Identification of positrons and electrons in the cosmic radiation with the electromagnetic calorimeter ECAL for the AMS-02 experiment

In May 2011 AMS-02 detector has been successfully installed on the International Space Station (ISS), where it will take data on cosmic radiation from 1 to 1000 GeV for at least 10 years. Among all scientific objectives of the experiment, one of the most important is the search for Dark Matter (DM), which constitutes ∼ 80% of the Universe mass, but its nature is still unknown. A DM signal can be identified by studying the combined fluxes of positrons, photons, antiprotons and antideuterium. Thanks to its high acceptance and its performances, AMS-02 detector can extend and expand primary cosmic ray physics search to a new energy range with high accuracy. A key role for these measurements, in particular for electromagnetic channels, is played by ECAL calorimeter. This subdetector has been developed to measure γ, e− and e+ energy with an accuracy of few %. Thanks to its 3D shower reconstruction imaging capabilities, it also has a high separation power between electromagnetic and hadronic showers (e/p rejection), essential to eliminate proton background (∼ 10^4 ) in positron channel. Finally, it provides the trigger on photons which do not interact in the upper part of the detector (about 72% of the ones in ECAL geometrical acceptance). In Chapter 1 of this thesis, cosmic ray physics is introduced with details on Big Bang cosmology and the DM problem. Then, a summary of direct and in particular indirect searches for DM signature is presented. In Chapter 2 and 3 AMS-02 detector is presented with an overview of each subdetector features and performances. ECAL electromagnetic calorimeter is described in detail. Chapter 4 describes an in-flight calibration method, which has been developed and tested on August 2010 Test Beam data, with its application performances on ground and on in-flight data. In Chapter 5, the calorimeter capabilities have been used to develop e± identification algorithms, using both ECAL standalone and also tracker momentum measurements. The definition of algorithms, training and testing processes, data-MC comparisons and proton rejection spectrum are described

Measurement of the cosmic (e+ + e-) flux from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer (AMS-02) on the International Space Station

The measurement of cosmic ray positrons and electrons (e+/-) provides fundamental information about the origin of cosmic rays, and may disclose evidence for Dark Matter activity in the Galaxy. In this thesis, the 10.6 million e+/- events collected by the AMS-02 detector on the International Space Station in the first 30 months of data taking have been used to measure the (e+ + e-) flux from 0.5 GeV to 1 TeV with unprecedented precision. No structures have been observed in the resulting flux

Measurement of the cosmic ray (e + +e ) flux with AMS

The cosmic ray (e + + e ) flux has been measured by the Alpha Magnetic Spectrometer (AMS-02) in the energy range 0.5 GeV to 1 TeV, based on the analysis of 10.6 million e events collected during the first 30 months of data taking. The statistics and the resolution of the AMS-02 detector provide an accurate measurement in the whole energy range. No features have been observed in the flux, and the (e + + e ) spectrum can be accurately described by a single power law above 30 GeV. The procedures and the data analysis techniques for the (e + + e ) flux measurement are reviewed in this report

Advantages and Requirements in Time Resolving Tracking for Astroparticle Experiments in Space

A large-area, solid-state detector with single-hit precision timing measurement will enable several breakthrough experimental advances for the direct measurement of particles in space. Silicon microstrip detectors are the most promising candidate technology to instrument the large areas of the next-generation astroparticle space borne detectors that could meet the limitations on power consumption required by operations in space. We overview the novel experimental opportunities that could be enabled by the introduction of the timing measurement, concurrent with the accurate spatial and charge measurement, in Silicon microstrip tracking detectors, and we discuss the technological solutions and their readiness to enable the operations of large-area Silicon microstrip timing detectors in space

The Gamma-Flash data acquisition system for observation of terrestrial gamma-ray flashes

