Samuel Held has asked how we assure that minors (students under 18
years old) do not receive an illegal radiation dose. Do we have
monitors? Do we use film badges?
We do a calculation. Our x-ray spectrometer emissions are measured
biannually by the Ohio Department of Health. It actually radiates no
detectable radiation above background. So we know that no student will
receive an illegal dose from that.
Our radioactive materials are all license exempt sources and they are
all marked with their maximum activity (at the time of purchase). We
can do a worst-case calculation of the radiation dose if a student
holds such a source close to his body for the whole lab period. If
this calculation gives a lower dose than the maximum permitted by law,
we know the typical working situation will be even less than that.
In Ohio this calculation is sufficient if it shows the students are not
likely to receive a dose greater than a specified level. For example,
students under 18 years old are not allowed to receive a dose greater
than 10% of what an adult can receive. However, if we can demonstrate
(via calculation) that the minor student will not receive a dose
greater than 5% of an adult dose, then monitoring is not necessary.
The Ohio law specifically says that personal monitoring equipment is
required for "each individual under 18 years of age who enters a
restricted area under such circumstances that he receives, or is likely
to receive, a dose in any calendar quarter in excess of 5 percent of
the applicable value specified in...[a table]."
So we show, by a convincing calculation, that minor students cannot
receive a dose in excess of 5% of the adult limit, and we are legal and
also in a situation that does not require personal monitoring.
We do tell students that if they are pregnant or think they might be
pregnant that they can be excused from performing the experiment.
Whether they would admit to this is certainly a question we can wonder
about. But we do make the statement.
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817