US 4,467,205 AGranted

Highly-steady beam generating for charged particles

AssigneeDr. Ing. Rudolf Hill GmbH

InventorsSiegfried Beisswenger, Wolfgang Boppel

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Abstract

An electron beam generating system provides a high degree of steadiness of the beam current and comprises a heated cathode, an auxiliary electrode lying at a more negative potential than the cathode, and a transpierced anode. A diaphragm surrounding the beam and connected to a precision resistor is further provided at that side of the auxiliary electrode facing away from the cathode. A portion of the beam current influenced by the control electrode is blanked out by the diaphragm. The precision resistor is connected as an actual value generator to a regulator which is connected to a reference voltage, the output of the regulator influencing the potential of the control electrode over a final control element for the purpose of maintaining the beam current measured by the diaphragm constant.

Claims5

Dependent claims

In an electron beam generating system which comprises a heated cathode for generating an electron beam an auxiliary electrode and a transpierced anode, the improvement comprising:

a diaphragm structure surrounding the electron beam at the side of the auxiliary electrode which is opposite to the cathode;
a precision resistor connected to said diaphragm structure for developing a voltage drop in response to a portion of the electron beam striking said diaphragm structure,
a voltage regulator connected to a reference voltage and connected to said precision resistor for developing a control voltage;
and
a control element connected between said voltage regulator and the auxiliary electrode for applying a control potential to the auxiliary electrode in response to the control voltage as a correction measure of that portion of the electron beam striking said diaphragm structure.

2 more elements

Dependencies are inferred from the claim text.