( 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A. PROPAGATION OF COSMIC-RAY NUCLEONS IN THE GALAXY

We describe a method for the numerical computation of the propagation of primary and secondary nucleons, primary electrons, and secondary positrons and electrons. Fragmentation and energy losses are computed using realistic distributions for the interstellar gas and radiation Ðelds, and di†usive reacceleration is also incorporated. The models are adjusted to agree with the observed cosmic-ray B/C and 10Be/9Be ratios. Models with di†usion and convection do not account well for the observed energy dependence of B/C, while models with reacceleration reproduce this easily. The height of the halo propagation region is determined using recent 10Be/9Be measurements as [4 kpc for di†usion/convection models and 4È12 kpc for reacceleration models. For convection models, we set an upper limit on the velocity gradient of dV /dz \ 7kms~1 kpc~1. The radial distribution of cosmic-ray sources required is broader than current estimates of the supernova remnant (SNR) distribution for all halo sizes. Full details of the numerical method used to solve the cosmic-ray propagation equation are given. Subject headings: acceleration of particles È cosmic rays È di†usion È Galaxy: general È ISM: abundances È ISM: general 1