516 research outputs found

    A superconducting magnetic spectrometer for cosmic ray nuclei

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    Equipment specifications for balloon carried superconducting magnetic spectrometer to measure spectra of cosmic ray nuclei with charges ranging from protons to iro

    Calibration of a Stack of NaI Scintillators at the Berkeley Bevalac

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    A stack of twelve NaI (Tl) discs, 2 cm think each, has been exposed to sea level muons, and to beams of relativistic carbon, neon, argon, and manganese at the Berkeley Bevalac. For ^(55)Mn with γ = 2.75, the position-measuring accuracy of individual discs is better than ±2 mm, individual layer responses are close to the Landau distribution, and residual error for measuring total kinetic energy of the stopping ions is less than 0.25%

    Integrating Viral Hepatitis Screening and Prevention Services into an Urban Chemical Dependency Treatment Facility for American Indians and Alaska Natives

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    American Indian/Alaska Natives (AI/AN) patients at an urban residential chemical dependency treatment center participated in a viral hepatitis prevention project. Project activities integrated into patients’ treatment programs included viral hepatitis and human immunodeficiency virus (HIV) risk factor screening, education and counseling, laboratory testing, and hepatitis A and B vaccination. Of 928 AI/AN admissions, 585 (63%) completed risk factor screening assessment. Of these, 436 (75%) received at least one vaccination, viral hepatitis testing, or both. Of 322 patients tested, 91 (28%) were hepatitis C virus (HCV) antibody positive. Lack of pre-existing immunity to vaccine-preventable viral hepatitis infection was common: 132 (45%) were susceptible to hepatitis A and 224 (70%) were susceptible to hepatitis B infection. Chemical dependency treatment centers serving urban AI/AN provide important opportunities for implementing viral hepatitis prevention programs for high-risk populations and for improving ongoing efforts to reduce the disparate impact of chronic liver disease in AI/ AN people

    Initial results from the Caltech/DRSI balloon-borne isotope experiment

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    The Caltech/DSRI balloonborne High Energy Isotope Spectrometer Telescope (HEIST) was flown successfully from Palestine, Texas on 14 May, 1984. The experiment was designed to measure cosmic ray isotopic abundances from neon through iron, with incident particle energies from approx. 1.5 to 2.2 GeV/nucleon depending on the element. During approximately 38 hours at float altitude, 100,000 events were recorded with Z or = 6 and incident energies approx. 1.5 GeV/nucleon. We present results from the ongoing data analysis associated with both the preflight Bevalac calibration and the flight data

    A Cerenkov - ΔE/ΔX Experiment for Measuring Cosmic-Ray Isotopes from Neon Through Iron

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    A ballon-borne cosmic-ray experiment has been constructed to measure cosmic-ray isotope masses, It employs a pair of Cerenkov counters and a NaI scintillator stack to determine changes in ΔE in energy and Δγ in Lorentz factor for a traversing or stopping particle. Mass M = ΔE/Δγ. Mass resolution better than 0.3 a.m.u. is expected for incident elements from neon through iron, with incident Lorentz gammas ranging from 2.4 to 3.1, depending on the element. Using data obtained at the Berkeley Bevalac, the mass resolution ∂M ≈ 2 a.m.u., measured for ^(55)Mn ions with incident γ = 2.5

    Measurement of 0.25-3.2 GeV antiprotons in the cosmic radiation

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    The balloon-borne Isotope Matter-Antimatter Experiment (IMAX) was flown from Lynn Lake, Manitoba, Canada on 16–17 July 1992. Using velocity and magnetic rigidity to determine mass, we have directly measured the abundances of cosmic ray antiprotons and protons in the energy range from 0.25 to 3.2 GeV. Both the absolute flux of antiprotons and the antiproton/proton ratio are consistent with recent theoretical work in which antiprotons are produced as secondary products of cosmic ray interactions with the interstellar medium. This consistency implies a lower limit to the antiproton lifetime of ∼10 to the 7th yr

    Study of the April 20, 2007 CME-Comet Interaction Event with an MHD Model

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    This study examines the tail disconnection event on April 20, 2007 on comet 2P/Encke, caused by a coronal mass ejection (CME) at a heliocentric distance of 0.34 AU. During their interaction, both the CME and the comet are visible with high temporal and spatial resolution by the STEREO-A spacecraft. Previously, only current sheets or shocks have been accepted as possible reasons for comet tail disconnections, so it is puzzling that the CME caused this event. The MHD simulation presented in this work reproduces the interaction process and demonstrates how the CME triggered a tail disconnection in the April 20 event. It is found that the CME disturbs the comet with a combination of a 180∘180^\circ sudden rotation of the interplanetary magnetic field (IMF), followed by a 90∘90^\circ gradual rotation. Such an interpretation applies our understanding of solar wind-comet interactions to determine the \textit{in situ} IMF orientation of the CME encountering Encke.Comment: 13 pages, 3 figures, accepted by the ApJ Letter

    A Measurement of the Isotopic Composition of Cosmic Ray Iron

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    We present a new measurement of the isotopic composition of cosmic ray iron in the energy interval ~1550-2200 MeV /nucleon. The data were collected during the May 1984 flight of a balloon-borne spectrometer and show an average mass resolution of ~0.7 amu. The instrument employed the Cerenkov-Energy technique for mass determination. The observed ^(54)Fe/^(56)Fe ratio, 0.14 +0.18/-0.11 at the top of the atmosphere, is consistent with a solar system composition at the cosmic ray source. We also place an upper limit on the ^(58)Fe/^(56)Fe ratio at the top of the atmosphere of ≤.07. Both are consistent with previous measurements at lower energies
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