NAA

[Slaback@micf.nist.gov]

> -------------------------------------------------------------------------------
> I tried to respond directly to Sandy Perle, but
> our (collective) computers are not speaking.  So
> here is a few numbers, and caviats, from several sources....
> 
> Ti   4-100 ng
> V    .04-4 ng
> Cr   50-300 ng
> Fe   2- 10 ug
> Co   .3-1000 ng
> Cu   .1-2 ng
> 
> Typically these are based on intergerence free conditions.
> The tables I have come with the caviat of 'don't believe them'.
> Every sample matrix needs to be specifically evaluated to
> determine the sensitivity for any particular element.
> Some facilitities are better suited for particular types of
> analysis than others.  Variables of interest are
>   Cd ratio
>   Fast/thermal ratio
>   Fast spectrum availability
>   short half-life nuclides analysis capability
>   prompt gamma aqnalysis availability
> 
> Sandy's specific question related to metal alloys, but even that
> is not sufficiently specific for a good answer.  If there are
> dollars invovled many research reactor facilities will take on
> the task to do a specific assessment.  U of Missouri does a lot
> of this.  NIST does mostly inside work but does have several
> major outside users.  The USGS in Co, U of Mich, U of Va, and others
> also do this.
> 
> The NIST Cold Neutron Prompt Gamma analysis facility has detections
> limits (with the same caviats) of ....
>   H  0.1 ug
>   B  0.1 ng
>   Si 10 ug
>   Ti 0.2 ug
>   V  0.2 ug
>   Cr 0.5 ug
>   Mn 0.1 ug
>   Co  50 ng
>   Cu  0.5 ug
> 
> The CNPGAA technique uses an external neutron beam so
> that it has the advantage of being able to assess
> portions of a larger component without dismembering
> it for insertion into the reactor.
> 
> A little risk adds spice to life.
> slaback@MICF.NIST.gov
> 
> 
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> >From: Slaback@micf.nist.gov
> >To: Mul
> >Subject: Re: Neutron Activation Analysis - Alloys
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