GranvillePhillips Alpert Type Ionization Gauge （GranvillePhillips Alpert类型电离真空计）.pdfVIP

Granville-Phillips® Series 274 Bayard- Alpert Type Ionization Gauge Tube CRITICAL COMPONENTS GROUP VACUUM PRODUCTS Operating Principle The pressure indication of a Bayard-Alpert (a hot cathode) gauge is based on the ionization of gas molecules by a constant flow of electrons. The negative electrons are emitted at a well-controlled, selectable rate from a heated cathode and are accelerated toward a positively charged wire grid (anode). Electrons pass into the space between the grid and a collector wire at ground. In this space the electrons collide with gas molecules from the vacuum Benefits system, producing positive ions. The positive ions are then collected by the grounded • Good vacuum pressure collector wire that is located along the axis of the cylindrical grid. At a constant filament to measurement for economical cost grid voltage and electron emission current, the rate that positive ions are formed is directly • Operates on industry proportional to the density of molecules (pressure) in the space for pressures below 1 x 10-3 standard electrode voltages and wide range of electron Torr. The strength of the ion current is then indicated on a microammeter that is calibrated emission currents (10 µA in units of pressure. Inasmuch as the pressure indication is linear, the hot cathode Bayard- to 10 mA) Alpert gauge is gen