| 摘要 |
A radiation measurement apparatus and method extends the measurement range of a single Geiger Mueller tube (GMT). The apparatus may operate in a either a conventional mode, used to measure low radiation levels, e.g. background radiation, or an extended range geiger (ERG) mode, used to measure high radiation levels. Both modes utilize the same GMT and basic operating circuitry, including a power supply for generating a GMT anode voltage, a GMT anode voltage control circuit, a GMT trigger circuit, a clock circuit, and a GMT pulse counter circuit. In the conventional mode, the radiation rate is determined as a function of the number of GMT pulses counted over a prescribed time period. In the ERG mode, an additional counter is employed to count trial intervals of a prescribed duration. The radiation rate is determined in the ERG mode statistically as a function of the ratio of the GMT pulse count and the trial interval count, with a prescribed number of trial interval counts being rejected after each GMT pulse in order to assure known initial conditions.
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