  In this paper, we propose a collective Thomson scattering diagnostic for fast
ion measurements for the gas-dynamic trap (GDT) facility at the Budker
Institute. The diagnostic utilizes 54.5 GHz gyrotron usually used for electron
cyclotron resonance heating as a source of probe radiation and is aimed at
reconstruction of distributions over transverse and longitudinal velocities of
NBI-driven ions in the plasma core. Here we present a feasibility study of this
concept.
