Help!

[Jay Beckel <jbeckel@ameslab.gov>]

We are working on surveying a basement area and part of the surveys include

gross gamma counting w/ NaI detectors.  We've done fairly extensive

measurements with handheld probes and smears to detect fixed alpha, beta or

removable alpha, beta, gamma, but wanted to provide a little extra assurance

that we didn't miss something.  Our problem lies in building materials and

background in certain areas.  Part of the basement is open top (no ceiling),

part is concrete slab ceiling.  Secondly, two areas of the basement are

similar to dead end hallways and this is where the concrete ceilings are

also.  Naturally, the gamma counts are going to increase as we enter the

'hallway' areas due to increased NORM.  However, I'm looking for a somewhat

simple way to quantify this increase and reassure someone who is looking at

my data that it is NOT contamination.  Does anyone know of any modeling I

can apply to this situation?  Anyone have similar experiences?  We have

looked all over the site for similar building configurations and have come

up empty handed at this time.  If you have any advice, please reply directly

to me, or you may reply to the list if you feel there may be some other poor

souls out there like me:)

 

Thanks,

Jay