Re: Beta dose from cloud

[Bob Flood <bflood@SLAC.Stanford.EDU>]

At 01:52 PM 1/16/97 -0600, you wrote:
>I do not have reg guide 1.4 but there is supposed to be a formula	
>in it for beta dose to the skin from a cloud.  I have some questions	
>along with this.  Is the formula D(B)=0.23EC where the E is the average	
>energy, and C is the concentration in Ci/meter cubed ?  Can I use this	
>with a DAC Value for an  isotope, which is in Ci/meter cubed, for the 
>concentration limit, to consider dose rates at a stack or outlet to a	
>facility or lab for setting alarm rates?  For example if I wanted to set
>an alarm rate meter in mr/hr, and I was concerned with external radiation
>exposure, like in the case of Ar-41 exposure.  Am I way off base here?
>

I recommend ICRP-30. It contains submersion dose rate factors for various
isotopes, and includes factors for semi-infinite and finite geometries,
which may prove very useful.

The approach is valid. One can set an alarm for a dose rate meter based on
the calculated dose rate from a concentration. And that's where the finite
geometry data may be useful - use of factors for semi-infinte cloud
geometry could lead to very conservative alarm settings.

Be aware that the factors relating the airborne concentration to dose rate
will not always be for skin dose. The factors will apply to the dose that
is limiting. In some cases, depending on the mix of radiations emitted, the
skin dose limit may be reached before any other, but in other cases, the
whole body or effective dose equivalent limit may be reached before the
skin limit.


Bob Flood
Stanford Linear Accelerator Center
(415) 926-3793     bflood@slac.stanford.edu
Unless otherwise noted, all opinions are mine alone.