The Charme^® charge aerosol measurement system developed by Palas^® is a high-capacity Faraday cup aerosol electrometer that measures the electrical charges on aerosol particles.

For years, aerosol electrometers have been used in research applications to measure the mean charge of an aerosol. If the charge state of the particles for monodisperse aerosols is known, then these devices can quickly and easily determine the number concentration of particles with an approx. size ≥ 2 nm.

In the case of polydisperse aerosols, a charger or neutralizer is often used to generate a defined charge distribution. If a particle size is set using an upstream classifier (e.g., Palas^® DEMC), then the number concentration of the particles can be determined indirectly based on a current measurement (load/time). An aerosol electrometer is often used to calibrate condensation particle counters (e.g., Palas^® UF-CPC). There is no absolute particle count standard. However, a current measurement is directly traceable to SI units. Condensation particle counters can be calibrated based on a counting comparison between the condensation particle counter and an aerosol electrometer.

The Charme^® reference aerosol electrometer for concentration measurements within the size range of 2 nm to 100 μm* features reliable performance, components of optimal quality, and easy operation using the touch screen. The extremely fast (10 Hz) particle concentration and electrometer current measurements are displayed graphically in real-time.

An on-site correlation between the measured current (particle charges) and the mass concentration can be determined using a gravimetric filter, which the user can switch out. As a result, the Palas^® Charme^® aerosol electrometer is particularly well suited for verifying high particle loads in the environment and in the workplace, as well as for calibrating condensation particle counters (CPCs).

The Charme^® achieved excellent measurement results compared to established electrometers at Switzerland's Federal Office for Metrology (METAS).

* The upper particle size limit depends on the aerosol transport of large particles, i.e., primarily on aerosol sampling and the upper measurement range limit for current measurement.