5. Measurements with the Piranha System
Dental and Panoramic Dental
Piranha & QABrowser Reference Manual
2014-06/5.5C
130
The Piranha now first analyses the beam and displays the type of waveform. This is
done once. Then the estimated total filtration is displayed.
Read the measured values from the display.
6. Repeat the measurement for other generator settings or select an application to
measure further.
5.6.2 Waveforms
The example below explains why a change of delay change the value of measured kVp
and the kV and radiation waveform on a one phase dental unit.
From the study of the above three screens several conclusions can be made:
1. A stable output level is not reached until after approximately 200 to 300 ms (20 to 30
pulses for a 50 Hz main based dental unit).
2. The exposure time is depending on the definition of the trig level.
3. The kVp value in the RTD is related to selected delay and window and is several kV
higher in the beginning of the exposure at the same time as the radiation level is
relative low here. Therefore a delay of 200 ms is default for the Piranha.
If the signal to the detector is too low to give a correct kV value, this part of
the waveform will be blank. This is the reason why only the upper parts of
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