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Abstract. Glaciation in mixed-phase clouds predominantly occurs through theimmersion-freezing mode where ice-nucleating particles (INPs) immersedwithin supercooled droplets induce the nucleation of ice. Modelrepresentations of this process currently are a large source of uncertaintyin simulating cloud radiative properties, so to constrain these estimates,continuous-flow diffusion chamber (CFDC)-style INP devices are commonly usedto assess the immersion-freezing efficiencies of INPs. This study explored anew approach to operating such an ice chamber that provides maximumactivation of particles without droplet breakthrough and correction factorambiguity to obtain high-quality INP measurements in a manner thatpreviously had not been demonstrated to be possible. The conditioningsection of the chamber was maintained at −20 ∘C and water relative humidity (RHw) conditions of 113 % to maximize the droplet activation,and the droplets were supercooled with an independentlytemperature-controlled nucleation section at a steady cooling rate(0.5 ∘C min−1) to induce the freezing of droplets andevaporation of unfrozen droplets. The performance of the modified compactice chamber (MCIC) was evaluated using four INP species: K-feldspar,illite-NX, Argentinian soil dust, and airborne soil dusts from an arableregion that had shown ice nucleation over a wide span of supercooledtemperatures. Dry-dispersed and size-selected K-feldspar particles weregenerated in the laboratory. Illite-NX and soil dust particles were sampledduring the second phase of the Fifth International Ice Nucleation Workshop(FIN-02) campaign, and airborne soil dust particles were sampled from anambient aerosol inlet. The measured ice nucleation efficiencies of modelaerosols that had a surface active site density (ns) metric were higher but mostly agreed within 1 order of magnitude compared to results reported in the literature.
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