Abstract: The replacement of the H16-IN5 guide has been decided in the frame of the ILL Endurance program. This guide is made of heteroclite sections and the upgrade aims at improving the performances with a modern homogeneous ballistic guide. Several constraints applied to the project: (i) the instrument will remain at the same location, (ii) considering (i), in terms of gain relative to cost, it was judged more reasonable to keep the same chopper system, (iii) many technical elements under control of the nuclear safety authorities cannot be changed within the lifetime of the project. We present the results of the McStas optimization of the replacing guide performed under these constraints.
