Étude approfondie de la Division des sciences de la santé : rapport du Comité spécial d'étude du conseil

Version anglaise disponible dans la Bibliothèque numérique du CRDI: Health Sciences Division in-depth divisional review, 1987/88 : report of the Ad Hoc Board Review Pane

Search for point sources of neutrinos with KGF underground muon detectors

The proton decay detectors operated underground in the Kolar Gold Fields in India during 1980-1993 have recorded a large number of muon events. Out of these, 243 large zenith angle events were selected as being due to muons arising from neutrino interactions in the surrounding rock. This selection was based on the different zenith angular distributions of the atmospheric and neutrino-induced muons. These selected events are analysed here to look for powerful point sources of neutrinos

Health Sciences Division in-depth divisional review, 1987/88 : report of the Ad Hoc Board Review Panel

French version available in IDRC Digital Library: Etude approfondie de la Division des sciences de la santé : rapport du Comité spécial d'étude du consei

The design and use of plastic balloons for stratospheric research in India

"Plastic balloon flying has been developed at the Tata Institute of Fundamental Research as a research technique which has a number of important applications in India: (a) cosmic ray studies; (b) air sampling in the stratosphere for fall-out measurements; (c) meteorological investigations; (d) astronomical observations; (e) defence research. Comparatively little work has been done till now in these fields at equatorial latitudes, particularly at stratospheric altitudes. Large plastic balloons with volumes of the order of half a million cubic feet, and more, have been constructed by heat welding polyethylene sheeting 0.0015"" thick. With these balloons, successful level flights at altitudes of 110,000 ft. have been achieved; in some cases, individual loads weighing a hundred pounds have been carried up. The most serious problem encountered is the extremely low temperature(about-85DegreeC), of the tropopause at the equatorial latitudes; all known plastics for balloon manufacture become brittle at these low temperatures. To overcome this, dark fabrics have been employed so that the material is heated by solar radiation. The plastic sheeting employed is extruded in India to balloon specifications from chosen polymers. The low temperatures and the turbulent conditions that prevail in the atmosphere at low latitudes present problems in balloon flying which are different from those encountered at high latitudes present in balloon flying which are different from those encountered at high latitudes. The techniques employed, the design of the balloons, and their performance under these conditions are discussed.

The Kolar Gold Fields Neutrino Experimen. I. The Interactions of Cosmic Ray Neutrinos

Final results are presented of an experiment to study the interactions of cosmic ray neutrinos deep underground, at a depth of 7.6 ×105g cm-2 (standard rock). Clear examples have been recorded of neutrino-induced muons, including cases of upward moving particles and neutrino interactions within the detector assembly itself. The observed rate of events is compared with expectation and conclusions are made about the variation of the inelastic cross-section with energy and the lower limit to the mass of the intermediate boson. An examination has also been made of the celestial coordinates of the detected neutrinos and details are presented

The Kolar Gold Fields neutrino project.

In the underground laboratory at a depth of 7 600 ft in the Kolar Gold Mines, South India, five telescopes have been in operation for a study of the cosmic radiation which penetrates to such depths. In an exposure of 677 400 m2 sr h (for isotropic radiation) 46 events have been recorded. In seven events the particle trajectory has a projected zenith angle larger than 50°; these are interpreted as due to muons produced by neutrino interactions in the surrounding rock. From this the rate of neutrino-induced events is estimated to be about 3.1 × 10−13/cm2 s sr.The bulk of events with projected zenith angles less than 40° are interpreted as due to atmospheric muons, from considerations of the expected intensity and angular distribution. In between the above-mentioned two groups, there are 10 events in the zenith angle interval 40°–50° compared with an expected number of events of about two. The difference between the observed and expected rates in this angular interval is discussed.Recently, two new solid-iron magnet spectrographs have been installed at the same level, for measuring the momentum and sign of charge of the muons traversing the detector system. Each spectrograph has a maximum detectable momentum of 20 GeV/c and a collecting power of about 35 m2 sr for isotropic radiation