Gamma-Flash is an Italian project funded by the Italian Space Agency (ASI) and led by the National Institute for Astrophysics (INAF), devoted to the observation and study of high-energy phenomena, such as terrestrial gamma-ray flashes and gamma-ray glows produced in the Earth's atmosphere during thunderstorms. The project's detectors and the data acquisition and control system (DACS) are placed at the "O. Vittori" observatory on the top of Mt. Cimone (Italy). Another payload will be placed on an aircraft for observations of thunderstorms in the air. This work presents the architecture of the data acquisition and control system and the data flow.Comment: 4 pages, 1 figure, Astronomical Data Analysis Software and System XXXII (2022

Dynamic and on demand data streams

Replicability and efficiency of data processing on the same data samples are a major challenge for the analysis of data produced by HEP experiments. High level data analyzed by end-users are typically produced as a subset of the whole experiment data sample to study interesting selection of data (streams). For standard applications, streams may be eventually copied from servers and analyzed on local computing centers or user machine clients. The creation of streams as copy of a subset of the original data results in redundant information stored in filesystems and may be not efficient: if the definition of streams changes, it may force a reprocessing of the low-level files with consequent impact on the data analysis efficiency. We propose an approach based on a database of lookup tables intended for dynamic and on-demand definition of data streams. This enables the end-users, as the data analysis strategy evolves, to explore different definitions of streams with minimal cost in computing resources. We also present a prototype demonstration application of this database for the analysis of the AMS-02 experiment data

Precision Measurement of the Positron Fraction in Primary Cosmic Rays with AMS on the Space Station

The AMS-02 experiment is a large acceptance spectrometer continuously operating onboard the International Space Station since May 2011. One of the main objectives of the AMS-02 mission is the measurement of the rare antimatter components of cosmic rays. In six years of operations, AMS-02 has detected 20 million cosmic ray electrons and positrons that have been used to precisely measure the positron fraction – the ratio of positrons over the sum of positrons and electrons – in cosmic rays from 0.5 GeV to 700 GeV. The analysis of the latest data collected by AMS-02 extends the energy range of the previous measurement and improves its precision.The AMS-02 experiment is a large acceptance spectrometer continuously operating onboard the International Space Station since May 2011. One of the main objectives of the AMS-02 mission is the measurement of the rare antimatter components of cosmic rays. In six years of operations, AMS-02 has detected $\sim$20 million cosmic ray electrons and positrons that have been used to precisely measure the positron fraction -- the ratio of positrons over the sum of positrons and electrons -- in cosmic rays from 0.5\,GeV to 700\,GeV. The analysis of the latest data collected by AMS-02 extends the energy range of the previous measurement and improves its precision

The Penetrating particle ANalyzer (PAN) instrument for measurements of low energy cosmic rays

PAN is an instrument designed to precisely measure and monitor the flux, composition, and direction of highly penetrating particles (>100MeV/nucleon) in deep space and interplanetary missions with an energy resolution better than 10% for nuclei from H to Fe at 1GeV/n. The detector, limited to about 20kg in mass and 20W in power consumption, is based on the well-known magnetic spectrometer detection principle, and exploits the advantages provided by the integration of ultra-thin microstrip silicon detectors, hybrid silicon pixel detectors and silicon photomultipliers. This novel layout and detection concept facilitates the flexibility of the PAN instrument for a variegate spectrum of space missions and applications, and opens the possibility to deploy PAN instruments over a distributed array monitoring the radiation environment in different positions of the heliosphere. PAN will measure the properties of cosmic rays in the 100MeV/n - 20GeV/n energy range in deep space with unprecedented accuracy, providing novel results to investigate the mechanisms of origin, acceleration and propagation of galactic cosmic rays and of solar energetic particles, and producing unique information for solar system exploration missions

Photodiode Read-Out System for the Calorimeter of the Herd Experiment

HERD is a future experiment for the direct detection of high energy cosmic rays. The instrument is based on a calorimeter optimized not only for a good energy resolution but also for a large acceptance. Each crystal composing the calorimeter is equipped with two read-out systems: one based on wavelength-shifting fibers and the other based on two photodiodes with different active areas assembled in a monolithic package. In this paper, we describe the photodiode read-out system, focusing on experimental requirements, design and estimated performances. Finally, we show how these features lead to the flight model project of the photodiode read-out system