The experimental goal of the ISOMAX experiment are measurements of light isotopes, especially the Be10/Be9 ratio, up to an energy of some GeV/n. Because of the small fluxes of Beryllium, ISOMAX has a large geometry factor of about 550 cmsr. The Balloon flights will be long-duration flights lasting several days. For this purpose low-power electronics were developed.
The ISOMAX magnet spectrometer consists of a superconducting double-coil magnet and high-resolution driftchambers.
The driftchambers use the same driftcell structure as the chambers used in the previous Balloon experiments. Ground myon tests showed a resolution of about 60-70 m. The expected resolution for higher charged particles is about 40-50 m.
With an average magnetic field of about 0.6 Tesla the MDR (Maximal Detectable Rigidity) of the spectrometer will be around 780 GV for single charged particles and more than 900 GV for Beryllium. Therefore the spectra of particles up to energies of about 1 TeV can be measured.
For particle identification a Time-Of-Flight counter similar to the IMAX experiment is used. The time-resolution for single-charged particles should be 120-130 ps, for Beryllium we expect around 60-80 ps.
To cover a higher energy range, an additional velocity measurement is added using aerogel cherenkov counters. The construction will be similar to the IMAX experiment.
Since the delivery of the magnet was delayed, we had to wait for the first flight from Lynn Lake, Manitoba until summer of 1998. ISOMAX was launched on august 4th at 11:58 Z, and landed on august 5th near Peace River/Alberta around 21:00 Z.

ISOMAX photo gallery


  • Goddard Space Flight Center
  • California Institute of Technology
  • Danish Space Research Institute

    ISOMAX Publications

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    Last updated 08/13/00 by T. Hams