Patent ID: 8350572

Claim:
An ionization vacuum device for use as a cold cathode ionization vacuum gauge, comprising: a vacuum vessel; an anode provided inside said vacuum vessel; a cathode provided inside said vacuum vessel; a power source for discharge, connected to said anode, that supplies electric power for discharge between said anode and said cathode; a power source for cathode-heating that is connected between terminals of said cathode and that supplies power for heating to said cathode; means for forming a magnetic field in a space between said anode and said cathode, with said vacuum vessel connected to another vacuum vessel to measure a pressure inside the another vacuum vessel; and temperature control means for controlling the heating of said cathode by said power source for cathode-heating, while creating the discharge between the anode and the cathode, so as to maintain the temperature of said cathode within a temperature range where thermonic electrons are not emitted from said cathode and whereby attachment of contaminating materials to the cathode is reduced.