Calibration of measuring instruments is the process of checking the reading of a measuring instrument to determine the relationship between the reading of the instrument and the known value of the quantity to be measured.
The importance of calibrating radiation measurement equipment
Calibration of radiometers is important for several reasons:
- Ensures dimensional accuracy. Calibration links the reading of the device to the reference value of the corresponding quantity, reduces systematic errors and ensures that measured doses and dose rates are reliable.
- Supports radiation safety. Accurately calibrated equipment will help to correctly assess radiation doses to workers and the general public, and thus avoid under- and overestimation of risks.
- Confirms the condition of the equipment. Regular calibration is also a functional check - it helps to detect sensor obsolescence, electronic faults or incorrect settings before they start to have a significant impact on measurement results.
- Ensures traceability and compliance. Measurement results obtained with correctly calibrated instrumentation are traceable to international standards and meet the requirements of the IAEA and national regulatory authorities.
- Supports quality management. A regular calibration programme is part of a quality system that helps to ensure that all radiation measurements are technically correct and comparable over time and between different instruments.
Frequency of calibration of measuring instruments
The frequency of calibration of measuring instruments depends on the type of measuring instrument, the field of application and the requirements of the manufacturer or legislation. In general, instruments should be calibrated in the following cases:
- At regular intervals, for example once a year or according to the manufacturer's instructions.
- After a repair or adjustment, to check that the device is working correctly.
- Before important measurements or tests, especially when the accuracy of the results is critical.
- If there is any doubt about the accuracy of the instrument, for example, if the measurement results differ from normal.
- Calibration is required by legislation or standards in certain areas (e.g. health, environmental monitoring, food or pharmaceutical industry) at certain intervals. The obligation to calibrate radiometric equipment is often laid down in the licence of the holder of the activity.
How is measuring equipment calibrated?
Calibration of measuring instruments means comparing the reading of an instrument with an accurate with reference, to check its accuracy. The process starts by preparing the equipment and getting it ready for operation. Measurements are then taken with both the instrument to be calibrated and the reference and the results are compared, highlighting any deviation from the reference value. All results are recorded on the calibration certificate, where the calibration factors of the instrument are calculated. The reading of the instrument corrected by the calibration factors ensures the reliability and traceability of the measurement results. Calibrations are usually performed in accredited laboratories, where international standards are followed. This ensures that measurements are accurate and the instrument can be used with confidence.
Our new calibration centre is unique in Estonia. From 2026, the plan is to offer electronic personal dosimetry, dose rate measurement, ionisation chamber calibration and thermoluminescence dosimetry irradiation services. If you are interested in calibration services for measuring instruments, please contact us at partel.saluvere@alara.ee.
