Electron gun and collector for the Fermilab high-energy electron cooling

In this paper, we discuss results of 25–50 kV electron gun and collector bench tests performed as part of the R&D program to develop MeV-range electron cooling at Fermilab. We found that by controlling the cathode emitting area using a negatively biased electrode one can form an electron beam with an extremely small halo. We also present results of the tests for the electron collector with a transverse magnetic field. One can show that for this type of collector the flux of secondary electrons is about 100 times smaller than the flux in a traditional axially symmetric scheme with a potential barrier.