AND MEASUREMENT OF RADIOACTIVITY
reading this section you will be able to do the following:
how we detect radioactivity/radiation and name the instrument
that is used.
- List some
safety precautions and explain their importance.
Although some forms of electromagnetic
energy, such as light and heat, can be detected by the human senses.
One of the greatest draw backs to high energy radiation is the
inability to detect it. We cannot see, feel, taste, smell, or
hear the various forms of ionizing radiation. Fortunately, ionizing
radiation interacts with matter which makes detection and measurement
possible by utilizing specialized equipment. In this section we
want to introduce you to the various ways and means of detecting
and measuring ionizing radiation.
As mentioned previously, Becquerel
discovered radioactivity because it left marks on photographic
film as a means of detecting radiation. However, there are more
definitive means commonly used by scientists and technicians who
study and work with radiation. The equipment utilized for the
detection and measurement of radiation commonly employs some type
of a substance or material that responds to radiation. Many common
methods use either an ionization process or molecular excitation
process as a basis. Remember that we stated earlier that radiation
interacts with matter. For detection and measurement purposes
the process of ionization is the most commonly employed technique,
based on the principle of charged particles producing ion pairs
by direct interaction. These charged particles may collide with
electrons, which removes them from their parent atoms, or transfer
energy to an electron by interaction of electric fields.
How do you
choose a detection device?
Important considerations for choosing
a particular type of detection device include the application,
the type of radiation, the energy of the radiation, and the level
of sensitivity needed. Remember from previous discussion that
radiation exists as waveforms with varying energies and may be
either particulate or electromagnetic in nature.
- Take the following links to learn
about different detection devices:
Some of the principle safety precautions
commonly used in working with radioactivity/radiation are time,
distance, and shielding. Recall our earlier discussion of the
dentist wanting to photograph your teeth. Have you ever wondered
why the dentist lays a heavy apron across your chest? The dentist
is practicing a means of protection from exposure. In that, they
are using distance and shielding from the source of radiation.
The concepts of these three principles are fairly simple. The
first principle is time. The less time you spend around a radioactive
material the less exposure you will receive. The second principle
states that the greater the distance away from a radioactive source
the lesser your exposure to the radiation. Lastly, if you can
protect yourself with some type of material to act as a shielding
device you will also reduce your overall exposure.
that measure ionization are the most commonly used instruments
for detecting radiation.
important words to help you minimize your exposure to radiation
are time, distance, and shielding.