Developments in the Electron Gun Simulation Program , EGUN

Technological progress in the performance of small computers has rapidly changed the demands on the software that is properly matched to the hardware. Table 1 shows running times on some PC-clones and workstations for the electron optics program EGN2 (1) running a simulation of a gun for an Electron Beani Ion Source (EBIS) (2). The speed increases shown in Table 1 have been accompanied by a reduction in memory cost that now permits from 8 to 32 Mbyte, or more of random access memory (RAM) in PCs. The challenge for the supplier of a simulation code such as EGN2, is to respond to the increasing computer capability, and increasingly challenging demands by users, in the way that best meets the needs of the community while preserving the investment in experience with the program. In this paper, we describe how EGN2 developed in response to these factors. The original PL-1 and Fortran versions of EGUN for mainframe computers have evolved into today’s family of programs including preprocessors, graphics programs, and post processors all working together in support of the C program EGN2 and the Fortran program IGUNe. This family tree is illustrated in Table 2.