SI-units for radiation and activity -Reply

[Charles Willis <CAW@nrc.gov>]

Dear Ing,

We understand the European frustration  about Americans continuing to use
practical radiation units, rather than the SI units.  There is little doubt that
Europeans would not have changed if it were not for (treaty-based?)  compulsion. 
As a teacher, I must use both systems because the existing literature largely is in
practical units and the new literature largely is in SI units.  I expect students to use
whichever units are most convenient for the problem at hand.  I also expect
students to recognize the unending change in the units.  The basic principle is that
when a unit becomes familiar to, and understood by, the bulk of the community, that
unit must be changed.  To the best of our ability we resist this practice, but with
little success.

It should be noted that Americans are not alone in the use of practical units.  In
most international meetings I find Russians and other non-Europeans using
practical units.

Even the folk who strongly advocate SI units tend to have trouble with the practice.
Even the Radiation Dosimetry Journal finds itself using the totally non-SI unit of
time that we have become accustomed to, viz. the "year."   It will be hard to break
the accountants of this serious offense.  Besides, there are public relations
problems: buying whiskey by the cubic meter is one thing, paying taxes by the
second is something else.

Charlie Willis
caw@nrc.gov