  We report on studies of the loss maps for particles travelling from the end
of the ThomX's linac along the transfer line to the end of the ring first turn
in preparation of the machine commissioning. ThomX is a 50-MeV-electron
accelerator prototype which will use Compton backscattering to generate a high
flux of hard X-rays. The accelerator tracking code MadX is used to simulate
electrons' propagation and compute losses. These maps may be projected at any
localisation along the bunch path or plotted along the bunch path. This
information is particularly relevant at the locations of the monitoring devices
(screens, position monitors,...) where loss predictions will be compared with
measurements.
