Modelling signal oscillations arising from electro-thermal coupling and stray capacitance in semiconducting bolometer impulse response

TL;DR

This paper presents a physical model explaining oscillations in the impulse response of semiconductor bolometers caused by electro-thermal coupling and stray capacitance, validated by experimental data.

Contribution

It introduces a novel physical model that captures the effects of electro-thermal coupling and stray capacitance on bolometer response, supported by experimental validation.

Findings

Model reproduces observed impulse response oscillations

Oscillations depend on electro-thermal coupling and stray capacitance

Validates the importance of these effects in detector response

Abstract

Electro-thermal coupling in semiconductor bolometers is known to create nonlinearities in transient detector response, particularly when such detectors are biased outside of their ideal regions (i.e. past the turnover point in their IV curves). This effect is further compounded in the case where a stray capacitance in the bias circuit is present, for example in long cryogenic cabling. We present a physical model of the influence of such electro-thermal coupling and stray capacitance in a composite NTD germanium bolometer, in which previous experimental data at high $V_{\rm bias}$ resulted in oscillations of the impulse response of the detector to irradiation by alpha particles. The model reproduces the transient oscillations seen in the experimental data, depending both on electro-thermal coupling and stray capacitance. This is intended as an experimental and simulated example of such oscillations, demonstrated for the specific case of this bolometric detector.