How to read the certificates

The Accredia certifications are documents that attest calibration and state the margin or error of the instruments for the control and detection of radioactive sources in objects, environments and persons.

The Accredia calibration certificate is divided into three parts: the opening, standard for all Accredia certifications, the section with data and results of instrument calibration and, in conclusion, a brief report regarding the calibration operation.

The number of the Calibration Certificate, unmistakable reference to the certificate issued, is given on every page, immediately after the heading. The Calibration certificate number is useful if contacting the Comecer Centre for information regarding the certificate or the instrument.

Data and introduction

On the first page of the certificate, find data relative to the company, instrument and date of calibration. In particular, the date of issue of the certificate is useful for planning the next calibration. Normally, the Comecer Calibration Centre recommends calibration of instruments once a year.

As well as the date of issue, the request code is also indicated, which refers to the estimate requested forwarded. The request code is useful as an identification number of calibration that has been performed and allows the Comecer Centre to recall the data and the details of the relative instrument, the calibration and customer’s company.

Calibration report

The second page gives the measurements made by the Comecer Centre in order to detect the calibration factor of the instrument. Every instrument is identified according to the manufacturer of the same and the sensor analysed (the manufacturers can differ).

The table is divided as follows:

• Beam code: it is the code of the radiation or source (for the detail of every code, consult the Table of reference beams)
• En. average reference radiation: indicates the average energy of the radiation emitted in kilo electron volts
• Reference value: they are the reference quantity values and their unit of measurement, expressed in reference environmental conditions (specified in the certificate)
• Calibration factor F (Reference value/Reading value): factor to multiply by the value read by the instrument to obtain the reference value
• Instrument reading value: value read by the instrument in the calibration phase. The nearer to the KERMA RATE reference value, the more precise the instrument.
• High-full scale: indicated only for particular types of instrument with switch
• Dimensionless calibration factor: factor to multiply by the value read by the instrument to obtain the correct measurement
• Percentage extended uncertainty on F: percentage of uncertainty of the calibration factors F and dimensionless
• Procedure code: procedure number within the Comecer Calibration Centre, it has legal value.

Following issue of the certificate, every time a detection is made using the instrument, the operator must multiply the value measured by the dimensionless calibration factor.

Details and comments

The last page indicates the execution method of the calibration, where the procedure used is explained along with any comments that can include specific observations or recommendations for using the instrument. The environmental conditions of irradiation of the detector are stated to close the document, accompanied by a diagram to illustrate the position of the instrument with respect to the source during irradiation.