The Heusler alloys Ni-Mn-Ga are widely considered as a new generation of multifunctional smart materials due to the mutual interplay between structural and magnetic properties (magnetic shape memory effect). The observed properties are related to the martensitic transformation which retain the ferromagnetic state of the parent austenitic phase. The stoichiometric prototypical Ni2MnGa exhibits a martensitic transformation, taking place at Tm=220K, to an orthorhombic phase showing incommensurate modulation. The martensitic transition in Ni2MnGa can also be triggered by mechanical compression upon single crystals at RT. We applied for beamtime at WISH to perform a TOF diffraction experiment on the stress-induced martensitic transformation of a single crystal of Ni2MnGa. The key objective is the determination of the complex crystal structures of the phases stabilized under compression