Re: Neutron Activation Analysis - Alloys

[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