COMPARISON OF THE HOLLOW ELECTRON BEAM DEVICES AND ELECTRON HEATING

In the previous two years after COOL05 a new generation of low energy electron coolers with variable electron beam profile was successfully commissioned with Pb +54 ion beams at CERN LEIR and at IMP (China, Lanzhou) CSRm with C +6 . A hollow electron beam profile with low electron beam density at the center helps to suppress recombination at the accumulation zone and to increase the lifetime of the ion beam. First experiments with a vertically offset electron beam (with aim to control overcooling the storage stack of ion beam) were made at the RECYCLER high energy electron cooler (FNAL) with very different conditions for accumulation and cooling antiprotons. In this paper the parameters of these different experiments with electron cooling are discussed in the frame of a model of electron heating. The aim is to integrate the experience of using the hollow electron beam cooling, test model and to find recommendations for the next generation electron coolers for the FAIR p.