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XRF background:
 X-ray fluorescence (XRF) is a technique used to identify elements in a sample. It uses an x-ray source of tipycally 1 to 6 KeV. In XRF, a sample is radiated with x-rays and electrons are ejected from the sample leaving a hole behind. Electrons in higher orbitals then fall to occupy the empty spaces left by the ejected electrons; and when they fall, they emit energy in the form of photons. The energy emitted is equal to the difference in energy between the two energy levels involved. This radiated energy is used as a finger print to indentify the elements in a sample



XRF report:

In this lab, three regions of one piece of ceramic were tested with XRF to determine the elemental composition of the ceramic piece.  The three regions of the specimen corresponding to a light region (17153A), dark region (17153A-2) and another dark region with a bright spot (17153A-3) were analyzed using a X-MET 3000TX XRF analyzer, which is a portable x-ray fluorescence analyzer. A picture depicting the three areas of the specimen is shown in figure 1. After data readings were collected, data was analyzed with the PyMca software.



Figure 1. Picture showing the three areas of the specimen used to determine elemental composition


The first step made to analyze the data collected with XRF analyzer was to calibrate the data as follows:Once the data was loaded in PyMca, S# 2.1 was selected. In the calibration menu, "Internal (from source or PyMCA)" was selected and then calibrate > compute. Then the Ag peak was identified as the graph shown below (figure 2). In the element menu, Ag(47) was selected and in the line menu KL3(0.54112). This completes the calibration process.

Figure 2. Calibration of data in PyMca

After calibration was performed, a spectrum for each region of the sample was obtained. Figure 3, 4 and 5 show the spectra and fit of the data made by the software to determine the elemental composition of the sample.
  

Figure 3 Spectrum obtained for the light region (17153A).




Figure 4 Spectrum obtained for the dark region (17153A-2).





 Figure 5 Spectrum obtained for the dark region with a bright spot (17153A-3).




 A list of the elements with their respective mass fraction for each of the regions analyzed is shown in tables 1, 2 and 3.
 

Table 1. 17153A

 

 

Element

Mass fraction

Fe

0.001562

Zn

6.13E-06

Rb

3.33E-06

Sr

1.30E-05

Zr

8.28E-06

Nb

1.44E-06

Pd

5.12E-06

Ag

2.04E-07

Hf

1.22E-06

Au

8.88E-06

Fm

1.66E-04

   

| Table 2. 17153A-2
|

 

 

Element

Mass fraction

Fe

0.001472

Zn

4.26E-06

Rb

2.64E-06

Sr

1.09E-05

Zr

6.02E-06

Nb

1.22E-06

Pd

4.29E-06

Ag

2.86E-07

Hf

8.75E-07

Au

8.32E-06

Fm

1.40E-04



Table 3. 17153A-3

 

 

Element

Mass fraction

Fe

0.001503

Zn

4.69E-06

Rb

2.99E-06

Sr

1.24E-05

Zr

7.52E-06

Nb

1.50E-06

Pd

4.82E-06

Ag

2.13E-08

Hf

1.02E-06

Au

8.75E-06

Fm

1.52E-04





Also, plots of the elements with highest mass concentration were made in order to compare the areas of the sample that were analyzed. These plots are shown in figure 6.



 

 
 

 Figure 6 Shows mass fraction plots for some of the elements found in the ceramic. 

Team members

 
Guillermo Delgado (left) and Brandon Aguirre (right) 


 

References:

George M. Crankovic, ASM handbook Materials Characterization Volume 10

http://en.wikipedia.org/wiki/X-ray_fluorescence

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