工作原理
The pressure indication of a Bayard-Alpert (a hot cathode) gauge is based on the ionization
Granville-Phillips真空计 GP 274真空电离规（热阴极）真空计是基于电离气体分子由一个恒定的电子流。负电子发出的很好的控制，可选择的速度从加热的阴极和加速朝向正charged wire grid (anode). Electrons pass into the space between the grid and a collector wire带电的线栅（阳极）。电子传递到空间网格和集电极之间的线at ground. In this space the electrons collide with gas molecules from the vacuum system,在地面。在这个空间中与电子碰撞气体分子从真空系统，producing positive ions. The positive ions are then collected by the grounded collector wire产生的正离子。正离子通过集电极接地收线that is located along the axis of the cylindrical grid. At a constant filament to grid voltage位于沿圆柱形网格轴线。在一个恒定的灯丝电压and electron emission current, the rate that positive ions are formed is directly proportional电子发射电流，这是正离子形成的速率是成正比的to the density of molecules (pressure) in the space for pressures below 1 x 10-3 Torr. The分子的密度（压力）低于1×10-3乇的压力在空间。的strength of the ion current is then indicated on a microammeter that is calibrated in units of离子电流强度是然后在微安表，单位校准指示pressure. Inasmuch as the pressure indication is linear, the hot cathode Bayard-Alpert gauge压力。由于压力指示是线性的，热阴极B-A规is generally considered the most accurate continuous indicator for pressures below 1 x 10-3一般认为是低于1×10-3压力精确的连续指示器Torr.。The low end of the operating range of a Bayard-Alpert gauge is determined by the X-ray limit对B-A规经营范围的低端是由X射线的限制确定of this type of gauge. The X-ray limit varies with different gauge designs. X-rays are produced这种类型的表。X射线的限制不同规范设计的变化。所产生的X射线when the electrons emitted by the cathode impact the grid and support wires. Because of当由阴极发射的电子的影响，支持网格线。由于the geometry of the Bayard-Alpert gauge, only a small fraction of the emitted X-rays are的B-A规大小，只有一小部分发出的X射线intercepted by the ion collector. When the X-rays strike the collector wire they cause electrons通过离子收集器截获。当X射线撞击器所造成的电子线to be photoelectrically ejected from the collector. This X-ray current limits the pressures that是集光电喷出。这种X射线的电流限制的压力can be measured, and is equivalent to a pressure reading in the 10-10 or 10-11 Torr ranges,可以测量的，相当于在10-10或10-11乇范围压力读数，depending upon the gauge model. Earlier gauges that had a cylindrical collector outside the根据规范模型。早期的仪表，有外圆柱集热器grid experienced an X-ray limit of about 10-8 Torr. The X-ray limit refers to the lowest pressure网格经历了约10-8乇的X射线极限。X射线的限制是指压力indication that may be obtained in a gauge when all the output current is due to X-ray induced迹象表明可能在测量时获得的所有的输出电流是由于X射线诱导的photoemission and there is an absence of gas.光电子能谱和有气没有。
美国Granville-Phillips真空计 GP 274真空电离规：
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