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IKN-RS-SOP-11: Handling Contamination Meter and Radiation Survey Meter

DOCUMENT NO.   :  IKN-RS-SOP-11

INTRODUCTION

The response of the contamination meters and survey meter should be appropriate according to the type of radiation involved. Only calibrated meters should be used. Confirmation of the calibration can be made by looking at the meter’s certificate of calibration. It is also important to ensure that the meter’s battery is always in good working condition prior to its usage.

 

PURPOSE

To monitor the working area and to ensure the radiation safety of the staff and workplace.

 

RESPONSILIBILITY

  • Radiation Protection Officer (RPO)
  • Physicist
  • Radiation Workers

 

Frequency

Not Applicable (N/A)

 

Equipment

  • Survey Meter
  • Contamination Meter
  • Area Monitor

 

PROCEDURE

Handling the Survey Meter

  1.  Check the calibration validity period of the survey meters. The calibration certificate should be valid before the survey meter is used. Survey meters with expired calibration periods should be sent back to approved calibration centers for re-calibration.
  2. Switch on and wait for the stability.
  3. Check the battery to ensure it is more than 50% of the battery scale.
  4. Check the response of the survey meter against a check source to ensure an expected reading. Report RPO for any abnormal reading.
  5. Switch the survey meter scale to the maximum range (if analogue meter).
  6. Switch on the audible signal.
  7. Measure the background radiation.
  8. Bring the contamination meter or survey meter to the workplace for measurement and switch to a lower scale if there is no response for analogue meter.
  9. The probe protective cover should be removed when measuring beta or low energy x-ray or gamma ray.
  10. Obtain the net reading (Net reading = actual reading – background reading).
  11. If necessary, make an assessment of the measurement results. Multiply the reading of the survey meter with the calibration factor (CF) as recorded in the calibration certificate for accurate survey meter measurement.
  12. Record the data and ensure that the outcome measurement is reasonable compared to the previous measurement results.
  13. Switch off the survey meter once the measurement is completed.

 

Handling the Contamination Meter

  1. Check the test or calibration certificate. Confirm that the last formal test date, test conditions and result are satisfactory. Check the last routine test result.
  2. Assess the potential contaminant radionuclide. Judge whether the instrument is suitable.
  3. Set the instrument’s parameters. Test the battery, adjust the detector voltage and set the zero as necessary. Start multi-range instruments on the minimum.
  4. Obtain a background reading (s–1) at about 1 m from the contaminated surface.
  5.  Obtain a reading from the contaminated surface. At a speed appropriate to the detector’s capabilities, scan the instrument or its probe over the surface at a distance which avoids contact. Hold the detector at the calibration distance (about 0.5 cm) from the contamination to obtain the surface reading.
  6. Calculate the indicated total surface contamination. Subtract the background from the surface reading. Then use the appropriate calibration data to convert the corrected measurement from a count rate to a value of surface contamination (in Bqcm–2).
  7. Assess the result. Decide whether there are any factors which could influence the result such as the curvature of the surface, ‘self-absorption’ of radiation within thick contamination, a wet or uneven surface masking alpha and low energy beta emitters.

 

Handling Area Monitor

  1.  Check the calibration validity period of the area monitor. The calibration certificate should be valid before the area monitor is used.
  2. The area monitoring system shall be functional continuously.
  3. Check the response of the area monitor against a check source to ensure an appropriate reading if necessary.

 

REFERENCES

  1. Atomic Energy Licensing (Basic Safety Radiation Protection) Regulations 2010.
  2. Nuclear Medicine Resource Manual, IAEA 2006.
  3. Radiation Protection in Nuclear Medicine, Radiation Protection Series Publication No. 14.2, ARPANSA 2008.
  4. Applying Radiation Safety Standards In Nuclear Medicine, Safety Reports Series No. 40 IAEA 2005.

 

DISCLAIMER

This Standard Operating Procedure (SOP) was developed based on compilation of best available information, knowledge, field experience, and general practices to provide guidance to IKN staff in performing the activities defined herein, in a consistent and standardised manner.
IKN does not guarantee nor accept any legal liability whatsoever arising from or connected to the accuracy, reliability, currency or completeness of any material contained herein.
IKN shall take no responsibility for and will not be held liable for this document being temporarily unavailable due to technical issues beyond our power and control.