The system of personal nuclear accident dosimetry of photon or mixed neutron plus gamma radiation

An accurate, simple and reliable system of neutron or gamma radiation personal dosimetry for nuclear accidents is developed based on the commercial emergency dosimeter DL-M4 which is tissue equivalent for photon or mixed (n+gamma) radiation fields of all practically important energy spectra. The DL-M4 dosimeter measures neutron plus gamma total tissue absorbed dose directly. The pencil of the dosimeter may contain a chip (1 mm O.D. x 4 mm) of 7LiF or other neutron insensitive thermoluminescent material for separate measurement of the gamma component of total dose. The addition of 6LiF (or natural LiF) would help to measure neutron albedo which can indirectly give sufficient information in the low neutron or gamma dose range not measurable by DL-M4. Two such dosimeter sets carried on opposite sides of the body will accurately and immediately measure the maximum surface dose. Some additional sets can give the minimum dose too, which allows the approximate determination of organ doses and the precise enough forecast of radiation damage to the irradiated person. In the 1 to 10 Gy dose range the DL-M4 alone (maximum and minimum total doses) gives enough information for quick protective actions. (author)