TY - UNPB N2 - This thesis describes the construction of an atomic matter-wave interferometer, combined with a spin-state interferometer, used to weakly measure the average transverse momentum of the atoms. A velocity-tuneable cold atomic beam was constructed and characterised. By applying radiation pressure to a magneto-optical trap, the beam's velocity was selected between 1-52 ms-1. The beam was used to produce interference fringes in a matter-wave interferometer which consisted of a mutli-slit Si3Ni4 grating and a planar atom detector placed below the grating. The interference pattern was used to measure the average beam velocity and the Van der Waals coefficient between the atoms and the grating. This was the first instance of such a measurement. Below the grating a longitudinal Stern-Gerlach interferometer was constructed. The phase shift of the atom's spin, due to the Zeeman effect from the interferometer's magnetic field, was measured. The phase shift provided a measurement of the interferometer's magnetic field in the ?T range. An experiment combining the two interferometers to weakly measure the atom's transverse momentum is described and modelled. A1 - Morley, Joel EP - 169 AV - public UR - https://discovery.ucl.ac.uk/id/eprint/10115460/ Y1 - 2020/11/28/ ID - discovery10115460 N1 - Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author?s request. M1 - Doctoral TI - Towards a weak measurement of transverse momentum in a matter-wave interferometer PB - UCL (University College London) ER -