Development of an CNT field emission UHV ionization gauge with customized electronics

An ionization vacuum gauge with carbon nanotube (CNT) cathode was designed for measurement of ultra high vacuum (UHV). The sensor was constructed based on Bayard-Alpert type gauge. The key index of the control unit is determined by theoretical analysis and experimental results. A customized detection circuit was designed considering the characteristics of the output ion current of the sensor, the performance of which, such as linearity, noise, bandwidth and gain, were determined by a series of tests and calibrations. At last, the vacuum measurement range and uncertainty of this gauge were determined. The test results showed that the lower limit of the CNT-cathode ionization vacuum gauge enters 10-8Pa, The measurement uncertainty is about 4.0% in the pressure range of 10-4Pa-10-7Pa. This work can provide a new solution for UHV measurement.