CaloCube: A new-concept calorimeter for the detection of high-energy cosmic rays in space

E Vannuccini,O Adriani,A Basti,S Bottai,A Rappoldi,N Finetti,M Bongi,N Zampa,A Tiberio,M Trimarchi,M Olmi,P Papini,S Detti,G Castellini,A Sulaj,O Starodubtsev,V Bonvicini,G Orzan,G Zampa,G Carotenuto,Federico Pirzio ,P Brogi,P S Marrocchesi ,A Tricomi,P W Cattaneo ,R D’alessandro ,P Maestro,M Miritello,L Bonechi,Lorenzo Pacini ,S Albergo,G Bigongiari,N Mori,M G Pellegriti ,П Спиллантини ,E Berti ,B Zerbo,Antonio Agnesi ,S Ricciarini,A Vedda,Francesco Stolzi ,L Auditore,A Trifirò ,Simone Bonechi ,P Lenzi,J E Suh ,M Fasoli

doi:10.1016/j.nima.2016.07.014

Abstract

The direct observation of high-energy cosmic rays, up to the PeV region, will increasingly rely on highly performing calorimeters, and the physics performance will be primarily determined by their geometrical acceptance and energy resolution. Thus, it is extremely important to optimize their geometrical design, granularity, and absorption depth, with respect to the total mass of the apparatus, which is among the most important constraints for a space mission. Calocube is a homogeneous calorimeter whose basic geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic scintillating crystals. This design forms the basis of a three-year R &D activity which has been approved and financed by INFN. A comparative study of different scintillating materials has been performed. Optimal values for the size of the crystals and spacing among them have been studied. Different geometries, besides the cubic one, and the possibility to implement dual-readout techniques have been investigated. A prototype, instrumented with CsI(Tl) cubic crystals, has been constructed and tested with particle beams. An overview of the obtained results will be presented and the perspectives for future space experiments will be discussed.

Highlights

IntroductionPrecise measurements of flux and composition of cosmic rays are needed to understand the mechanisms responsible for their production, acceleration and propagation
Precise measurements of flux and composition of cosmic rays are needed to understand the mechanisms responsible for their production, acceleration and propagation. These measurements can be performed directly in space or indirectly at ground. In the former case, the highest energy achievable is limited by the typical constraints in terms of mass (∼ 1 − 5 t) and life time (∼ 5 − 10 y) of a payload: being the cosmic rays flux very steep, it is difficult to collect enough statistics at high energy
It is possible to collect enough statistics up to the endpoint of the spectrum, but the properties of the cosmic rays must be reconstructed indirectly from the air showers detected at ground: because the hadronic interaction models used for this purpose have large systematics, these measurements of flux and, in particular, composition are affected by large uncertainties

Summary

Introduction

Precise measurements of flux and composition of cosmic rays are needed to understand the mechanisms responsible for their production, acceleration and propagation. These measurements can be performed directly in space or indirectly at ground In the former case, the highest energy achievable is limited by the typical constraints in terms of mass (∼ 1 − 5 t) and life time (∼ 5 − 10 y) of a payload: being the cosmic rays flux very steep, it is difficult to collect enough statistics at high energy (this is for example the case of protons above the knee region, located between 1015 and 1016 eV). Assuming 5 years of operations, they must have a good energy resolution σE/E (< 2% for electromagnetic showers, < 40% for hadronic showers) and a good effective geometric factor Geff 1 (> 3.5 m2sr for electromagnetic showers, > 2.5 m2sr for hadronic showers)

Objectives

Findings

Conclusion