  Measurements of the pn -> p_spec dK^+K^- reaction, where p_spec is a
spectator proton, have been undertaken at the Cooler Synchrotron COSY-Juelich
by detecting a fast deuteron in coincidence with a K^+K^- pair in the ANKE
facility. Although the proton beam energy was fixed, the moving target neutron
allowed values of the non-resonant quasi-free pn -> dK^+K^- total cross section
to be deduced up to an excess energy epsilon ~ 100 MeV. Evidence is found for
the effects of K^-d and KKbar final state interactions. The comparison of these
data with those of pp -> ppK^+K^- and pp -> dK^+Kbar shows that all the total
cross sections are very similar in magnitude.
