A crossed molecular beam apparatus is used to study ionizing collisions of energetic cesium atoms with Cl2, Br2, and I2. The cross sections for formation of Cs+ are reported in the near−threshold region. The experiment combines an energy resolution better than 0.1 eV (FWHM) with a deconvolution procedure. An electron affinity of 2.50 eV is deduced for all three halogens, in good agreement with previous work. In a separate experiment, with cesium energies from threshold to 350 eV, and with much poorer energy resolution, the intensity ratios X−/X−2 are obtained. The results can be reasonably explained with an electron jump model. At energies below 30 eV, the observed ratios are in agreement with two other investigators, but between 150−350 eV they are drastically different from work reported from a third. Complementary data recently reported by a fourth group are difficult to reconcile with the present results.