Re: Gy and Sv = J/kg

[David Scherer <scherer@uiuc.edu>]

It seems to me that dose equivalent was never intended to be a physical
quantity.  IMHO, it is a bookkeeping quantity.  As an operational HP, I am
glad I don't have to keep separate records of gamma dose, beta dose, alpha
dose, thremal neutron dose, epithermal neutron dose, etc.  And I'm happier
still I don't have to make some kind of independent judgement about how to
combine these doses to decide whether a worker has received too much.

The concept of dose equivalent (whatever the unit) has been misused, e.g. as
an index of risk in epidemiology.  (In fact the epidemiology should be used
to determine the Q or w-sub-R, not the other way around.)  This is an error
in the concept's application, not its definition.

Aside: Equivalent dose is another bookkeeping device that has been similarly
misused.  And the uncertainties in w-sub-T make w-sub-R look like a clean
measurement.

Dave Scherer
scherer@uiuc.edu