A groundbreaking discovery in the field of physics has been made by researchers at the Department of Physics and Geology in Perugia, Italy, in collaboration with the National Institute of Nuclear Physics (INFN). The team, part of the international AMS-02 collaboration, has achieved a first-of-its-kind observation: the temporal variation of antiprotons, helium, carbon, and oxygen over an entire solar cycle, spanning 11 years. This unprecedented achievement provides invaluable insights into the effects of solar activity.
The AMS-02 experiment, operating on the International Space Station since 2011, has amassed over 240 billion data points, meticulously identifying cosmic rays by type and energy, distinguishing matter from antimatter, and heavy nuclei from light nuclei. This international scientific initiative, involving researchers from various Italian universities and INFN sections, is supported by the Italian Space Agency (ASI).
The Perugia group played a pivotal role in the design and construction of AMS-02, continuing to support data acquisition, analysis, and the development of new detectors for enhanced performance. Their ongoing research, including tests at the SERMS space qualification laboratories in Terni, demonstrates their commitment to pushing the boundaries of space exploration.
The expertise gained through the AMS collaboration has equipped the Perugia team with valuable knowledge about the radiation environment in space. This knowledge will be further developed through a long-term agreement between the University of Perugia and ASI, as well as the "Department of Excellence" project, Space and Universe Perugia Research Cluster (SUPER-C), which has secured a €9 million investment from the Italian Ministry of University and Research (MUR) for the period 2023-2027.
"The AMS-02 data on the temporal variation of numerous cosmic ray species is a unique dataset that will allow us to study the propagation of cosmic rays in the heliosphere in detail," emphasizes Professor Bruna Bertucci, Vice-International Coordinator of the AMS collaboration. "The results obtained from the AMS-02 experiment are providing original and unexpected scientific findings on the origin and propagation of cosmic rays. Only a magnetic spectrometer operating in space, like AMS-02, can measure the sign of the charge of cosmic rays and thus obtain these results."
"We have shown that the variation in time is similar for particles with the same charge sign and markedly different for particles with opposite signs. Moreover, for the first time, we have observed that the intensity of the variation is different for nuclear species between helium and oxygen and is related to the spectral shape of the particle flux," comments Dr. Maura Graziani, researcher at the Department of Physics and Geology and local coordinator of the UniPg/INFN research group for the AMS experiment.
"Charged cosmic radiation represents one of the main risks for instrumentation and astronaut health in space," observes Professor Nicola Tomassetti, head of the radiation studies program within the UniPg-ASI agreement. "The data collected by the AMS-02 experiment are providing fundamental scientific results for the development of astronaut protection systems from the inevitable and continuous exposure to cosmic radiation in space."