G.A. de Nolfo, A.J. Davis, A.W. Labrador, R.A. Mewaldt, S.M. Schindler
       California Institute of Technology, Pasadena, California, USA
L.M. Barbier, E.R. Christian, K.E. Krombel, J.W. Mitchell, J.F. Ormes, 
R.E. Streitmatter
       NASA Goddard Space Flight Center
O. Reimer 
       Max-Planck-Institut fuer extraterrestrische Physik
W. Menn, M. Hof, M. Simon
       Universitat Siegen
R.L. Golden, S.J. Stochaj, W.R. Webber
       New Mexico State University
I.L. Rassmussen
       Danish Space Research Institute

The rare isotopes of hydrogen and helium, ²He and ³He, in cosmic rays are believed to originate from the interaction of protons and helium within the galactic interstellar medium. The unique propagation history of these rare isotopes provides important constraints on galactic cosmic ray source spectra and propagation within the Galaxy. Hydrogen and helium isotopes were measured with the balloon-borne experiment, IMAX, which flew from Lynn Lake, Manitoba in 1992. The IMAX detector was designed to measure antiprotons and light isotopes using the combination of a super-conducting magnet spectrometer, aerogel cherenkov detectors, scintillation detectors, and a time of flight system. The energy spectrum of deuterium between 0.5 and 3.2 GeV/nucleon measured by the IMAX experiment as well as previously published results of ³He from the same instrument will be compared with predictions of cosmic ray galactic propagation models.