One-dimensional (1D) spin chain is interesting to understand the low dimensional magnetism. For a 1D spin chain, long rang magnetic order cannot exists at finite temperature. On the other hand, the coupling between spin chains may govern the magnetic order although it is in general much weaker than intra-chain couplings. We had been given two days of beam time on MERLIN (RB1820213) to investigate magnetic excitations in Ba3CrS5 and Ba3CrSe5. Due to interesting dispersive excitations observed between 5 K and 300 K in Ba3CrS5 we spent two days of time on MERLIN for measuring temperature dependence of the excitations in Ba3CrS5. Here we propose to investigate magnetic excitations in Ba3CrSe5 using MERLIN and low energy excitations on OSIRIS to estimate the spin gap in Ba3CrS5 and Ba3CrSe5 to complete the study and obtain full understanding of the low-D magnetism of these compounds.