Observation of light from resistive plate chambers

Electrically induced signals and light emissions from Restrictive Plate Chamber (RPC) are simultaneously measured using a glass RPC with transparent high-voltage planes, operating in the streamer mode. With one exception, good correspondence is seen in between the electrical and optical signals in every aspect: signal shapes, pulse heights, timing and afterpulses. The one exception is a possible limiting effect observed on the optical signal pulse height for a given pulse height of electrically induced signal. Shapes of the signal visually observed by eye are also described.