Continued development of the next generation of SOURCES

In development for over two decades, the SOURCES computer code calculates neutron production rates and spectra from four types of problems: homogeneous media, two-region interfaces, three-region interfaces and that of a monoenergetic alpha particle beam incident on a slab of target material. In terms of file structure, SOURCES consists of a usercreated input file (tapel), several data files (tapes 2-5) and up to six output files (outp, outp2, and tapes 6-9). SOURCES was recently upgraded from version 4A to version 48 when the code's decay data library, tapeti, was updated for 44 of the 105 available decay sources. The new version provided spontaneous fission information for 252Cf and alpha decay data revisions for 43 isotopes and isomers having Watt fission spectra parameters.' Following that work, this summary documents similar modifications made to the remaining 61 sources. It also summarizes additional enhancements and planned improvements to SOURCES for the next major code release.