An optically accessible pressure vessel and ancillary instrumentation for studies of diesel spray dynamics has been designed and built at the Australian Maritime College. The requirement for large observation windows and internal pressures up to 10MPa necessitated the use of finite element analysis in conjunction with first principles analysis. Strain gauge testing confirmed the calculated maximum stresses in the observation windows. The chamber is a registered pressure vessel conforming to AS 1210. A purpose built injection system capable of fuel pressures up to 120MPa and injection pulse durations up to 30ms has been implemented. Laser based instrumentation is synchronised with individual injection events to measure spray droplet velocities and sizes.