Lect13_notes

25 from x ray creation to quantitative results there

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: nd the underlying principles (physics) behind the data-analysis – such that you are a sophisticated analyst rather than a mere user (and slave to canned systems). The data reduction software will often present procedure choices; by understanding the physics, one can make beneficial choices. CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13 ! 25 From X-Ray Creation to Quantitative Results! •  There are two parts to the problem –  What happens to the x-ray signal within the sample before exiting in the direction of the detector –  What happens to the signal within the detector before a count is added to a channel in the multichannel analyzer (MCA) CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13 ! 26 Problem is Worked Backwards! •  The data is the spectrum •  For a quantitative analysis –  need to work backwards to calculate what x-ray intensities needed to have been generated within the sample –  Detector artifacts need to be identified –  Corrections for in-sample events need to be accounted for - ZAF corrections CBEMS 164 – XRD, SEM & Microanalysis: Lecture 13 ! 27 Issues with Quantitation! •  Electron beam impinges on sample –  Interacts with sample within an interaction volume –  Energy loss in incident beam during multiple interaction events result in generation of characteristic and background x-radiation •  X-rays leave point of creation in all directions –  Intensity generated is f(Z) –  Some...
View Full Document

This note was uploaded on 01/16/2014 for the course CBEMS 164 taught by Professor Porter,j during the Fall '08 term at UC Irvine.

Ask a homework question - tutors are online