Ronan X96S MOLD LEVEL GAGE - Manual (Page 6)

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Theory
Theory of Radiation Gaging
Radiation gages operate on the principle of radiation absorption and transmission.
A beam of gamma radiation is directed from the source holder, through the vessel and its process material, and onto the surface of
the detector.
Radiation which is not absorbed by the material through which it passes, is transmitted to the surface of the detector.
Process measurement is possible because the amount of radiation absorbed and transmitted is predictable.
The absorbed radiation is directly related to the level of process material in the vessel while the transmitted radiation is inversely
related to the level of process material in the vessel.
Therefore, an increased process level results in a decrease of transmitted radiation.
Since the radiation that's not being absorbed is being transmitted, the process level can be inferred by measuring the amount of
radiation reaching the detector at any point in time. The detector's output signal, in counts, also varies inversely to the process
level.
When the process level is low the detector is exposed to a maximum amount of radiation which produces a HIGH output of
counts. When the process level is high the process material "shields" the detector and prevents radiation from reaching the
detector, producing a LOW output of counts.
The X96S Microprocessor converts the detector signal to user's measurement units of level: m, mm, cm, in, ft.
The X96S displays the output measurement range in the selected user units. The "zero" of the measurement range represents the
lowest level of interest, while the "span" of the measurement range represents the highest level of interest.
Reduction of the signal "noise" due to radiation statistics is handled in the stage of signal processing known as digital filtering.
Digital filtering is a form of statistical averaging used to smooth, or dampen, random radiation as well as process-related noise.
Increasing the digital filter’s “time constant” decreases signal noise.
Dynamic tracking permits the gage response to temporarily by-pass the digital filter. This is helpful in some processes where
sudden or drastic step changes in process must be observed in their true, or unfiltered, state.
Software also compensates for the decay of the radioactive source activity. On-going adjustments are made automatically for the
rate of decay, or source half-life.