Metrological properties of an ionization gauge with carbon nanotube cathode in different gases

A Cylindrical Triode Ultrahigh Vacuum Ionization Gauge with a Carbon Nanotube Cathode

“…Thus, the metrological behaviors of the modified ionization gauge with a CNT electron source were investigated under a low anode current together with constant electrode voltages, as demonstrated in Figure 1 b. In this situation, the anode current was only about 20 μA, which is high enough for extremely low pressure measurement, according to our previous experience [ 11 , 14 , 17 ].…”

“…Finally, in order to determine the linear pressure measurement range of the present ionization gauge with a CNT cathode, the background signal obtained under the ultimate pressure condition was processed with the same procedure as described in Refs. [ 14 , 23 ]. The original cylindrical triode ionization gauge and the schematic diagram of the modified ionization gauge with a CNT electron source used in this work are illustrated in Figure 1 .…”

“…The detailed variation of sensitivity of this ionization gauge will be further discussed below. The gauge sensitivity is a key parameter for pressure sensing, which is related to several factors, including the gauge physical structure, the electrode voltage, and the gas species [5,10,14]. In general, a high sensitivity is necessary for an ionization gauge with a low anode current to monitor the extremely low pressure [44].…”

“…At constant gate voltages (250 and 300 V), the trend of sensitivity with anode voltage, obtained by the experimental method, is consistent with the one gained by theoretical simulation, as demonstrated in Figure 6. It is generally believed that the gauge sensitivity is determined by the ionization cross-section of gas molecules as well as The gauge sensitivity is a key parameter for pressure sensing, which is related to several factors, including the gauge physical structure, the electrode voltage, and the gas species [5,10,14]. In general, a high sensitivity is necessary for an ionization gauge with a low anode current to monitor the extremely low pressure [44].…”

“…However, conventional ionization gauges have long-standing intractable problems when measuring extremely low pressure, i.e., X-ray effects, electron-stimulated desorption effects, and outgassing effects [ 1 , 6 , 7 ]. Fortunately, recent studies [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ] have shown that ionization gauges with carbon nanotube (CNT) cathodes have unique advantages, such as low power consumption for electron emissions, fast responses, free from visible to infrared light radiation and thermal radiation, etc., in extremely low pressure measurements, which are largely due to the application of the novel CNT field emission cathode. For instance, Murakami et al [ 9 ] reported the application of a CNT field emission cathode in a Bayard–Alpert gauge (BAG) for the first time in 2001, and the lower limit of pressure measurement by this novel sensor was approximately 1 × 10 −4 Pa. Dong et al [ 8 ] reported on the design and investigation of a commercial extractor gauge (Leybold, IE 514) with a CNT cathode, which showed excellent measurement linearity from 10 −10 to 10 −6 Torr in nitrogen.…”