F. Predieri

Study of penetrating cosmic ray muons and search for large scale anisotropies at the Gran Sasso Laboratory

Abstract The MACRO detector, located in the underground Gran Sasso Laboratory, had its initial data run from February 27 to May 30, 1989, using the first supermodule (SΩ∼800 m 2 sr ) . Approximately 245 000 muon events were recorded. Here are reported the results of the analysis of penetrating muons which determine the measured vertical muon flux at depths greater than 3000 m.w.e. In addition the data have been used to search for large scale anisotropies.

Fragmentation cross sections and search for nuclear fragments with fractional charge in relativistic heavy ion collisions

Abstract We present measurements of fragmentation cross sections of relativistic nuclei and upper limits for the production probability of nuclear fragments with fractional charge using CR39 nuclear track detectors and an automated scanning system. The measurements of the total and partial charge changing fragmentation cross sections concern 16 GeV/nucleon oxygen ions, 14.5 GeV/nucleon silicon ions and 200 GeV/nucleon sulphur ions interacting in copper and CR39 targets. No evidence for fractionally charged fragments was found requiring a minimum track length of 7 mm in CR39 detectors placed after a 14 mm copper target. The combined upper limit for the production probability of fractionally charged fragments relative to ordinary ones is at the level of 1.2–2.3 × 10–4 (90% C.L.). The charge resolution of the CR39 detectors for an average of 10 measurements of the same track is σ = 0.05e at Z = 6.

Bose-Einstein correlations in neutrino and antineutrino interactions in deuterium

Bose-Einstein correlations between pions of equal charge have been observed in Charged Current and Neutral Current (anti)neutrino-deuterium interactions in the BEBC bubble chamber exposed to the SPS wide band beam. The pion emission region is found to be essentially spherical with a mean radius of (0.48±0.07) fm; the chaoticity parameter is 0.36±0.04.

Calibration of the intercast CR39

Abstract We present new calibration results of the CR39 nuclear track detector made in collaboration with the Intercast Europe Co. of Parma, Italy. Upper limit on the production of nuclei with fractional charge has also been established. Results are also presented on the determination of the total and partial charge changing fragmentation cross sections of 28 Si 14+ ions of 14.5 GeV/nucleon and of 32 S 16+ ions of 200 GeV/nucleon in Copper targets.

Measurement of indoor radon levels in the Bologna metropolitan area

Abstract Indoor radon concentration in Bologna was monitored using two types of detectors with different characteristics. The measurements gave consistent results. It has been verified that the radon concentration in Bologna is well below the ‘attention’ level given in the scientific literature.

Status report of the macro experiment at gran sasso

Abstract The half of the MACRO detector, a large area Monopole, Astrophysics, Cosmic Ray Observatory is nearly completed in Hall B of the Gran Sasso Laboratory. One supermodule is already taken data and the remainder will be activated in few months. A general overview of the MACRO detector, together with its physics capabilities as far as the search for point sources of high energy neutrino is concerned, will be presented.