NDS - Laboratory for Dosimetry Standards

The main interrelated activities of the NDS laboratory are the calibration of ionising radiation instruments and the maintenance of a secondary reference standard in the field of dosimetric quantities (air kerma) and in the field of radiation protection quantities (dose equivalents, surface emission).

In the NDS laboratory, calibrations and irradiations of (active and passive) dose and dose rate meters (γ-radiation and X-radiation) and calibrations of contamination meters (surface emission of α and β particles) ensure the dissemination of metrological traceability at national and international level.

For calibrations and irradiations, please contact the directly.

We calibrate and irradiate all types of radiation protection instruments:

• portable dose (rate) meters (ambient dose equivalent H*(10), air kerma Ka) (Fig. 1)
• dose meters (e.g. electronic dosimeters, passive dosimeters) (personal dose equivalents Hp(10) and Hp(0,07)) (Fig. 2)
• ionisation chambers (Fig. 3)
• surface contamination meters (Fig. 4)

 

Fig. 1 Dose rate meter

Fig. 2 Personal electronic dosimeter (right) and personal passive dosimeter (left)

Fig. 3 Ionisation chamber

Fig. 4 Surface contamination meter

 

The following resources are available for calibrations of γ-ray and X-ray radiation meters:

Cs-137, Co-60, Am-241 and N-series X-ray spectra (N-20 to N-300)

according to ISO 4037:2019 (parts -1 to -4), X and gamma reference radiations for calibrating dosemeters and doserate meters and for determining their response as a function of photon energy

X-ray spectra of the RQR, RQA and RQT series (RQR/RQA-3 , RQR/RQA-5, RQR/RQA-7, RQR/RQA-8, RQR/RQA-9 and RQT-8, RQT-9, RQT-10)

and the X-ray spectra of the mammography series RQR-M and RQA-M (RQR/RQA-M1 , RQR/RQA-M2 , RQR/RQA-M3 , RQR/RQA-M4)

in accordance with CEI/IEC 61267:2005, Medical diagnostic equipment - Radiation conditions for use in determination of characteristics.

Sl. 5 Cs/Co irradiator

Fig. 6 Am irradiator

Fig. 7 Comet X-ray machine

Fig. 8 Seifert X-ray machine

 

The following area sources are available for calibration of surface contamination meters:

• α radiation sources: Am-241, U-238
• β radiation sources: C-14, Cl-36, Sr-90, Cs-137, Tc-99

both according to the infinite area source method of NPL GPG No 14

Fig. 9 Area sources

 

Our calibration and measurement capabilities (CMC) are published in the Key Comparison DataBase (KCDB) of the BIPM. All data are publicly available on the BIPM website.

The traceability of the kerma and dose equivalent standards is ensured indirectly by secondary ionisation chambers (Fig. 10), and the traceability of the surface emission standard is ensured directly by calibration of the area sources in the primary laboratories (Fig. 11).

Fig. 10 Secondary ionisation chambers:

• (top) LS 01: traceability of Cs-137, Co-60, Am-241 and N-series X-ray quality sources;
• (bottom left) TW 34060: traceability of RQR, RQA and RQT diagnostic spectra
• (bottom right) RC06M: traceability of RQR-M and RQA-M diagnostic spectra and N-20 to N-60 series X-ray qualities

Fig. 11 Area sources with an active area of 10 x 10 cm² for calibration of surface contamination meters

 

Ionisation chambers and area sources are periodically sent for calibration to the primary laboratories or to a secondary IAEA laboratory traceable to the primary laboratories.

 

 

• High-activity sealed sources (HASS): Cs-137, Am-241
• Sealed gamma source: Co-60
• X-ray system 1: 15–320 keV (ISO 4037 narrow spectra (N), IEC 61267 diagnostic spectra: RQR, RQA, RQT)
• X-ray system 2: 2–60 keV (IEC 61267 mammographic diagnostic spectra: RQR-M, RQA-M)
• α radiation: Am-241, U-238
• β radiation: C-14, Cl-36, Sr-90, Cs-137, Tc-99

 

Dose rate range:  

• 0–0,18 Gy/min
• 0–0,1 Sv/h

Dose range:

• 0–10 Gy
• 0–10 Sv

 

Gamma and X-ray energy ranges: 10–1250 keV

Duration of irradiation: up to 16 hours as standard, up to 60 days with intermittent irradiations

Range of variation of radiation intensity: up to 107 (different qualities), up to 105 (Cs-137)

Distance between the radiation source and the isntrument: up to 7 m

Main use of the laboratory: calibrations, irradiations, testing, research

 

Dosimetric quantities:

• Air kerma[Gy]
• Ambient dose equivalent H*(10), personal dose equivalent Hp(10) and Hp(0,07) [Sv]
• Surface emission: α, β [s⁻¹]

National

• Maintaining the traceability of a reference standard - Ionizing radiation
• Calibrations

 

International

• Calibrations