Low energy gamma spectra analysis

[Wes Van Pelt <VanPeltW@idt.net>]

Hi Radsafers,

I copy an abstract below which may be of interest.  Seems like a more
sensitive method of detecting things like Pu and U inside shielding such as
drums.

Regards,
Wes
--
Wesley R. Van Pelt, Ph.D., CIH, CHP                KF2LG
President, Van Pelt Associates, Inc.
Consulting in radiological health and safety.
mailto:VanPeltW@IDT.net         http://shell.idt.net/~vanpeltw/index.html


 Title:        Innovative method for extracting isotopic information from
               low-resolution gamma spectra
 Document ID:  19990045971
 Report #:     DE99-000666, LA-UR-98-1899
 Sales Agency: Department of Energy Information Bridge Microfiche
               No Copyright
 Authors:      Miko, D.
               Estep, R. J.
               Rawool-Sullivan, M. W.
 Published:    19981231
 Source:       Los Alamos National Lab. (NM United States)
 Pages:        5
 Contract #:   None
 Abstract:     A method is described for the extraction of isotopic
               information from attenuated gamma ray spectra using the
               gross-count material basis set (GC-MBS) model. This method
               solves for the isotopic composition of an unknown mixture
               of isotopes attenuated through an absorber of unknown
               material. For binary isotopic combinations the problem is
               nonlinear in only one variable and is easily solved using
               standard line optimization techniques. Results are
               presented for NaI spectrum analyses of various binary
               combinations of enriched uranium, depleted uranium, low
               burnup Pu, Cs-137, and Ba-133 attenuated through a suite of
               absorbers ranging in Z from polyethylene through lead. The
               GC-MBS method results are compared to those computed using
               ordinary response function fitting and with a simple net
               peak area method. The GC-MBS method was found to be
               significantly more accurate than the other methods over the
               range of absorbers and isotopic blends studied.

************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html