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Abundance of the Radioactive Be-10 in the Cosmic Radiation up to 2 GeVnucleon-l with the Balloon-borne Instrument ISOMAX1998The Isotope Magnet Experiment (ISOMAX) a balloon-borne superconducting magnet spectrometer was designed to measure the isotopic composition of the light isotopes (3 less than or equal to Z less than or equal to 8) of the cosmic radiation up to 4 GeV nucleon (exp -1) with a mass resolution of better than 0.25 amu by using the velocity vs. rigidity technique. To achieve this stringent mass resolution ISOMAX was comprised of three major detector systems, a magnetic rigidity spectrometer with a precision drift chamber tracker in conjunction with a three-layer time-of-flight system and two silica-aerogel Cherenkov counters for the velocity determination. A special emphasis of the ISOMAX program was the accurate measurement of radioactive Be-10 with respect to its stable neighbor isotope Be-9, which provides important constraints on the age of cosmic rays in the Galaxy. ISOMAX had its first balloon flight on August 4-5, 1998, from Lynn Lake, Manitoba, Canada. Thirteen hours of data were recorded during this flight at a residual atmosphere of less than 5 g per square centimeter. The isotopic ratio at the top of the atmosphere for Be-10/Be-9 was measured to be 0.195 plus or minus 0.036 (statistical) plus or minus 0.039 (systematic) between 0.26 - 1.03GeV nucleon (exp -1) and 0.317 plus or minus 0.109 (statistical) plus or minus 0.042 (systematic) between 1.13 - 2.03GeV nucleon(exp -1). This is the first measurement of its kind above 1 GeV nucleon (exp -1). ISOMAX results tend to be higher than predictions from current propagation models.
Document ID
20040034754
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Hams, T.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Barbier, L. M.
(Siegen Univ. Germany)
Bremerich, M.
(Siegen Univ. Germany)
Christian, E. R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
deNolfo, G. A.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Geier, S.
(California Inst. of Tech. Pasadena, CA, United States)
Goebel, H.
(Siegen Univ. Germany)
Gupta, S. K.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hof, M.
(Siegen Univ. Germany)
Menn, W.
(Siegen Univ. Germany)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Space Radiation
Funding Number(s)
PROJECT: RTOP 353-87-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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