Two-neutron emission from electromagnetic dissociation of 59Co and 197Au targets by relativistic heavy ions.

Electromagnetic dissociation of /sup 59/Co and /sup 197/Au target nuclei and their subsequent deexcitation by two-neutron emission was observed. Beams of relativistic /sup 12/C, /sup 20/Ne, /sup 40/Ar, /sup 56/Fe, and /sup 139/La ions were used. The measured electromagnetic dissociation cross sections become large for high-Z targets and projectiles, reaching 335 mb for the /sup 197/Au(/sup 139/La,X)/sup 195/Au reaction with 1.26 GeV/nucleon /sup 139/La projectiles. The experimental cross sections in excess of the estimated nuclear contributions are in reasonable agreement with a calculation of the electromagnetic dissociation contribution using the Weizsaecker-Williams method for estimating the virtual photon spectrum.