A computer program LEADS

written in about 6600 statements of MS FORTRAN 5.1 language

is suitable to run in IBM PC and other compatible computers. Program LEADS can make simulation for beam optical systems consisting of three-tube einzel lenses

three-aperture einzel lenses

two-tube lenses

uniform field DC accelerating tubes

magnetic and electrostatic quadrupoles

bending magnets

single-gap rf resonators

two-gap rf resonators （QWR） and three-gap rf resonators （SLR）.Multi-particle tracking and matrix multiplication are used to calculate the beam transport. Monte Carlo techniques are adopted to generate randomly the initial particle coordinates in the phase spaces

and Powell nonlinear optimization routines are incorporated in the codes to search the given optical conditions. The calculated results

can be displayed graphically on the computer monitors.