In-channel particle position and velocity detectors based on particle transit time across uneven inter-gap electrodes

We present the first proposal to detect both particle position and velocity based on the electrical measurement of particle transit time across uneven inter-gap electrodes. Compared to the previous methods, the present detector provides higher integrability for chip-based systems and achieves higher measurement stability robust to particle size variation. The position uncertainty of polystyrene particles is measured as 3.3%. Particle velocity uncertainty is measured as 2.21% from the fabricated devices, achieving 2.4 times improvement compared to the uncertainty of 5.38% from the conventional optical methods. The stable performance of the present detector insensitive to particle size variation is also verified by the experiments using different particle sizes.