Condensation particle counter

This is of special importance because particles sized down from 50 nm are generally undetectable with conventional optical techniques.

100…200 % in condensation chamber, despite the fact that heterogeneous nucleation (droplet growth on surface of a suspended solid particle) can occur at supersaturation as small as 1%.

The greater vapour content is needed because, according to surface science laws, the vapour pressure over a convex surface is less than over a plane, thus greater content of vapor in air is required to meet actual supersaturation criteria.

The supersaturation level must, however, be small enough to prevent homogeneous nucleation (when liquid molecules collide so often that they form clusters – stable enough to ensure further growth is possible), which will produce false counts.

In order to ensure a high vapour content, the working liquid is in contact with a hollow block of porous material that is heated.