7.5.1 Calibration / verification of the instruments
| Measurement instruments, whenever feasible, must be periodically sent for calibration. It is recommended to use at least one instrument having calibration made by an accredited laboratory. The measurements obtained with other instruments can be re-scaled to the values of the calibrated instrument. |  |
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In the case of using different devices in a measurement campaign, it is always advisable to compare the readings among the different instruments at locations where different dose rate levels are found. Differences not exceeding 25 % of relative bias can be re-scaled to those of the instrument selected for reference. |