[en] This report describes experimental results from a series of electron beam experiments conducted intermittently in the very large NASA vacuum chambers at Plum Brook and JSC from Dec. 1974-Dec. 1976. Principal objectives were the study of beam dynamics and beam-plasma interactions in the unique low B(0.3G), low electron density (100,000/cc), long path length (20m) configurations possible in these chambers. Details of the experimental configuration and diagnostics instrumentation are given