions inside Mount Echia, profiting from the complex system of tunnels and cavities. The validity of the method was demonstrated by the observation of known cavities through data analysis. Furthermore, an unknown cavity was identified and reconstructed in space. From the information thus obtained on the position of the cavity, it was possible to carry out a new inspection that supports the presence of the cavity
Muography of the Volcanic Structure of the Summit of Vesuvius, Italy
In the context of recent developments in volcanic muography, we describe an experiment at Vesuvius, the volcano near Naples that destroyed Pompeii and Herculaneum (Italy) in 79 CE. This volcano is about 1,200 m high with a typical summit caldera formed by Mount Somma. Vesuvius is among the highest-risk volcanoes in the world due to its highly explosive eruptive style and the high population density of the area where it is located. Volcanoes are generally fragile geological structures, prone to produce partial collapse and large landslides that can affect the style of eruptions. Moreover, the knowledge of the internal structure is fundamental for understanding past eruption activity and for constraining eruption models. For these reasons, studying the internal structure of the âGran Conoâ (great cone) of Vesuvius and the physical characteristics of its rock is important and led us to design a muography experiment at Vesuvius. This experiment, which is currently in progress, is based on three scintillator detectors with a surface of 1 m 2 each. These detector features have been implemented to overcome the problems related to the large thickness of rock that form the âGran Conoâ of Vesuvius and the effects that can be a source of error in data processing. These aspects represent an open challenge for the muography of large volcanoes, which today constitutes the frontier of research in the field of volcanic muography
Search for dark photon decays to at NA62
International audienceThe NA62 experiment at CERN, designed to study the ultra-rare decay , has also collected data in beam-dump mode. In this configuration, dark photons may be produced by protons dumped on an absorber and reach a decay volume beginning 80 m downstream. A search for dark photons decaying in flight to pairs is reported, based on a sample of protons on dump collected in 2021. No evidence for a dark photon signal is observed. A region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon masses between 215 and 550 MeV
Search for leptonic decays of the dark photon at NA62
International audienceThe NA62 experiment at CERN, configured in beam-dump mode, has searched for dark photon decays in flight to electron-positron pairs using a sample of protons on dump collected in 2021. No evidence for a dark photon signal is observed. The combined result for dark photon searches in lepton-antilepton final states is presented and a region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon mass values between 50 and 600 MeV and coupling values in the range to . An interpretation of the search result in terms of the emission and decay of an axion-like particle is also presented
Search for leptonic decays of the dark photon at NA62
The NA62 experiment at CERN, configured in beam-dump mode, has searched for dark photon decays in flight to electron-positron pairs using a sample of protons on dump collected in 2021. No evidence for a dark photon signal is observed. The combined result for dark photon searches in lepton-antilepton final states is presented and a region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon mass values between 50 and 600 MeV/ and coupling values in the range to . An interpretation of the search result in terms of the emission and decay of an axion-like particle is also presented.The NA62 experiment at CERN, configured in beam-dump mode, has searched for dark photon decays in flight to electron-positron pairs using a sample of protons on dump collected in 2021. No evidence for a dark photon signal is observed. The combined result for dark photon searches in lepton-antilepton final states is presented and a region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon mass values between 50 and 600 MeV and coupling values in the range to . An interpretation of the search result in terms of the emission and decay of an axion-like particle is also presented
Search for leptonic decays of the dark photon at NA62
International audienceThe NA62 experiment at CERN, configured in beam-dump mode, has searched for dark photon decays in flight to electron-positron pairs using a sample of protons on dump collected in 2021. No evidence for a dark photon signal is observed. The combined result for dark photon searches in lepton-antilepton final states is presented and a region of the parameter space is excluded at 90% CL, improving on previous experimental limits for dark photon mass values between 50 and 600 MeV and coupling values in the range to . An interpretation of the search result in terms of the emission and decay of an axion-like particle is also presented
Development of a new CEDAR for kaon identification at the NA62 experiment at CERN
International audienceThe NA62 experiment at CERN utilises a differential Cherenkov counter with achromatic ring focus (CEDAR) for tagging kaons within an unseparated monochromatic beam of charged hadrons. The CEDAR-H detector was developed to minimise the amount of material in the path of the beam by using hydrogen gas as the radiator medium. The detector was shown to satisfy the kaon tagging requirements in a test-beam before installation and commissioning at the experiment. The CEDAR-H performance was measured using NA62 data collected in 2023