RE: Cobalt-60 dose

[Glen.Vickers@ucm.com]

I didn't recall that the original post specified the geometry?...

There is also often times a difference between calculated and measured dose
rates.  Energy dependencies, ion chamber vs. GM (pulse counter), etc.

Sincerely,
Glen Vickers
glen.vickers@ucm.com

> -----Original Message-----
> From:	Luketina, Ivan [SMTP:ivan.luketina@cit.ac.nz]
> Sent:	Tuesday, October 19, 1999 3:48 PM
> To:	Multiple recipients of list
> Subject:	RE:Cobalt-60 dose
> 
> Not having seen tables of SI values I have puzzled over the conversion of
> the air kerma constant to SI units and came up with the following:
> 
> If the specific gamma ray constant for Co-60 is 13.2 R/mCi-hr at 1 cm from
> another posting then the conversion is from units of (R.cm^2)/(mCi.h) to
> (microGy.m^2)/(GBq.h)
> 
> Using the air kerma K (Gy) = 0.00876 x exposure (R)
> or   K (microGy) = 8760 x exposure (R)
> 
> 1 cm^2 = 10^-4 m^2
> 
> 1 mCi  =  3.7 x 10^7 Bq = 0.037 GBq
> 
> then the conversion factor becomes (8760 x 10^-4)/0.037 = 23.68 
> 
> and 13.2  (R.cm^2)/(mCi.h)  = 313 (microGy.m^2)/(GBq.h)
> 
> Perhaps someone with a table of SI values could confirm the 350
> µSv.m²/(h.GBq) value or the accuracy of the above.
> 
> 
> Ivan Luketina
> Ivan.Luketina@cit.ac.nz
> 
> 
> From:	Herwig Mandl <H.Mandl@lkasbg.gv.at <mailto:H.Mandl@lkasbg.gv.at> >
> To:	"'radsafe@romulus.ehs.uiuc.edu'" <radsafe@romulus.ehs.uiuc.edu
> <mailto:radsafe@romulus.ehs.uiuc.edu> >
> Subject:	AW: Cobalt-60 dose
> 	Message-ID: <01BF1A15.2B7DBFC0@C1MM080.lkasbg.gv.at
> <01BF1A15.2B7DBFC0@C1MM080.lkasbg.gv.at">mailto:01BF1A15.2B7DBFC0@C1MM080.lkasbg.gv.at> >
> 
> 
> Doserateconstant for Co-60: 350 µSv.m²/(h.GBq).
> Use SI-Units!
> Herwig from Salzburg
> 
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