We have measured the quasiparticle generation-recombination (GR) noise in aluminium lumped element kinetic inductors with a wide range of detector volumes at various temperatures. The basic detector consists of meandering inductor and interdigitated capacitor fingers. The inductor volume is varied from 2 to 153 {\mu}m^{3} by changing the inductor width and length to maintain a constant inductance. We started with measuring the power spectrum density (PSD) of the detectors frequency noise which is a function of GR noise and we clearly observed the spectrum roll off at 10 kHz which corresponds to the quasiparticle lifetime. Using data from a temperature sweep of the resonator frequency we convert the frequency fluctuation to quasiparticle fluctuation and observe its strong dependence on detector volume: detectors with smaller volume display less quasiparticle noise amplitude. Meanwhile we observe a saturated quasiparticle density at low temperature from all detectors as the quasiparticle life time {\tau}qp approaches a constant value at low temperature.
@article{arxiv.2304.01156,
title = {Quasiparticle Generation-Recombination Noise in the Limit of Low Detector Volume},
author = {J. Li and P. S. Barry and T. Cecil and C. L. Chang and K. Dibert and R. Gualtieri and M. Lisovenko and Z. Pan and V. Yefremenko and G. Wang and J. Zhang},
journal= {arXiv preprint arXiv:2304.01156},
year = {2023}
}