[en] In 1981, a measurement of the flux of antiprotons (bar p's) in the cosmic radiation using a calorimetric detection method reported the ratio bar p/p as (2.2 ± 0.6) x 10^-4 for kinetic energies (at the top of the atmosphere) below 320 MeV; the result was two orders of magnitude higher than that predicted by conventional cosmic ray models. Many novel and interesting mechanism were proposed to explain the discrepancy; to fully resolve this problem, new experiments were needed. This thesis describes the balloon-borne detector PBAR, a magnetic spectrometer designed to identify and determine the energies of antiprotons and protons in the kinetics energy range 100-1500 MeV, and discusses the results from the successful 14-hour flight of August, 1987. PBAR, unlike previously flown spectrometers, determines directly the masses of cosmic rays by simultaneously measuring momentum and velocity. No bar p's were observed, and an upper limit of bar p/p < 4.6 x 10^-5 (1 σ level) for bar p kinetic energies less than 640 MeV has been reported. Further analysis by the author, with improved statistics and inclusion of data at higher energies, has yielded upper limits of 3.4 x 10^-5 for energies less than 640 MeV and 7.7 x 10^-5 for the energy range 640-1600 MeV. The PBAR results directly contradict the previous low energy measurement and are consistent with conventional models. After discussion of the previous experiments and motivation for a new measurement, a description of the instrument and each detector is given; a discussion is then made of the flight data and results. 2 refs

[en] A previous experiment measures an unexplaining large abundance of low-energy (0.1-0.3 GeV) cosmic-ray antiprotons, leading to suggestions that these might be annihilation products of a heavy, weakly-interacting dark matter component in the Galactic halo, such as photinos. The authors describe a new experiment that will measure the spectrum of cosmic ray antiprotons in the interval 0.1-1.5 GeV, and that will be sensitive to the distinct spectral signatures of processes such as γ/sup --/γ/sup --/ annihilation

[en] Production models were developed and the confirmation of each one had significant astrophysical impact. These include radical modifications of propagation models, cosmic ray antiprotons injection from neighboring domains of antimatter, p production by evaporating primordial black holes, and cosmic ray p's as annihilation products of supersymmetry particles that might make up the dark dynamical mass of the Galaxy. It is that p's originating from supersymmetric parents might have distinct spectral features that would survive solar modulation; in one model, higgsino annihilation proceeds through the bb quark-antiquark channel, producing a spectral bump at approx. 0.3 GeV in the p spectrum

[en] At the AMANDA South Pole site, four new holes were drilled to depths 2050 m to 2180 m and instrumented with 86 photomultipliers (PMTs) at depths 1520-2000 m. Of these PMTs 79 are working, with 4-ns timing resolution and noise rates 300 to 600 Hz. Various diagnostic devices were deployed and are working. An observed factor 60 increase in scattering length and a sharpening of the distribution of arrival times of laser pulses relative to measurements at 800-1000 m showed that bubbles are absent below 1500 m. Absorption lengths are 100 to 150 m at wavelengths in the blue and UV to 337 nm. Muon coincidences are seen between the SPASE air shower array and the AMANDA PMTs at 800-1000 m and 1500-1900 m. The muon track rate is 30 Hz for 8-fold triggers and 10 Hz for 10-fold triggers. The present array is the nucleus for a future expanded array. (orig.)

[en] We describe the PBAR balloon-borne magnet spectrometer flown on August 13-14, 1987 to measure the abundance of cosmic ray antiprotons in the energy interval 100-1580 MeV at the top of the atmosphere. The limits first reported have been improved to an overall limit of anti p/p<2.0x10^-5 (85% CL). We summarize the overall design and performance of the PBAR spectrometer, which had the unique ability to establish the mass of each singly charged cosmic ray, as well as to reject spurious antimatter candidates caused by hard scatterings within the instrument. (orig.)

[en] Enormous detectors with unprecedented sensitivity will be required to search for astrophysical sources of neutrinos. If the transparency of deep polar ice is similar to that measured in the laboratory, then AMANDA (Antarctic Muon And Neutrino Detector Array) may be the most cost-effective way to reach the detector volumes required to search for astrophysical sources of high energy neutrinos or WIMP annihilation within the sun. We describe a series of tests that will be conducted near the South Pole Station during the '91-'92 Antarctic campaign. The primary goal of these tests is to extend the optical transparency measurements of polar ice to a depth of one kilometer by measuring the rate of downward-moving muons with a prototype string of 4 optical modules. Additional objectives include the measurement of up/down discrimination, background light levels, and timing resolution. the design of the prototype string and its expected performance based on laboratory calibrations are discussed. (orig.)

[en] The HEAT (high-energy antimatter telescope) instrument has been developed for a series of observations in cosmic-ray astrophysics that require the use of a superconducting magnet spectrometer. This paper describes the first configuration of HEAT which is optimized for the detection of cosmic-ray electrons and positrons below 100 GeV. In addition to the spectrometer, a combination of time-of-flight scintillators, a transition radiation detector, and an electromagnetic shower counter, provides particle identification, energy measurement, and powerful discrimination against the large background of protons. The instrument was successfully flown aboard high-altitude balloons in 1994 and 1995. The design and construction of the spectrometer and of the detector systems are described, and the performance of the instrument is demonstrated with data obtained in flight. (orig.)

[en] The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10⁶ times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 x 10⁹ cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90 percent of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope