The CALOCUBE project for a space based cosmic ray experiment: design, construction, and first performance of a high granularity calorimeter prototype

TL;DR

The CALOCUBE project developed a compact, high-granularity calorimeter prototype for space-based cosmic ray detection, enabling more accurate measurements of cosmic ray spectra and composition at high energies.

Contribution

This work introduces a novel calorimeter design optimized for space missions, combining high granularity with low mass and volume, and reports on its construction and initial performance testing.

Findings

Successful construction of a large acceptance calorimeter prototype

Prototype demonstrated promising performance in particle beam tests

Design addresses space constraints while maintaining high detection capabilities

Abstract

Current research in High Energy Cosmic Ray Physics touches on fundamental questions regarding the origin of cosmic rays, their composition, the acceleration mechanisms, and their production. Unambiguous measurements of the energy spectra and of the composition of cosmic rays at the "knee" region could provide some of the answers to the above questions. So far only ground based observations, which rely on sophisticated models describing high energy interactions in the earth's atmosphere, have been possible due to the extremely low particle rates at these energies. A calorimetry based space experiment that could provide not only flux measurements but also energy spectra and particle identification, would certainly overcome some of the uncertainties of ground based experiments. Given the expected particle fluxes, a very large acceptance is needed to collect a sufficient quantity of data, in a time compatible with the duration of a space mission. This in turn, contrasts with the lightness and compactness requirements for space based experiments. We present a novel idea in calorimetry which addresses these issues whilst limiting the mass and volume of the detector. In this paper we report on a four year R&D program where we investigated materials, coatings, photo-sensors, Front End electronics, and mechanical structures with the aim of designing a high performance, high granularity calorimeter with the largest possible acceptance. Details are given of the design choices, component characterisation, and of the construction of a sizeable prototype (Calocube) which has been used in various tests with particle beams.