Environmental Science & Research - Calibrations

By: Environmental Science & Research  06-Dec-2011
Keywords: General Information

In this section:

General information

The NRL offers radiation measuring instrument calibration services to a range of customers involved in industry, medicine, and research. 

The facilities maintained at the NRL in support of the calibration service include:

  • primary and secondary standards of radiation exposure
  • a protection level 137Cs exposure facility
  • a therapy level 60Co exposure facility
  • a 10 kV – 300 kV x-ray exposure facility
  • calibrated mammography and general radiography x-ray plants

For further information please contact the Calibrations Team.

The NRL calibration service maintains phantoms and beam set-ups that conform to the requirements of ISO standard 4037.  Using these beams, and data from the standard enables the NRL to deliver irradiations to personal dosemeters for the purpose of calibration in terms of the ICRU operational quantities, HP(0.07) and HP(10).

X-ray beams used for the irradiations have peak voltages in the range 20 kV – 300 kV.  The 662 keV, and 1.25 MeV emissions from 137Cs and 60Co are also available for irradiations. 

The irradiations are traceable to either the NRL primary standards of exposure, or to Australian National Standards of exposure. 

For further information please contact the Calibrations Team.

For clients using diagnostic dosemeters, the NRL offers standard calibration products that suit the following measurement applications: 

  • Dental x-ray machine outputs
  • Mammography x-ray machine outputs
  • CT x-ray machine outputs (flood irradiation of pencil chambers)
  • Patient entrance doses for general radiography, and doserates for fluoroscopy
  • AEC input doses and image intensifier input doserates
  • X-ray tube leakage
  • Patient scatter levels

For clients with measurement applications not covered by the above categories, the NRL will most likely be able to tailor a calibration product that meets your needs.

The calibrations are traceable to either the NRL primary standards of exposure, or to Australian National Standards of exposure.

For further information please contact the Calibrations Team.

The NRL maintains x-ray plants that are representative of the x-ray plants used for general radiography, fluoroscopy, and mammography.  These x-ray plants are used to offer a calibration service for non-invasive kVp meters.  The calibrations offered cover the following uses:

  • Radiography: 50 kVp – 150 kVp
  • Fluoroscopy: 70 kVp – 110 kVp
  • Mammography: 25 kVp – 31 kVp

Calibration of the kVp settings on the x-ray plants used has been performed in terms of peak spectrum energy using high purity germanium detector spectrometry, and is traceable to fundamental physical constants in the form of known radionuclide gamma ray emission energies.

For further information please contact the Calibrations Team.

A 137Cs exposure facility is maintained for the calibration of portable radiation protection survey instruments.  Air kerma rates available for calibration are in the range 4 µGy/hr – 800 µGy/hr.

The following instrument tests can be performed:

  • Calibration of the instrument in rate-mode operation
  • Calibration of the instrument in integrate-mode operation
  • Test of alarm function
  • Test of instrument performance under high doserate conditions

Calibrations are traceable to US National Standards of exposure for 137Cs held by NIST.

For further information please contact the Calibrations Team.

Calibrations for superficial and orthovoltage therapy dosimetry:

Exposure calibrations are provided in the range 15 kV – 300 kV.  Matching to the customer's beam qualities is achieved by providing calibrations at standard qualities that bound the required quality.  The customer can then interpolate on the basis of the beam HVL to obtain the required calibration factor.  Calibrations are traceable to the NRL primary standards of exposure, or to the Australian National Standard of exposure. 

Calibrations for megavoltage therapy dosimetry:

Air kerma calibration factors traceable to the Australian National Standard of exposure for 60Co can be provided for all chamber types.  Absorbed dose to water calibrations suitable for use with the absorbed dose to water dosimetry protocol TRS398 can be provided for NE2571 (or equivalent) chambers.  Absorbed dose to water calibrations are traceable to the Australian National Standard of absorbed dose to water for 60Co.

Note that for ease of transport, the NRL does not require a constancy check source to accompany therapy dosemeters for calibration.  The NRL suggests that customers perform constancy checks to confirm consistent response of the instrument prior and subsequent to the calibration at the NRL.

For further information please contact the Calibrations Team.

Keywords: General Information

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