Date: Thu, 29 Aug 1996 08:15:15 -0500
Subject: Re: Strange peaks
From: vicenzi@phoenix.Princeton.EDU (Ed Vicenzi)

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Status: OR



I would like to reemphasize to comment below made by John Donovan

concerning the compositional dependence of the Fe La / Lb,and other 1st row

(4th period) transition metals for that matter. A recent extended abstract

by Armstrong appeared in Microbeam Analysis, Proceedings of the 29th annual

conference of the MAS '95,Breckenridge,CO.p 189-190 "Problems and

Opportunities in the use of L-lines of the 1st row Transition elements in

quantitative electron Microbeam Analysis."









>You should be aware that it is extremely important to understand that most

>of the variation in Fe La / Lb (704 and 718 eV respectively) ratios that

>you will be seeing, is almost entirely due to the presence of the Fe L-III

>absorption edge at 707 eV between the two lines.

>

>This means that any change in the Fe concentration of the sample, will

>change the relative absorption for the La/Lb lines. It is of course

>possible to correct the wavescan for absorption and that is exactly what

>must be done. However, from what I have heard, this correction removes most

>of any variation in the ratios that has been observed.



Ed Vicenzi tel (609) 258-1464 office

Princeton University tel (609) 258-1406 lab

Princeton Materials Inst. fax (609) 258-6878

70 Prospect Ave.

Princeton, N.J.

08540-5211 vicenzi@princeton.edu