Given the controversy about the magnetic ground state of the recently well studied triangular-lattice antiferromagnet (TLA) YbMgGaO4 due to Mg2+/Ga3+ disorder, we have synthesised a new TLA compound NdMgAl11O19 in which Nd3+ ions are arranged into perfect triangular lattice in the ab plane. Our previous polarised neutron diffraction and inelastic neutron scattering on powder samples have strongly indicated that this Ising-TLA material may be an ideal candidate to realise quantum spin liquid (QSL). We thus propose to carry out inelastic neutron scattering experiments on a co-aligned single-crystal sample (~2 g) at cold neutron chopper spectrometer LET, in order to study the low energy spin dynamic at the base temperature of a standard dilution refrigerator i.e. ~50 mK. We would request 7 days of beamtime at LET.