IN13 Neutron guide and primary spectrometer upgrade

We discuss the proposed upgrade of the IN13 neutron backscattering spectrometer at the Institut Laue-Langevin (Grenoble, France) and the resulting changes in instrument performance. The effect of using a temperature gradient monochromator on instrument flux and resolution is presented and reproduced using a multi-layer monochromator model for the Monte Carlo neutron ray tracing package McStas. Simulations of the combined effect of varying crystal mosaicity in conjunction with the gradient monochromator on supermirror guides are also shown.