XRF: X-Ray Fluorescence Spectroscopy

1. XRF:X-Ray
Fluorescence
Spectroscopy
Presented to: Prof. Neeraj Khare
Arvind
Research Scholar,
Entry no. : 2019PHZ8678
Taslim Khan
Research Scholar,
Entry no.: 2019TIZ8788

2. Outline
Historical Background
Introduction
Principle and Instrumentation
Strengths, Limitations and Applications
Summary and References

3. X-Ray Fluorescence Spectroscopy
Chemical theory
Type of emission radiation that
involves the secondary x-rays
Special x-rays are emitted from
larger elements when their
electrons makes transition from
higher energy states to lower
one’s

4. Historical Background
• X-rays were discovered in 1895 by W.C. Roentgen.
• However, X-rays become useful for analysis only after
Henry Moseley established the Famous Moseley law in
1913.
Moseley Law:  = 𝒂 𝒛 − 𝟏 𝟐
• Established a specific relationship between the
wavelength of a characteristic X-ray photon and the
atomic no. of the excited element
• The technique of exciting the sample became practical
in 1940’s and the first commercial XRF spectrometers
were produced in 1950.

5. XRF:X-Ray Fluorescence
X-ray beam
incidents on
sample
Specimen ionizes
Absorbed X-ray
beam ejects the
electron from the
inner shell
Higher energy shell
electron falls into
the vacated
position
Characteristic X-
rays emitted

6. Principle
The process of detecting and analysing the emitted X-rays is called X-Ray
Fluorescence Analysis.

7. Principle of XRF
• XRF works on methods of involving interactions between electron beam and x rays with samples.
• Made possible by the behavior of atoms when the interact with the radiation, when material are
excited with high energy, short wavelength, they can become ionized.
• If the energy sufficient to dislodge a inner shell electron, the atom becomes unstable and the
outer electron replaces the missing electron.
• When a electron comes from outer shell to inner shell emit the radiation .
• The emitted radiation is lower to primary incident X-rays and is termed as the fluorescent
radiation.
• The emitted photon is characteristic of a transition between specific electron orbitals of
particular element.
• The resulting fluorescent X-rays can used to detect the abundances of element that are present
in the sample.

8. XRF instrument and its block diagram
Fig 1. Apparatus of XRF
Fig 2. block diagram of XRF(WD)

9. Instrumentation:
• X-ray irradiates specimen
• Specimen emits characteristics X-ray or XRF
• Analyzing crystal rotates to accurately reflect each wavelength and
satisfy the Bragg’s n λ =2dsinθ
• Detector measures position and intensity of the XRF peaks
• XRF is diffracted by a crystal at different θ to separate X-ray I and
identify the element.

10. Components of the XRF Apparatus
• X-ray tube:
• Primary collimator
• Diffracting crystal
• Detector

11. Types of XRF spectrometers:

12. EDXRF WDXRF
• The entire polychromatic spectrum
from the sample is incident upon the
detector that is capable of registering
energy of each photon that strikes it
• The detectors electronics and data
system then build the X-ray spectrum
as a histogram, with number of counts
vs energy.
• Cheap , fast, and simple design
• Poor resolution, less sensitivity for the
low atomic number
• The instrument based on the principle
of the Bragg diffraction of the
collimated X-ray beam, the this case
the collimated beam from the sample
• A detector is angularly scanned
relative to the analyzing crystal,
registering the spectrum
• Expensive , slow, and complex design
• High resolution , sensitive for the low
atomic number

13. Results: 1. XRF of copper.
fig.3 the XRF of the the copper 29

14. 2. XRF of the silver

15. Compositional analysis of consecutive
elements of Zn, Ga, Ge, As and Se by XRF.

16. Analysis types
XRF analysis provides different types of data analysis:
Qualitative Analysis
Energy of the peaks leads to the identification
of the elements
Quantitative Analysis
Peak intensity provides the relevant or
absolute concentration of the elements

17. Sample Preparation
Optimal Sample Powder
•Should be grinded properly
•Minimises scattering effects due to particle size
•Entire sample is analysed and not surface only
Solid
Surface should be oriented in same manner
Polishing reduces the scattering effects
Flat samples are preferred for the analysis
Liquid
Care should be taken when analysing the evaporative samples

18. Strength and
Benefits
• Completely non destructive technique
• Accuracy
• Relative ease and low cost of sample preparation
• Stability and easy usage of X-ray spectrometers
• .Low testing cost
• On site testing possible
• No extra chemicals or acids required
• Possible with solid, liquid and powder

19. Limitations
• Inaccurate for low concentration elements (in ppb or ppt)
• Can not distinguish between different oxides
• Lighter elements can not be detected
• Can not distinguish variations among isotope of an element
• Radiation exposure concerns
• Overlapping emission peaks

20. Applications
• Metallurgy and chemical industry: quality control for raw
materials and final products
• Research & development: characterizing the specimens for
the research purposes
• Minerology: qualitative & quantitative inspection of
minerals, rocks and different soils
• In medicines: used for investigation and controlled mixture
of various elements in particular drugs
• Environmental studies: investigation of particulate matter
(particle pollution) for air quality
• Agriculture and food industry: detection of toxic metal
components in soils and agriculture products
.…many more in different industries

21. Conclusion
and Future of
XRF
In conclusion, XRF is a reliable and fast technique which can
be used for the accurate measurements of :
• The elementary composition of the sample
• Chemical analysis of the materials
TXRF: Total Reflection XRF - Performed at very low angle of
incidence (≤0.1°)
Improved detection limits for the thin film samples and for
every sample which can be deposited in thin film

22. References
Jenkins, Ron, X-Ray Fluorescence Spectrometry. 1988, 2nd ed.
New York: John Wiley& Sons. ISBN: 0-471-83675-3.
Hall, E.T. 1960. “X-Ray Fluorescent Analysis Applied to
Archaeology.” Archaeometry 3:29-37.
Joyce, R.A. 2011. “ Is there a future for XRF in Twenty-First
Century?” In Shackley 2011a, 193-202. New York: Springer.
Ferrero, J.L. et al. X-Ray Spectrometry, 2002, 31, 441-447.

23. Thank You!!
Arvind
Research Scholar
Entry no.: 2019PHZ8678
Taslim Khan
Research Scholar
Entry no.: 2019TIZ8788