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5 years ago

Applying the pulsed ion chamber methodology to full range reactor ...

Applying the pulsed ion chamber methodology to full range reactor ...

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other system yet developed offers the required sensitivity in conjunction with the necessary gamma discrimination that they do. Counting systems, when stretched to their limits, cove?' only half of the twelve decade range. fhe intermediate range instrumentation covers most of the remaining six decodes, overlapping two to four decades of the source range and pert or all of the power range. The sensors used to spun this range are ion- ization chambers of various designs with boron or fissile electrode coat- ings. When simple fission (or boron) chambers are used, the associated signal processing circuitry is designed so that the resulting system's output is some measure of the mean square voltage (mean of the squares of the deviation from the mean), abbreviated MSV. Since Poisson statistics govern the pulses from a nuclear radiation sensor, a measure of the mean square voltage is a direct measure of the mean counting rate. This method has just recently been developed and offers at least three impor- tant advantages over the conventional compensated ionization chambers:" increased gamma discrimination (100 times more than the CIC) , improved operation when chambers and cables are exposed to elevated temperatures, ?in