Speakers
Description
The direct measurements of the antimatter components in cosmic rays provide a crucial information
on the mechanisms responsible for their acceleration/propagation and represent a powerful tool for
the indirect search of dark matter. At present, charge sign discrimination has been performed by the
use of magnetic spectrometers, which are not suited to extend the current measurements at higher
energies in a relatively short time scale. Since most of present and future experiments in space
dedicated to the high energy frontier are based on large size calorimeters, it would be important to
develop an alternative charge sign discrimination technique that can be integrated with them.
Investigating this technique is the main goal of the Electron Positron Space Instrument (EPSI)
project, an R&D that has been approved and financed in Italy as a PRIN (Research projects of
relevant national interest), whose activity started in September 2023. To this end, we plan to exploit
a principle that has been suggested long time ago, based on the synchrotron radiation emitted by
charged particles as they travel into the geomagnetic field. The simultaneous detection of a
electron/positron with an electromagnetic calorimeter and synchrotron photons with a X-ray
detector is enough to discriminate among the two leptons at the event level. The main challenge is
to develop a X-ray detection array with very large active area, high X-ray detection efficiency, low
energy detection threshold and compliant with space applications.
In order to achieve the required specifications while keeping the cost sufficiently low to equip a
large area, we investigate the feasibility to develop a single detection cell based on a small
scintillator, a large area SiPM and a thin aluminum layer deposition. Different solutions for the
components and the geometry of the detection cell are currently under test both with laboratory
measurements and detailed simulations. In this contribution, we will discuss the current status of the
R&D and next steps for the fulfillment of the project goals.
