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Introduction
The Goddard ISOMAX experiment was a state-of-the art superconducting
magnetic mass spectrometer constructed for the purpose of measuring
the abundance of isotopes in the cosmic radiation. Cosmic radiation is the
term used for high energy particles coming from the Sun, the Galaxy, and
beyond.
This enabled the balloon-borne instrument, which was first
flown in August '98, to put constraints on the typical travel times of
cosmic rays and the density of the propagated medium -- hence on the
question how old cosmic rays really are and much time they
spend traveling outside the galactic disk.
Secondary nuclei in the cosmic radiation, which are produced in the
process of propagation and nuclear fragmentation of primary particles
through the interstellar medium, can be used to gain information on
the propagation mechanism, and the details of the cosmic ray diffusion
and the gas distribution in the galaxy.
If the production of isotopes in these fragmentation processes is
understood, then the measurement of the ratios of these isotopes as
they arrive on earth (especially ratios of the isotopes of Beryllium,
7Be, 9Be and the radioactive 10Be, which has a half-life of 1.6 Myrs) at
energies around 1GeV/nucleon can be used to decide between different models
of cosmic ray production and propagation.
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