Experimental search for free quarks in matter

An apparatus has been constructed for the measurement of very small electric charges on macroscopic particles with a charge resolution better than 0.05e. Together with the charge measurement system, a generator of small liquid particles has been assembled and used to test the system. To achieve the charge resolution desired, some of the problems which were solved included particle interactions resulting from induced dipoles, particle position and timing measurements to accuracies of a few microns and nanoseconds, operation in high vacuum to avoid aerodynamic effects, and spurious charging of the particles by external effects. The technique, which depends on simple, straight-forward deflection of particles in an electric field, is described and some particle charge measurements are presented.