Total radiative recombination rates for ions interacting with electrons from an electron cooler

We give closed form expressions for the total radiative recombination rate for low-energy electrons, as in the process of electron cooling of an ion beam in the electron cooler of a storage ring. The rate is derived for the Maxwellian electron beam velocity distribution of arbitrary asymmetry, given by the longitudinal and transverse electron beam temperatures. An influence of the field-ionization effect on recombination rates is discussed in terms of a simple cut-off model. The results are compared with recent experimental data on radiative recombination. ((orig.))