Optimizing Monochromatic Focusing on ThALES

Neutron ray-tracing simulations have been done in order to study the interplay between an elliptically shaped guide end with two double focusing monochromators - pyrolytic graphite PG002 and bent Si111. The primary aim of these calculations has been the optimisation of the neutron optics of the new cold triple-axis spectrometer ThALES, the successor of the IN14 spectrometer at the Institut Laue-Langevin, Grenoble. The obtained results are, nevertheless, general and independent of the specific geometry of ThALES. The beam characteristics in terms of flux, real space and angular distribution and energy resolution at the sample position are presented for both cases