NEUTRON DIFFRACTION METHOD and principles.pdf

It explains about the neutron diffraction method and its working principle

1. NEUTRON DIFFRACTION
METHOD
SUBMITTED BY,
MACDELIN BELSIYA.S
I – M.SC., CHEMISTRY

2. •Neutron diffraction is a technique used to study the
structure of materials at the atomic and molecular level.
• It involves directing a beam of neutrons at a sample and
measuring the scattering pattern produced as the neutrons
interact with the atomic nuclei in the sample.
•This scattering pattern provides information about the
positions of atoms within the sample, allowing scientists to
determine its atomic structure, crystallographic properties,
magnetic ordering, and other properties.
NEUTRON DIFFRACTION METHOD

3. •Neutron Diffraction is
particularly useful for
studying materials
with large unit cells,
complex structure,
and those containing
light elements such as
hydrogen.

4. • 

5. •Neutrons and electrons travelling at suitable velocities have
wavelengths of the order of 100-200 pm and thus undergo diffraction
by crystalline inorganic compounds.
•Neutron beams of the appropriate wavelength are generated by
‘moderating’ (slowing down) neutrons generated in nuclear reactors or
through a process known as spallation, in which neutrons are chipped
off the nuclei of heavy elements by accelerated beams of protons.
•The instrumentation used for collecting data and analyzing
single-crystal or powder neutron diffraction patterns is often similar to
that used for X-ray diffraction.

6. Fig. Instrumentation of neutron diffraction Technique

7. Neutron source:
Produces neutrons
Monochromator:
Sorts out discrete wavelength
Diffractometer:
Allows neutron to interact with sample
Detector:
Pick up neutrons scattered from the sample

8. WORKING:

•The technique requires a source of neutrons.
•Neutrons are usually produced in a nuclear reactor or
spallation source.
•The source of neutron passed through the monochromator,
and the monochromatized beam is made to fall on the
Sample.
•Filters are also used to select desired neutron wavelength.

9. •The sample is placed within a neutron beam and the
angles at which the neutrons are deflected or scattered
by the material are recorded to generate a ‘Diffraction
Pattern’ from which structural information can be
extracted.

•Sample requirement : Single crystal work is also
possible, but the crystals must be much larger than
those that are used in single-crystal X-ray
Crystallography.

10. The difference between the X-ray and neutron diffraction techniques
lies in the scattering process:

• X-rays are scattered by the electrons around the nucleus, whereas
neutrons are scattered by the nucleus.

•XRD uses X-rays, which are electromagnetic radiation. Neutron
diffraction uses neutron, which are subatomic particles.

•X-rays have a shorter wavelength and higher energy compared to
neutrons, allowing them to penetrate deeper into materials are
suitable for studying crystalline structures in solids. Neutrons, being
uncharged, penetrate deeply into materials and are particularly
useful for studying the bulk properties of materials, such as the
arrangement of atoms and magnetic structures.

11. •Neutron diffraction is more sensitive to light elements
like hydrogen, which have low X-ray scattering
factors. This makes neutron diffraction particularly
useful for studying materials containing hydrogen or
other light elements.

•X-ray diffraction is widely used in the study of
crystalline materials, including determining crystal
structures, identifying phases, and analyzing crystal
defects.

12. •Neutron diffraction is especially valuable for
investigating magnetic structures, studying
materials containing hydrogen, probing
materials at extreme conditions(such as high
pressure or temperature), and examining
biological systems.

13. THANK
YOU