BALLISTIC JOULE METER FOR MEASURING A PULSE OF INFRARED RADIATION

摘要

There is disclosed a ballistic joule meter containing an absorber having a sufficiently low absorption factor that energy is transmitted beyond the face of the absorber and is absorbed throughout the volume thereof. The temperature rise due to the absorption of the pulse of radiation is measured by a thin wire electrical resistance thermometer. In order to cancel out ambient effects a reference absorber is also provided in the apparatus which is not exposed to the incident radiation and the energy is measured by measuring the temperature difference between the reference and operative absorber the temperature difference being measured with a bridge circuit.