Femtocoulomb range triboelectric noise meter for super-low noise cables

Bending, twisting or vibrations in coaxial and multi-wire cables can generate signal noise, often dominated by triboelectric charging effects. Cables that ensure low triboelectric noise are called low noise cables. These cables are used in many low-level measurement applications such as medical instruments and sensors in nuclear plant. In this work, we have designed a triboelectric charge meter that can detect and amplify charges at sub-femtocoulomb levels, sufficient to characterize the triboelectric noise in a wide range of high performance coaxial cables. During loop bending tests of, standard-, low noise-, and super-low noise coaxial cables, average microphonic noise levels of 2600 fC, 142 fC, and 2.9 fC respectively, were measured, i.e. super-low noise coaxial cables exhibits an almost 60 dB reduction of the triboelectric noise compared to standard coaxial cables and 35 dB compared to low noise cables.