New electronics for an ionization chamber

A two-channel instrument is developed in the Institute of Nuclear Physics for measuring currents of ionization chamber in the range of 5 × 10−15 to 3 × 10−6 A. The unit has two low-noise current amplifiers, analog-to-digital converters with programmable bandwidth, a programmable high-voltage power supply (0–1100 V), and an interface for communicating with the user’s computer. Despite an abundance of digital and analog subsystems, the device’s intrinsic noise is reduced to the estimated minimum. When the band-width of measured currents is set to 1 Hz, the mean-square noise does not exceed 5 fA. The functionality of the device allows it to be used not only with ionization chambers, but also in other studies that require measurements of ultra-low currents, e.g., PH-metry, or in studies of semiconductor structures. © 2015, Allerton Press, Inc.