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Natural iron fertilization promotes the phytoplankton bloom that takes place on the Kerguelen Plateau in the Indian sector of the Southern Ocean. We measured 228 Ra (T 1/2 ¼ 5.75 yr) and 226 Ra (T 1/2 ¼ 1602 yr) in waters above the Kerguelen Plateau in order to provide information on the water-mass pathways, which in turn could help elucidate the mechanisms(More)
A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron(More)
Knowledge of the precise rigidity dependence of the helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. A precise measurement of the helium flux in primary cosmic rays with rigidity (momentum/charge) from 1.9 GV to 3 TV based on 50 million events is presented and compared to the proton flux. The detailed(More)
Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the(More)
This thesis involves three major projects: 1. Effects of bromination on the dc transport and magnetic properties of YBa 2 Cu 3 sO 7 , (YBCO) single crystals, 2. Power dependence of the microwave surface impedance of YBa 2 Cu 3 07-, thin films, and 3. Microwave properties of YBa 2 Cu 3 0 7-, Josephson junctions. In the first project, de-oxygenated(More)
A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} antiproton events and 2.42×10^{9} proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute(More)
  • Collaboration P L, Achard, O Adriani, M Aguilar-Benitez, M Van Den Akker Ag, J Alcaraz +418 others
  • 2004
The absolute muon flux between 20 and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 • to 58 •. Due to the large exposure of about 150 m 2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3% at 150 GeV in the vertical direction is achieved. The ratio of positive to negative(More)
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