  We propose the use of neutron poisons in reactions induced by radioactive
beams as a test of theoretical models aiming to relate neutron capture in
nuclei with neutron surrogate reactions such as (d,p) reactions. We exploit the
approximations necessary to obtain a direct relation between the two reactions;
surrogate vs. neutron capture. We also show how this is intimately related to
the momentum distribution of the neutron within the deuteron. The models we use
are based on the theory of inclusive breakup reactions commonly employed in the
treatment of incomplete fusion and surrogate method. Such theories were
developed in the 80's by Ichimura, Autern and Vincent [Phys. Rev. C 32, 431
(1985)], Udagawa and Tamura [Phys. Rev. C 24, 1348 (1981)] and Hussein and
McVoy [Nucl. Phys. A 445, 124 (1985)]. We use these theories to derive an
expression for the proton yield in the reaction A(d,p)B. The capture reaction
$n + A \rightarrow B$ is then extracted using reasonable approximations. By
recalling an old method proposed by Serber [Phys. Rev. 80, 1098 (1950); Nature
166, 709 (1950)] we explain how the momentum distribution of neutrons within
the deuteron will depend on the short-range dependence of the nucleon-nucleon
force. The relevance of our work to nucleosynthesis in the rapid neutron
capture process is emphasized.
