Impedance and Noise Closed-Form Model of Large-Area Integrated Resistors With High Stray Capacitance to be Used as Feedback Discharge Devices in Charge-Sensitive Preamplifiers for Nuclear Spectroscopy

In this article, a theoretical study and the experimental measurements have been conducted in order to describe both the impedance and the noise associated with resistors with appreciable distributed stray capacitance. In particular, the effects of using such devices as feedback discharge for nuclear spectroscopy charge-sensitive preamplifiers have been analyzed. A closed-form model shows that for frequencies higher than $1/(2\pi \cdot \textit {RC}/2)$ , the generated noise is not white anymore, and the power spectral density of noise raises with the square root of frequency. The experimental measurements confirm the model validity.