Working with ionising radiation: Sealed sources

Sealed sources have been constructed so that the radioactive material they contain cannot be dispersed. This usually means that the material is sealed in some sort of source container - e.g. a plastic / resin laminate (small teaching sources), a welded stainless steel container (some larger activity sources), a metal foil construction (some instrument sources).

All sealed sources are controlled by the university and certain protocols should be followed when handling such sources or the equipment they are installed in.

Key risks

  • Failure to follow operating protocols and thereby increasing the radiation exposure or compromising the sealed source;

  • Misuse of sealed sources resulting in dispersal of radioactive material;

  • Theft or loss of sources which could put the public at risk.

What you need to do

  • Follow the New Users instructions to complete any necessary registration and training requirements.

  • Most uses of sealed sources do not require you to register as a radiation worker but check with your Radiation Safety Coordinator (RSC).

  • You need the authorisation of the University's Radiation Protection Manager before acquiring, moving or disposing of any sealed source.

  • The Radiation Protection Manager will carry out an inspection of sources, instruments and applications before they are first used to ensure that radiation doses are minimised.

  • You must follow the Standard Operating Procedure (SOP) for the source you are using.

There are three main applications for sealed sources in the university: instrument sources, liquid scintillation counters, and teaching sources and each of these applications has its own Standard Operating Procedure (SOP) - see 'Related downloads' at the bottom of this page.

Instrument sources

  • keep these sources safely enclosed within the instrument and follow the manufacturer's guidelines when using them. This will make sure that radiation doses are kept to a minimum.

  • In order to minimise radiation exposure if fitting or removing a source it should be handled for as little time as possible and indirectly (i.e. using forceps) where appropriate.

  • store instruments and sources securely in an authorised storage room.

Liquid scintillation counters

Liquid scintillation counters each contain a 'standard' - a sample of radioactive material used in the counting process.

  • Internal standards will have been installed by the manufacturer and should not be removed or modified.

  • External standards should only be used according to the manufacturer's guidelines. These should also be stored securely in an authorised storage room.

Teaching sources

  • only use teaching sources for specific demonstrations in authorised locations.

  • sources should not be left unattended and should be stored securely in an authorised storage room.

  • Handle sources indirectly (i.e. using forceps) and as for as little time as possible.

Risk assessments

You will not be required to complete a risk assessment of your own before handling sealed sources. However, you should read the risk assessment that matches the source you will be using - see 'Related downloads' at the bottom of this page.

Contact the Radiation Protection Manager if you need more guidance or advice.