[meteorite-list] Iridium (+ Osmium ? + Technetium ?) measuring and testing

From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Sun, 15 Mar 2009 22:11:32 -0700 (PDT)
Message-ID: <4463.93930.qm_at_web55205.mail.re4.yahoo.com>

Hello Darren The original post never made it to my mail box. To the original posters questions about metal detectors:

One of the points to be made is that a metal detector only detects free metal not elements. It is a "field test" and searching for specific elements is a "lab test'
 
 As they say on the American TV Game Show-- Family Feud --"gudanzer"! my I say--"gudlinks".
Elton

--- On Sun, 3/15/09, Darren Garrison <cynapse at charter.net> wrote:
 
> >A- measuring on the field/ meteorite finding/ first testing:
> >I read often that finders/hunters use magnets. What
> about a metal detector measuring Iridium ?
> >or is Iridium detection too close to other elements, or too small in content to be singled out ? and what about Osmium ? or Technetium ?
> >
> >B- testing
> >How is Iridium (or Osmium, or Technetium) analysed and
> tested ? Is there any non-invasive way to test one or more of
> them, to keep the meteorite "as is" ?
>
> I was sitting here trying my best to remember the name of a
> type of measurement used to find very small amounts of atoms in materials (as is often the case) it
> wasn't coming to me. Fortunately I remembered it being
> described in a book by Walter Alverez called T. rex and the Crater of Doom,searched down my copy and was reminded that it is "neutron activation analysis". Good book on the
> detective work behind the discovery of the iridium (and
> other rare element) concentrations at the K/T boundary. You should try to get your hands on a copy. You can preview big chunks of it on Google Books:
> http://books.google.com/books?id=kkHhl67ixwEC&printsec=frontcover&dq=rex+and+the+crater+of+doom#PPA66,M1
>
> Use the right-hand search window to search for
> "neutron activation analysis" in
> the book.
>
> http://en.wikipedia.org/wiki/Neutron_activation_analysis
>
> As for technetium, I wouldn't hold my breath about
> finding much of it. Very
> short half life, both in human terms for some isotopes
> (hours to days) and in cosmic terms (at most a few million years, a blink of the eye in the age of a
> meteorite). The amount (from some googling) produced
> naturally by uranium decay and neutron absorbtion in molybdenum seems to be vanishingly small. Doesn't
> look to be much to be a mesurable amount to picked up from
> the solar wind (though this article is pretty old)
> http://www.new.dli.ernet.in/rawdataupload/upload/insa/INSA_1/20005aca_407.pdf
>
> Here's an article touching on the decay products of
> technetium in meteorites:
>
> http://wwwsoc.nii.ac.jp/jnrs/paper/JN63/jn6325.pdf
>
> and another:
>
> http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1877.pdf
Received on Mon 16 Mar 2009 01:11:32 AM PDT