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A scientific experiment led by Rui Curado Silva, professor at the Faculty of Science and Technology of the University of Coimbra (FCTUC) and researcher at the Laboratory of Instrumentation and Experimental Particle Physics (LIP), goes into space on board the International Space Station through the European Space Agency (ESA).
The experiment, called “Aging of Ge/Si and CZT samples for sensors and Laue lenses”, includes researchers from the University of Beira Interior (UBI), from the Astrophysics and Space Sciences Observatory of Bologna, from the Institute National Astrophysics Institute of Italy (INAF/OAS-Bologna), and of the Institute of Materials for Electronics and Magnetism of the National Research Council of Parma (CNR/IMEM-Parma, Italy).
The experiment was selected as part of the “Euro Material Ageing” contest promoted by ESA and aims to analyze the effects of the space environment on the materials of the cameras of future gamma-ray telescopes.
Rui Curado Silva explains that “in order to observe the Universe at the wavelengths of X-rays and gamma rays, we are obliged to send telescopes equipped with sensors capable of capturing images of the sky in this spectrum band. electromagnetic. In effect, in this band of the spectrum, the atmosphere protects us and absorbs radiation before reaching the Earth’s surface”.
Coimbra scientists have developed new semiconductor sensors made of CZT (cadmium and zinc telluride) for the cameras of X-ray and gamma telescopes.
The problem, explains the coordinator of the space experiment, “is that when these sensors are exposed to the orbital radiation environment in space, they are damaged and their functioning degrades over time. Until today, these effects have never been studied with the required depth for this type of sensors”.
Therefore, some of these sensors will be sent into space, which will be installed on a platform that is outside the International Space Station (ISS: International Space Station).
This platform is called Bartolomeo and “it is exposed to the external radiation environment, as well as to extreme temperature variations: around -150°C when the ISS orbits on the night side of the Earth, and at temperatures around 120°C when the ISS is on the side of the sun”, says the FCTUC professor.
After a year of exposure to radiation and extreme cycles of temperature variation on the Bartolomeo platform – the duration of the mission, which should be launched between the end of 2021 and the middle of 2022 – “the CZT sensors will be used by us sent back to Coimbra. We will connect and test them to assess whether they are still operational and, if they work, how degraded they are,” he explains.
From this analysis, the team will then be able to validate or not these sensors to be used in future space telescopes for high energy astrophysics, as well as to understand how it will be possible to produce even better sensors.
“High energy astrophysics could benefit a lot from this technological development, in particular the understanding of the physics of the newly discovered gravitational waves, which are measured in terrestrial installations simultaneously with strong explosions of gamma rays that are measured in space by space telescopes. This simultaneous detection by two different messengers (gravity waves and gamma rays) is called multi-messenger astrophysics and is currently one of the most relevant topics in astrophysics”, concludes Rui Curado Silva.