Re: Help! (Basement radiation surveys)

["Frank Helk" <frank.helk@nis-hanau.de>]

Hi Mark,



>It seems you should be using spectroscopy rather than gross counting. 

>If you can decide on your regions of interest for your "contaminant" 

>versus NORM, then you might have an easy answer.  

>Otherwise, to model it, you would need to know the thickness of the 

>concrete floors, walls and ceilings and what the self-shielding effects 

>would be - which is dependent on the gamma energy. It won't be simple; 

>you'll need someone who does professional shielding calculations.  



As Jay mentioned, there is a significant diffrenece between similar rooms that are above ground level and room in the basement. I've some experience with 

that, esp. with gross gamma measurements (plastic scintillator) and I would blame the short lived decay products of Radon for that.



As I've lined out to Jay, she should make some experiment with measuring, ventilating the room excessive and the measuring again immediate after venting.



Most of the doserate from Radon decay products binds on airborne particles and is therefore airborne or lying on horizontal surfaces. The doserate from 

natural activity in the building structure is mostly insignificat, due to the fact that most of the gamma radiation is of low energy and therefore easily shielded by 

the structure itself.



BTW: If the doserate comes from the building structure, it would be the same in the rooms above ground level, given that almost the same conctere was 

used.



Best regards





	Frank Helk





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