US 4,066,905 AGranted

Particle beam apparatus with zones of different pressure

AssigneeSiemens Aktiengesellschaft

InventorsJoachim Dassler, Lee H. Veneklasen, Martin Zschimmer

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Abstract

An improved particle beam optical apparatus of the type having an evacuated housing with two sequential zones along the beam axis to be maintained at different low absolute pressures. A pressure stage detachably mounted in the housing between the zones is divided by an apertured partition into two portions communicating with the respective zones. From each portion a conduit leads through the body of the pressure stage for connection to respective vacuum pumps, the centerlines of the conduits lying in a common plane perpendicular to the beam axis. The body of the pressure stage preferably is adjustably mounted in a rigid support ring that is attached in vaccum-tight relation to the housing. The arrangement simplifies the vacuum connections, minimizes distortion of the housing and misalignment of the beam generating and control elements, and provides adjustment capability of the partition aperture.

Claims7

Dependent claims

A particle beam optical apparatus of the type having means for directing a beam of charged particles along an axis, a housing surrounding the particle beam axis, and means located at an intermediate position along the beam axis for dividing the housing into two subspaces following sequentially along the beam axis, one of the subspaces being adapted to be evacuated to a first low pressure, and the other being adapted to be evacuated to a second low pressure higher than the first low pressure, wherein the means for dividing the housing into two subspaces comprises:

a pressure stage having a body that is detachably mounted in vacuum-tight relation to the housing at said intermediate position, the pressure stage including
a vacuum-tight partition dividing said body into a first portion communicating with the one subspace and a second portion communicating with the other subspace,
a first conduit leading from said first portion through the body and adapted for connection to a means for evacuating the one subspace to said first low pressure, and
a second conduit leading from said second portion through the body and adapted for connection to a means for evacuating the other subspace to said second low pressure,
the centerlines of said first and second conduits lying approximately in a common plane perpendicular to the beam axis.

2 more elements

Dependencies are inferred from the claim text.