An analysis is made of the reasons for the onset of a Penning discharg
e in electron-optical devices operating at moderate and high vacuum in
the presence of an accompanying magnetic field. Methods of suppressin
g this discharge are recommended. The main results of tests to elimina
te the Penning discharge in the test rig at the Joint Institute of Nuc
lear Research (Dubna) and in the CERN Low Energy Antiproton Ring (LEAR
) (Geneva) are presented. (C) 1997 American Institute of Physics. [S10
63-7842(97)02411-2].