High-energy deuteron measurement with the CAPRICE98 experiment

The CAPRICE98 balloon-borne instrument was flown on 28-29 May 1998 from Fort Sumner (New Mexico, USA). The detector configuration included the NMSU-WiZard/CAPRICE superconducting-magnet spectrometer equipped with a gas RICH, a silicon-tungsten calorimeter and a time-of-flight system. By combining the information from the spectrometer and the RICH, which was used as a threshold device, it was possible to separate H-2 from H-1 in the kinetic energy range from 12 to 22 GeV/n. In order to estimate the proton background and the deuteron selection efficiency, an empirical model for the response of the instrument, based on the data collected in this experiment, was developed. The analysis procedure is described in this paper and the results on the absolute flux of H-2 and H-2/He ratio are presented. These data on H-2 abundance represent the only measurements above 10 GeV/n.