· Sensitivity: The radiation emission of spark will be measured in Wafts. The sensitivity of the detector will be measured in Wafts per square centimeter required to trigger the detector. This definition is still too general as there is a specific response involved in the triggering of the detector and a specific optical range in which the detector is sensitive.
The definition of sensitivity, in accordance with the current NFPA standards, is: The sensitivity of a detector is the wattage per square centimeter incident on the photosensitive surface of the detector from a radiating source, whose optical range lies within that of the sensitivity range of the detector, which will trigger the alarm after the given response time.
· Response Time: The response time is the time between the reception of the optical signal to the transmission of the alarm signal from the detector head.
· Angular Acceptance: The angular acceptance is a measure of the response of the detector as a function of the angle. As the angle of acceptance increases, the probability of detecting a spark increases. Furthermore, a large angle of acceptance reduces the amount of detectors necessary for an application. We designed the detector in order achieve the highest possible angular acceptance with a flat photo diode.
· Half Power Cone of Vision (HPCV): The half power cone of vision, or HPCV, is a measure of the angle at which the sensitivity of the detector is decreased by half. As an installation requirement, we suggest that the entire duct is within the HPCV of at least one detector.
· Spectral Response: As stated earlier, the spectral response is the sensitivity of the detector as a function of the wavelength. A silicon photodiode which is sensitive from 0.4 to 1.1 microns. This is a range from the optical (green) to the near infra red.
·
·