Speaker
Description
The search for low-energy anti-nuclei in cosmic rays provides a means to test fundamental physics questions, such as the potential existence of primordial antimatter and the nature of Dark Matter.
The “PHeSCAMI” (Pressurized Helium Scintillating Calorimeter for AntiMatter Identification) project aims to explore a novel method for identifying anti-nuclei in cosmic rays. Specifically, when anti-protons or anti-deuterons come to rest in a medium, they can form exotic atoms. In the case of a helium target, the captured antiparticle can orbit the nucleus for microseconds before annihilating. This uniquely delayed annihilation serves as a clear signature to distinguish antimatter particles from ordinary cosmic rays.
A first prototype of the pressurized calorimeter—consisting of a 1L stainless steel vessel filled with helium at 200 bar—has been tested using cosmic muons and a 70–240 MeV proton beam at the INFN-TIFPA laboratory. Currently, development is underway for an advanced calorimeter prototype featuring a 40L volume, 200 bar pressure, and a wall grammage below 1.5 g/cm², utilizing an automotive composite overwrapped pressure vessel (COPV).
As part of the same project, an additional signature for anti-deuterons has been identified when the particle stops in plastic material. The annihilation with a hydrogen nucleus can lead to the emission of an anti-neutron, which subsequently annihilates after several nanoseconds, producing a distinctive double-annihilation signature in a segmented Time-of-Flight detector.
