No activity is absolutely safe, The risk associated
with collecting radioactive minerals can be greatly
reduced by taking the simple, sensible precautions
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
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
Keep your collection in a cabinet, preferably a
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
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
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.