Re: Gy and Sv = J/kg

[JMUCKERHEIDE@delphi.com]

Hi Dave,

I agree. Well said. Note that a 'bookkeeping' quantity would affect units. Add 
that a well-founded bookkeeping quantity would be well-founded and replicable
rather than widely different values in different studies/conditions. 

> 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.

Agree in principle, but the values fail in practice, except as an
administrative regulatory value with no scientific foundation for neither the
physical effects nor values being applied. This would be fine if stated that
way, and open for scientific development, but the problem that is being
considered here, is that the quantities are being treated as physically valid
quantities and scientific work/consideration closed off. (See eg, Vic Bond's
treatment, and many others, by the closed process of the rad protection policy 
boards.)  

> 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.

True as far as its "definition" reflects a desired concept/result; but not
true when the concept has failed and no sound result can be established. 

> 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.

Amen :-)
 
> Dave Scherer
> scherer@uiuc.edu

Thanks.

Regards, Jim Muckerheide
jmuckerheide@delphi.com