Continuously Recording Field Monitor for Krypton-85

Krypton-85 from nuclear power generation is released to the atmosphere mainly during fuel reprocessing. The monitor described here is designed for use in the vicinity of these facilities. It is battery operated, resistant to weather exposure, and portable. Sensitivity has been verified in the field as 10-20 pCi/liter. The detector array uses two pairs of betasensitive dual window pancake GM tubes. One pair is shielded so that it provides a response to gamma photons only. The output of the two channels is stored on a computer-compatible serial magnetic cassette recorder.