Performance of the Fermilab's 4.3 MeV electron cooler

A 4.3 MeV DC electron beam is used to cool longitudinally an antiproton beam in the Fermilab's Recycler ring. Cooling capabilities of the electron beam are characterized by the drag rate that was measured at various conditions. Fitting the results with a formula for non-magnetized cooling gives electron parameters that agree within a factor of 2 with independently measured electron beam properties.