Calibration of Optical Particle Spectrometers Using Mounted Fibres

Abstract. Calibrations of OPSs are non-trivial, and conventionally involve aerosolisation techniques which are challenging for larger particles. In this paper, we present a new technique for OPS calibration, which involves mounting a static fibre within the instrument sample area, measuring the scattering cross section, then comparing it with a calculated value. In addition, we present a case for the use of GLMT simulations to account for deviations in both minor and major axis beam intensity, which has a significant effect on particles which are large compared to the beam waist, in addition to reducing the need for a ‘top-hat’ spacial intensity profile. The described technique is OPS independent and could be applied to a field calibration tool, which could be used to verify the calibration of instruments before they are deployed. In addition to this, the proposed calibration technique would be suited for applications involving mass production of low-cost OPSs.