[en] The 50 GW Nd-glass laser at the Lockheed Palo Alto Research Laboratory was employed to produce inertially-confined plasmas, and the 3-MV Van de Graaf accelerator was employed as the source of the diagnostic proton beam. The overall system is conveniently divided into three basic subsystems: the Particle Beam Control System delivers a pulsed, monochromatic, and tightly focused beam of protons at the target spot; the Time-Energy Analysis System analyzes the transmitted beam in time and energy coordinates; and the Laser Timing and Synchronization System coordinates the interaction of the particle and laser beams. These three subsystems were completed in December, 1976, and tests of the combined system were carried out over the next several months. The results of these tests have indicated that the particle transmission technique is a feasible approach to density measurement in inertially-confined plasmas. Adequate solutions to the problems of background, temporal synchronization, and spatial overlap are demonstrated in this report. Further attention should be devoted to the problem of beam luminosity and to direct experimental verification of the time-resolution capability of the TEAS. The study of dE/dx, a problem of considerable importance to current fusion research in inertially-confined plasmas, offers the best immediate practical application for the system assembled under this contract and is recommended as a follow-on effort