HOPG Highly Oriented Pyrolytic Graphite
A highly pure and ordered form of synthetic graphite characterised by a low mosaic spread angle.
Applications
- Scanning tunneling microscopy-callibration and substrates
- Graphite Monochromator’s
- X-Ray diffraction
- Neutron scattering and diffraction
Physical Characteristics (at 300K)
| Spacing of Reflecting Planes (002): | 3.355 – 3.359 Å |
| Density: | 2.255 – 2.265 gem-3 |
| Thermal Conductivity Parallell (002): Perpendicular (002): |
16 – 20 Watt/cm K ca. 0.8 Watt/cm K |
| Thermal Expansion Parallell (002): Perpendicular (002): |
Slightly negative 20 x 10-6 / K |
| Electrical Resistivity Parallell (002): Perpendicular (002): |
3.5 – 4.5 x 10-5Ohm cm 0.15 – 0.25 Ohm cm |
1) Mosaic spread is the half maximum height peak width of the Cu-Ka
Products
HOPG plates are produced as flat, singly-bent and double-bent shapes. The
monochromators are classified according to mosaic spread.
| Grade | Mosaic Spread | Nominal thickness [mm]** | Minimum* size [mm] | Maximum* size [mm] |
|---|---|---|---|---|
| ZYA | 0.4° ± 0.1° | 2 | 12 x 12 | 50 x 50 |
| ZYB | 0.8° ± 0.2° | 2 | 12 x 12 | 50 x 75 |
| ZYD | 1.2° ± 0.2° | 2, 4 | 12 x 12 | 50 x 75 |
| ZYH | 3.5° ± 1.5° | 2, 4, 6, 8 | 12 x 12 | 75 x 75 |
* other sizes or specific mosaic spread on request
** Tolerance ± 0/-1 mm
Standard radii for singly-bent plates: 115, 225, 250, 510, 790, and 1.300 mm.
Standard size for bent monochromators (mm):
| 12 x 12, 20, 25, 40 | 20 x 20, 25, 40, 50 |
| 15 x 15, 25, 40, 50 | 25 x 25, 40, 50, 75 |