  ISICS, originally a C language program for calculating K-, L- and M-shell
ionization and X-ray production cross sections from ECPSSR and PWBA theory, has
been reengineered into a C++ language class, named ISICSoo. The new software
design enables the use of ISICS functionality in other software systems. The
code, originally developed for Microsoft Windows operating systems, has been
ported to Linux and Mac OS platforms to facilitate its use in a wider
scientific environment. The reengineered software also includes some fixes to
the original implementation, which ensure more robust computational results and
a review of some physics parameters used in the computation. The paper
describes the software design and the modifications to the implementation with
respect to the previous version; it also documents the test process and
provides some indications about the software performance.
