公开(公告)号：US3866077A

公开(公告)日：1975-02-11

申请号：US26913972

申请日：1972-07-05

Applicant: NAT RES DEV

Inventor： BAKER FRANCIS SIDNEY ,  HARRISON CHARLES RICHARD ,  OSBORN ANTHONY RAYMOND ,  WILLIAMS JOHN

IPC: G01Q30/08 ,  G01Q30/16 ,  G01Q70/12 ,  H01J1/304 ,  H01J37/073 ,  H01J37/24 ,  H01J1/16

CPC classification number: H01J1/304 ,  H01J37/073 ,  H01J37/241 ,  H01J2201/30457

Abstract: A carbon filament such as a carbon fibre or graphite whisker is used as a source of field emission electrons in an electronic device such as an electron microscope or an electron beam machining device. A vacuum of only 10 7 torr is required, and electrical noise in the beam may be reduced by momentarily heating the source in vacuum before use, and/or by using an electrical current stabilisation circuit.