HOPG (ZYA Grade)

Highly Oriented Pyrolytic Graphite (HOPG) and are forms of high purity Pyrolytic Graphite annealed under pressure at temperatures about 3000ºC. Its main physical characteristics (at 20ºC) are summarized in the following Table.

interlayer distance (002)

3.354-3.358 Å


2.24-2.25 g/cm3

thermal conductivity parallel (002)
thermal conductivity perpendicular (002)

1700+/-100 W/(m·K)
8+/-1 W/(m·K)

thermal expansion parallel (002)
thermal expansion perpendicular (002)

-1x10-6 K-1
20x10-6 K-1

electrical conductivity parallel (002)
electrical conductivity perpendicular (002)

2.1+/-0.1x106 [(W·m)-1]
5x102 [(


> 99.99 %

HOPG crystals are used as monochromators and focusing optics for x-ray beams. Some typical parameters of the HOPG optics are shown in the following Table.

Energy range

2-120 keV

Reflection coefficient


Integral reflectivity

up to 0.01 rad

Rocking curve width


Solid angle of capture

up to 0.1 sr

Focal spot size

100-500 µm

HOPG-based monochromators and focusing optics can be also used for neutron beams.



Mosaic spread

Nominal thickness

Minimum size

Maximum size


0.4+/-0.1 degrees

2 (-1) mm

10 mm x 10 mm

30 mm x 20 mm

Other sizes or specific mosaic spreads can be possible on request!