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RE:

A.G. Geerdink and Franz



FYI, if thorium is there (and I think it is) it will be Th-232 and Th-228 in

equilibrium with all the progeny in the thorium decay chain. The longest

lived is Ra-228 (6.7 years) and if the trorom was seperated 25 years ago it

will be almost at equilibrium.



I also agree with Franz that doses "are orders of magnitude below any dose

rates you should be concerned about", onless you spend a lot of time around

a wash bowl in an office or another similar situation.



John



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-----Original Message-----

From: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]On Behalf Of Franz Schoenhofer

Sent: October 17, 2003 3:46 PM

To: vw 181; radsafe@list.vanderbilt.edu

Subject: AW:





-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von vw 181

Gesendet: Freitag, 17. Oktober 2003 14:31

An: radsafe@list.vanderbilt.edu

Betreff:





Dear Listers,



If you hold a radiation monitor near a porcelain wash basin or toilet bowl,

you can measure a rise in radiation. Some say this radiation comes from K

40, others told me this radiation is Th 232.

Does anybody know which isotope is found in porcelain?

Which isotope could be measured at the surface of the material?



A.G. Geerdink



------------------------------------



Dear Mr Geerdink,



My sanitary porcelain does not show any rise in dose rate. You cannot define

"radiation of porcelain", it depends on the source of the compounds your

porcelain was made of. Some of the "ingredients" may contain uranium and its

daughters, some others may contain thorium and its daugthers, but

practically no material will not contain K-40, which will contribute to the

dose rate, depending of course on its concentration.



Uranium glazes have to my knowledge not been applied to sanitary porcelain,

but to tiles. They can be easily identified by their unique and bright red

colour. Nevertheless the glaze will contain certain minerals which have been

put forward by another RADSAFEr as a possible source of thorium.



You do not report the dose rates you measured, though I am convinced that

they are orders of magnitude below any dose rates you should be concerned

about, especially when considering the short time you spend in front or

above sanitary porcelain.



Best regards,



Franz







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