A fog chamber from the well-known physics company PHYWE is the given focus of many exhibitions. Every day, thousands of visitors to technical museums, art museums, nuclear power plant information centers, universities and colleges are fascinated by these fog chambers that make the invisible background radiation visible. PHYWE has been developing and manufacturing these unique devices for more than 20 years. In total, there are more than 200 in operation in more than 40 countries. The fog chamber makes the invisible visible. Every second you can observe a large number of traces that originate from both cosmic radiation and the earth's natural radioactivity. The appearance of the trace immediately reveals the type of particle that has just passed. During normal operation, no additional preparation is used. If you want to increase the activity in the surface, you can blow in a thorium isotope.

Isopropyl alcohol is pumped from the mist chamber tank up to a chute with heating wire. There, the liquid evaporates, rises upwards, cools and sinks slowly towards a plate with a temperature of about -30 ° C. The steam becomes supersaturated and forms a surface layer of about 1-2 mm. It is in this layer that the traces emerge. The supersaturated steam is slowly converted to liquid alcohol and flows back to the tank.

Traces of all electrically charged particles can be observed in the fog chamber e.g. alpha particles, protons, muons, electrons and positrons. A fog chamber is a high-tech thermodynamic system. It is tested, tested and fine-tuned for several days before delivery. Phywe manufactures 2 different models, one large and one small. The activity areas are 80 × 80 cm and 45 × 45 cm respectively. A fog chamber is energy efficient, easy to operate and requires almost no supervision. The alcohol tank is filled with 2 liters of isopropyl alcohol. Press the start button and after 15-20 minutes the process has started and the tracks start to appear. Start and stop are performed manually or automatically with the built-in timer.