CPC Subgroup
H01J 23/07 producing a hollow cylindrical beam (H01J23/075 takes precedence)
Full Title
Details of transit-time tubes of the types covered by group H01J25/00 > Electrodes; Magnetic control means; Screens (associated with resonator or delay system H01J23/16) > Electron or ion guns > producing a hollow cylindrical beam (H01J23/075 takes precedence)