Effective beam energy spreads with molecular ion beams

For several reasons it is sometimes desirable or necessary to use molecular hydrogen beams to produce nuclear reactions for materials analysis purposes. This paper presents the results of a study of the detailed characteristics of (p, γ) resonance yield curves obtained with molecular beams. Experimental gamma-ray yield curves have been measured (1) for the H2+ beam on a thick aluminum target (992 keV resonance) and (2) for the H10 beam (stripped from the H2+ beam in a gas cell) on a thin aluminum target. Each of these yield curves has been calculated in detail from first principles and with no free parameters. The agreement between theoretical and experimental curves is excellent, leading to confidence that one can correctly interpret the peculiar features of yield curves from the H2+ beam and from its stripped components. (Auth.)