[en] When studying the interaction of short-lived particles with nuclei, a target of the highest possible density is advantageous. Very large diamond targets were prepared to investigate the interaction of Ξ particles with carbon nuclei. The high density of diamond significantly increases the probability that the Ξ will interact before it decays. The present target construction depended on the availability of commercially produced 1-cm square diamond wafers which could be assembled into 1-cm cubes. Targets of 40 cm³ for Brookhaven AGS experiment E885 and 16 cm³ for an experiment at the KEK Laboratory, Japan, were made. Analysis of the E885 data confirmed the higher yield with diamond over lower-density carbon targets