Integrating Cylinder Improves Smoke Detector

At Gunma University in Kiryu, Japan, researchers have demonstrated that the use of an integrating cylinder as a light collector improves the sensitivity and linearity of optical smoke detectors. They reported their findings in the Jan. 1 issue of Applied Optics.

In the experiments, they monitored the transmission of 460-nm light from an LED through a 140-mm-long, 10-mm-diameter cylinder coated with flat interior house paint. Evaporated stearic acid served as a source of smoke. Compared with an LED and photodiode alone, the enhanced system displayed a higher detection sensitivity and better linearity and stability in the output signal.