JP2720907B

This source for intense coherent electron pulses of an energy below 1 keV comprises an ultrasharp electron-emitting tip (10) and an anode (11), both arranged in mutual alignment inside a vacuum envelope (9). A pulsed potential with an amplitude in the range between 100 V and 500 V and with a variable pulse rate is applied between said tip (10) and said anode (11). The tip (10) is maintained negative with respect to said anode (11), the tip (10) having a sharpness such that the electric field at its surface exceeds 10 V/cm at said pulsed potential. An object (14) is arranged downstream in front of the opening (12) in said anode (11) within the electron beam, such that the spherical wave of electrons arriving at a screen (13) arranged opposite said tip (10) and oriented orthogonally with respect to the axis of the electron beam passing said opening (12), generates an interference pattern thereon, namely a Gabor hologram in case said object (14) is smaller than the diameter of said opening (12), and a transmission hologram in the case said object (14) is bigger than the diameter of said opening (12) and at least partially transparent to the electron beam.