FISCHER FISCHERSCOPE X-RAY 4000 Series, Operator'S Manual

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42 FISCHERSCOPE
®
X-RAY
User Interface of the WinFTM Software The Spectrum Window
Procedure
1. Select in the Spectrum window View > Elements .
You can display the extended elements list. To do so, select in the Spectrum window
View > Full element list .
2. Click into the spectrum window, keep the mouse button pressed and move the cursor
to a peak of the spectrum.
A list of radiation components of one or more elements is displayed on the left next to
the spectrum window.
3. Click in the elements list on one radiation component.
The energy lines associated with this element appear as colored lines in the spectrum
window. You can compare the peaks of the measured spectrum with the superimposed
lines to identify the elements that comprises the sample.
4. Repeat steps 2 to 3 to determine further elements of the sample.
You can change the colors of the spectra and the energy lines. To do so, select in the
spectrum window
View > Color… .
6.8.7 Energy
The energy distribution contained in the spectrum informs about the composition of the
sample, because each occurring element of the sample reflects the qualitative composi-
tion through its peak position (at the horizontal position specified for this element).
The higher the X-ray fluorescence energy of an element, the further to the right the corre-
sponding line will be in the spectrum.
According to Moseley’s Law, the energy increases as the atomic number of the respective
element increases, i.e., the lines of the “heavier” elements (those with a higher atomic
number) are further to the right in the spectrum.
The energy is measured in keV = kilo electron volts. 1 eV is the energy that an electron
gains as it moves through a field with a potential difference of 1 V.
6.8.8 Intensity
The intensity of a radiation is the amount of radiation that strikes a certain unit of area in
a specified time period.
In X-ray spectroscopy, the intensity of the radiation is measured as the count rate in
counts per second (cps).
Each peak in the spectrum corresponds to a relative maximum referenced to its
surrounding. This maximum correlates to the amount of radiating atoms of the corre-
sponding element.
The higher the peak, the more atoms of the respective element are present in the sample,
i.e., the higher the concentration of the respective element in the sample.
Thus, the intensity of the spectral line is a measure for the quantitative composition of the
sample.