This study investigates a method to prevent aerosol particle adhesion on resin substrates commonly used in glove box panels and transparent materials. A cationic polyelectrolyte (polyethyleneimine) was used to modify the resin surface without using organic solvents to improve affinity with silica nanoparticles dispersed in water. Diluted silica nanoparticle dispersions were airbrushed onto surface modified acrylic and polycarbonate substrates. The resulting coatings were evaluated by visual inspection, optical microscopy, atomic force microscopy, and colloid probe adhesion measurements. The results showed that the silica dispersion with 0.1 mass% exhibited the highest surface roughness and lowest particle adhesion, reducing adhesion to 13.8 % and 9.6 % for acrylic and polycarbonate, respectively. Importantly, the transparency of the substrate material was maintained after coating, confirming its practical applicability. These results indicate that nanoparticle coating methods using polyelectrolyte surface modification effectively reduce particle adhesion while maintaining material transparency and provide a low-cost, simple approach applicable to safety-critical environments.

In Japan, Americium-241 (Am-241) has long been used as an ion source for aerosol neutralizers in Scanning Mobility Particle Sizers (SMPS). However, due to the manufacturer’s discontinuation of production, sales by the Japan Radioisotope Association ceased at the end of 2021. To address this issue, we developed a prototype aerosol neutralizer using a sealed Nickel-63 (Ni-63) source with an activity of 100 MBq as an alternative ion source. According to Japanese regulations, the lower limit for a sealed Ni-63 source is 100 MBq. Since the activity of the source used in our prototype does not exceed this threshold, the device is not subject to regulation, and no notification to the Nuclear Regulation Authority is required for its use, modification, or disposal. In this study, we evaluated the charge conditioning performance of the Ni-63 aerosol neutralizer by comparing it with the conventional Am-241 neutralizer and the charging probability values used in SMPS. The results showed that, under certain conditions, the differences were non-negligible compared to the reference values. However, in most cases, the particle concentration and charging probabilities were within acceptable ranges. These findings confirm that Ni-63 is a viable alternative ion source, particularly given the unavailability of Am-241 in Japan.