Title:
ELECTRON SOURCES UTILIZING NEGATIVE ELECTRON AFFINITY PHOTOCATHODES WITH ULTRA-SMALL EMISSION AREAS
Document Type and Number:
WIPO Patent Application WO1997003453
Kind Code:
A3
Abstract:
An electron source includes a negative electron affinity photocathode on a light-transmissive substrate and a light beam generator for directing a light beam through the substrate at the photocathode for exciting electrons into the conduction band. The photocathode has at least one active area for emission of electrons with dimensions of less than about two micrometers. The electron source further includes electron optics for forming the electrons into an electron beam and a vacuum enclosure for maintaining the photocathode at high vacuum. In one embodiment, the active emission area of the photocathode is defined by the light beam that is incident on the photocathode. In another embodiment, the active emission area of the photocathode is predefined by surface modification of the photocathode. The source provides very high brightness from an ultra-small active emission area of the photocathode.
Inventors:
BAUM AARON W
COSTELLO KENNETH A
COSTELLO KENNETH A
Application Number:
PCT/US1996/010978
Publication Date:
April 03, 1997
Filing Date:
June 27, 1996
Export Citation:
Assignee:
INTEVAC INC (US)
UNIV LELAND STANFORD JUNIOR (US)
UNIV LELAND STANFORD JUNIOR (US)
International Classes:
G03F7/20; H01J37/06; H01J1/34; H01J3/02; H01J27/04; H01J37/073; (IPC1-7): H01J/
Foreign References:
| US4460831A | 1984-07-17 | |||
| US4970392A | 1990-11-13 | |||
| US4868380A | 1989-09-19 |
Other References:
STANFORD C.A.: "Laser Pulsed GaAs Negative Electron Affinity Photocathodes for Electron Beam Instrumentation", CORNELL UNIVERSITY DEPT. OF ELECTRICAL ENGINEERING, 1990
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