X-ray Diffraction from Graphite in the Energy Range 2 to 8 keV

1973 ◽  
Vol 27 (6) ◽  
pp. 454-456 ◽  
Author(s):  
H. L. Kestenbaum
Keyword(s):  
Energy Range ◽  
Energy Dependence ◽  
Pyrolytic Graphite ◽  
Highly Oriented Pyrolytic Graphite ◽  
X Ray Diffraction ◽  
Graphite Crystal ◽  
X Ray

We report x-ray diffraction measurements from highly oriented pyrolytic graphite over the energy range 2 to 8 keV. The measured reflectivity exhibits an energy dependence which closely follows that predicted for an ideally imperfect graphite crystal, although the reflectivity itself is a factor of 1.5 less than the calculated value.

An energy-dispersive X-ray diffraction study of mean-square atom displacements in highly oriented pyrolytic graphite

1986 ◽  
Vol 19 (3) ◽  
pp. 200-201 ◽  
Author(s):  
T. H. Metzger
Keyword(s):  
Pyrolytic Graphite ◽  
Energy Dispersive ◽  
Mean Square ◽  
Highly Oriented Pyrolytic Graphite ◽  
X Ray Diffraction ◽  
Thermal Diffuse Scattering ◽  
X Ray ◽  
Integrated Intensity ◽  
The Mean ◽  
Thermal Diffuse

The measurement of the mean-square thermal displacement 〈u 2〉 of carbon atoms in highly oriented pyrolytic graphite (HOPG) in the hexagonal c direction is reported. Energy-dispersive X-ray diffraction (EDXD) has been used to study the integrated intensity of all Bragg reflections 004 through 0′0′14 as a function of temperature. It is demonstrated that the correction of the Bragg intensities due to thermal diffuse scattering contributions is very important for HOPG, when EDXD is used. The Debye temperature ΘD = 554 (30) K is obtained.

Investigations on the structural disordering of neutron-irradiated highly oriented pyrolytic graphite by X-ray diffraction and electron microscopy

2005 ◽  
Vol 38 (2) ◽  
pp. 361-367 ◽  
Author(s):  
Anjana Asthana ◽  
Yoshio Matsui ◽  
Makoto Yasuda ◽  
Koji Kimoto ◽  
Tadao Iwata ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Neutron Irradiation ◽  
Lattice Spacing ◽  
Pyrolytic Graphite ◽  
Lattice Parameter ◽  
Irradiation Damage ◽  
Highly Oriented Pyrolytic Graphite ◽  
X Ray Diffraction ◽  
Static Displacement ◽  
X Ray

Light and heavy neutron-irradiation damage of highly oriented pyrolytic graphite (HOPG) crystals was examined by means of X-ray diffraction and high-resolution high-voltage transmission electron microscopy (TEM). From the X-ray data analysis, it was found that there is an average increase of about 3% in thec-axis lattice parameter of the unit cell of graphite for lightly neutron-irradiated HOPG. However, thec-axis lattice parameter could not be estimated from the HOPG sample having the highest dose of neutron irradiation under the present investigation, because the X-ray profile was highly asymmetrical. This increase in thec-axis lattice parameter is attributed to lattice expansion due to the static displacement of atoms after neutron irradiation. Local structure analysis by TEM shows that the 0002 lattice spacing for the above-mentioned HOPG samples has been increased by up to 10% as a result of the neutron irradiation. This increase inc-axis lattice spacing can be ascribed to the fragmentation of the crystal lattice into nanocrystallites, breaking and bending of the 0002 straight lattice fringes, appearance of dislocation loops, and extra interstitial planes within the fragmented nanocrystallites. All these changes are a result of the static displacement of atoms after neutron irradiation.

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