RE: Help!

["Falo, Gerald A Dr HMJF" <Jerry.Falo@us.army.mil>]

Jay,

 

I don't know if there is an *easy* way or not. What I've done is use

qualitative NaI spectroscopy. I would collect a spectrum with an instrument

like the Berkeley Nucleonics SAM 935 or Exploranium of the material of

interest either in situ or of a sample and compare that spectrum with

spectra from NORM and with an appropriate background spectrum. Usually, I

use a thoruim source or radium source - some times a piece of Fiestaware

will work. More often than not, photopeaks from the progeny of the U-Th

series are very apparent in the sample that are clearly enhanced over

background. Remember, these are only qualitative measurements it would

require more rigor to quantify the amount of NORM in a given sample.

 

You may also want to look at NUREG1507 and NUREG1501 for a discussion of

background concentrations of NORM and include a discussion in whatever

report you write.

 

I hope this helps.

 

Jerry

 

The discussion of specific manufacturers' instruments does not imply an

endorsement or condemnation by me or my employer.

 

The statements and opinions expressed herein are my responsibility; no one

else (certainly not my employer) is responsible, but I still reserve the

right to make mistakes. 

 

Check core temperature: yes./no? Yes! - Homer Simpson

 

 

Gerald A. Falo, Ph.D., CHP

Henry M. Jackson Foundation for the Advancement of Military Medicine

U.S. Army Center for Health Promotion and Preventive Medicine

 <mailto:gerald.falo@apg.amedd.army.mil> gerald.falo@apg.amedd.army.mil

jerry.falo@us.army.mil

410-436-4852

 



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

From: Jay Beckel [mailto:jbeckel@ameslab.gov] 

Sent: Tuesday, March 09, 2004 2:03 PM

To: 'Radsafe (E-mail)'

Subject: Help!





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