Re: Old Activity Units?

[Michael Kay <mikekay@teleport.com>]

Ron L. Kathren wrote:
> 
> As an old timer, I would suspect that MC is actually written in lower case
> (ie mc) and means millicurie; the ancient abbreviation for curie was c
> before it was changed to Ci to avoid confusion with the symbol for the speed
> of light.
> 
> Ron Kathren
> 
> >
> >Howdy,
> >
> >We recently "found" an old set of beta reference sources with activity
> >units which I do not quite understand.  The date on the set is
> >November 1958.  The set contains:
> >
> >   Bi-210   1.07 X 10^-5 MC
> >
> >   C-14     14.3 X 10^-5 MC
> >
> >   Pa-234   1.00 X 10^-5 MC
> >
> >Any help identifying these units would be greatly appreciated.  Please
> >reply to me directly.
> >
> >Thanks,
> >
> >Tracy
> >
> >====================================================================
> >Tracy N. Tipping                                Work: (913) 532-2668
> >Laboratory Safety Officer                       FAX:  (913) 532-6806
> >James R. Macdonald Laboratory                   Home: (913) 539-1378
> >116 Cardwell Hall                               Amateur Radio: N0OEY
> >Kansas State University                         tipping@phys.ksu.edu
> >Manhattan, KS 66506-2604            http://www.phys.ksu.edu/~tipping
> >====================================================================
> >
> >
> >
There have been at least two posts giving the definition of mc as
millicuries--which is undoubtedly correct having used many of those
sources myself.

Why not help the person requesting the information with the conversion
factor that 1 curie is 3.7 E10 disintegrations per second or 
3.7 E10 Bq in todays units. That means 1 mc is 3.7 E7 Bq.

That should allow you to calculate the activity of the sources after
correcting for decay. The half lives are available on the GE Chart of
the Nuclides or in the Handbook of Chemistry and Physics.

Michael A. Kay, ScD, CHMM
mikekay@teleport.com