Sensible Precautions

No activity is absolutely safe, The risk associated with collecting radioactive minerals can be greatly reduced by taking the simple, sensible precautions listed below:-

• Invest in a Geiger counter, learn how to use it properly, and use it regularly to check radiation levels around your collection.
• In the UK safety is controlled by the Health and Safety Executive (HSE). Visit their website at www.hse.gov.uk/radiation/ionising/doses  to learn more about radiation. The currently recommended maximum doses are specified in the Ionising Radiation Regulation 1999 (IRR99). For members of the general public the limit is 1 milli-Sievert/calendar year (100milli-rad/calendar year).

  Note: as knowledge is accumulated, the recommended safety levels may change.

• World-wide the average background radiation level is 2.85 milli-Sieverts/calendar year of which 2.0 milli-Sieverts is due to Radon gas that accumulates in cellars, mines etc. We have no control over this radiation other than to avoid obvious 'hot-spots'.
• When buying a Geiger counter, check the instrument range to be sure that it reads accurately at micro-Sievert level.
  

  Note:The meter reading will then enable you to calculate how many hours per year you can safely be exposed to the measured radiation level.

• Choose smaller specimens. These frequently have finer crystals and smaller specimens will reduce the total amount of radiation.
• Place individual specimens in closed cases whenever possible.
• Keep your collection in a cabinet, preferably a steel one.
• Do not store radioactive specimens in frequently occupied living rooms, especially any that may contain food or drink.
• If possible store the collection in a separate building such as a shed or garage remote from the house. A brick building affords better shielding than a wooden one.
• Make sure that the building is well ventilated.
• Ensure that the collection is kept clean and dust-free.
• Limit the time spent examining your specimens. The measured radiation levels from your collection will determine the maximum number of hours per year that you can safely be exposed to the radiation. If you want to study your specimens in detail, why not photograph them?

Most importantly of all,

• Take great care not to inhale or ingest dust from the specimen or its case. Internal organs cannot be protected against the most damaging form of radiation, alpha particles. Dead skin or a sheet of paper will protect against external sources.
• For the same reason, do not handle specimens when you have cuts or broken skin.
• Thoroughly wash your hands after handling specimens

The different radiation threats

• Radiation is effecively distributed uniformly over the surface of a sphere having the source at its centre. Intensity decreases very rapidly as the inverse square of the distance from source. So avoid getting too close to your specimens.
• Alpha particles travel only a few inches in air and can be stopped by a sheet of paper or skin. However, alpha particles will penetrate the epithelium that covers internal organs. The greatest threat from alpha particles is therefore material entering the body through ingestion, cuts, open wounds etc. Cleanliness (avoiding dust) is your best protection.
• Beta particles will travel several inches in air before being 'captured' but can be stopped by a sheet of aluminium, thick clothing etc. The better quality Geiger counters will have a thin wall that allows beta particle radiation to be measured.
• Gamma radiation poses by far the greatest threat. Being pure electomagnetic radiation it has no potential energy to dissipate and can only be stopped by several inches of lead; but intensity decreases with the square of the distance from the source. A good Geiger counter is therefore your best protection. It should come with a calibration against a known source, e.g.Cesium-137. Its measurement of micro-Sieverts/hour (milli-rads/hour) will deteremine how many hours per year you can safely study your specimens without exceeding the HSE recommended maximum dose.