Measuring assemblies

Dosimeters and whole-body radiation meters

These instruments, used to measure ionising radiation, can have an integrated sensor or be composed by electronics (electrometer), which can be connected to various external probes.

The various types of probes can be used inside the whole-body radiation meters and externally.

The types of probes most commonly used in the ionising radiation measuring sector are called as follows:

• Ionisation chamber – high response linearity on the variation of energy and the intensity of radiation are indicated to measure exposure quantity, kerma in air and dose equivalent
• Geiger - reduced response linearity on variation of energy and the intensity of the radiation. Used for the measurements that can be made using the ionisation chambers, but also for the measurement of the quantity of activity.
• Scintillator - reduced response linearity in energy, they are mainly used for low intensity measurements of kerma in air quantity and the quantity of activity
• Photodiodes - little response linearity to energy. They are used in the construction of multimeters used for quality controls of the radiogenic machines relative to the measurements of the kerma in air quantity, kilovolts and time.

Use ambits

The measurement assemblies are used in various fields, from medicine to industry, in general, wherever it is necessary to measure ionising radiation.

Calibration and certification

The Comecer Calibration Centre calibrates the instruments stated above using reference beams X of the radioactive sources in compliance with ISO 4037, BIPM 1972, IEC 61267 Standards.

The verification of the instrument takes place with the issue of the calibration certificate, which states the corrective factor to apply to the instrument.

Recommended times

If a clear document relative to the frequency of calibration has not yet been issued, Comecer recommends the following scheme:

• Whole-body radiation meters , Multimeters and Contamination meters: yearly or every two years if the instrument is not used often (not more than twice a month) or if similar instruments are owned, in a way to calibrate them alternately.
• Hands, Feet and Clothing and Dose calibrators: yearly at a calibration centre and more frequently at the use centre.