Traceable low-current measurements for a novel ionization gauge suitable as reference standard

A novel ionization gauge was developed where the electron beam is guided through the ionization space in a straight path. This design was chosen in order to develop a more stable ionization vacuum gauge suitable as reference standard in the range of 10−6 Pa to 10−2 Pa. The design requires a low electron current resulting in even lower ion currents. For the purpose of a reference standard, these ultra-low currents in the range 1 pA–100 nA need to be measured in a traceable manner. For the first time, an ultrastable low-noise current amplifier was used for this purpose.