Performance of the BACCUS transition radiation detector

Abstract

The Boron And Carbon Cosmic rays in the Upper Stratosphere (BACCUS) balloon-borne experiment flew for 30 days over Antarctica in December 2016. It is the successor of the CREAM balloon program in Antarctica which recorded a total cumulative exposure of 161 days. BAC-CUS is primarily aimed to measure cosmic-ray boron and carbon fluxes at the highest energies reachable with a balloon or satellite experiment, in order to provide essential information for a better understanding of cosmic-ray propagation in the Galaxy. The payload is made of multiple particle physics detectors which measure the charge up to Z=26 and energy of incident particles from a few hundred GeV to a few PeV. The newly designed Transition Radiation Detector (TRD) measures signals that are a function of the charge and Lorentz factor. In April 2016, BACCUS was taken to CERN in its flight configuration to characterize its detectors' response to beams of electrons and pions. The performance of the TRD using beam test data are reported in this paper.