INFN Sezione di Roma 2
Universita'  di Roma Tor Vergata"

Welcome to the  CAPRICE Homepage

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  NASA Movie  of a balloon launch (35Mb)

   The CAPRICE balloon and gondola just before take off.

The Cosmic AntiParticle Ring Imaging Cherenkov Experiment (CAPRICE) flew  for the first time in a balloon at 38 km altitude for 27 hours in  August 1994 (CAPRICE94). It collected data about more than 6 million cosmic  ray particles and the analysis to measure the amount of antimatter in the  cosmic radiation is well under way [see the web site for references and  publications]. The main aim of the experiment is to measure the flux of  antiparticles (antiprotons and positrons) in the cosmic radiation. The result will give valuable information on the production and transport of  cosmic rays in our galaxy. In addition one might find exotic sources of   antimatter, others than the expected secondary production from cosmic ray  nucleon interaction with the interstellar gas. Any excess of antimatter can come from annihilation of dark matter particles, extragalactic origin, evaporation of primordial black holes etc. We also continue the search for  heavier antinuclei (antihelium, anticarbon etc.) which would be a direct  evidence for the existence of anti-stars. The flux of all light isotopes  in the cosmic radiation gives valuable information about the production and transportation mechanisms of cosmic rays in our galaxy. Besides the RICH detector the spectrometer includes a super conducting magnet with a tracking detector system of drift chamber and multiproportional chambers, a time-of-flight system and an Si-W imaging  calorimeter. The CAPRICE97 experiment was successfully launched on the morning of 24 May1997. All instruments worked well and muon data were recorded during the three hour long ascent to a float altitude of 36 km. The flight  had to be terminated after four hours due to pressure problems.
CAPRICE98 was launched by balloon from Fort Sumner, New Mexico, on 1998 May 2. It floated at an atmospheric depth of about 5.5 g cm-2   for a period of 21 hr at a mean vertical cutoff rigidity of about 4.5 GV. More than 5 million triggers were collected at float altitude. A total of 31 antiprotons with a rigidity at the spectrometer between 4 and 50 GV were identified with small backgrounds from other particles. The absolute antiproton energy spectrum was determined in the energy region at the top of the atmosphere between 3.2 and 49.1 GeV. We found that the observed antiproton spectrum and the antiproton to proton ratio are consistent with a pure secondary origin. However, a primary component cannot be excluded.This experiment has reported the first mass-resolved high-energy antiprotons ever detected.
CAPRICE is one of the flights performed by the WiZard collaboration with members from France, Germany, Italy, Sweden and USA.

              Schematic view of the CAPRICE98 apparatus.



Page creator & mantainer: Aldo Morselli .
last update 20/1/01