Diamond X-Ray Windows
Diamond exhibits a bunch of unique properties such as extreme hardness, high thermal conductivity and chemical inertness. In terms of X-ray windows another property of diamond is of crucial importance: diamond consists of carbon i.e. diamond is a low Z material which is transparent to X-rays.
In synchrotron accelerators the white-beam X-ray window is subjected to a high thermal load due to the absorption of low energy X-rays. In this context the unique thermal conductivity of diamond is of central importance. By appropriate edge cooling techniques CVD diamond window can handle much higher power levels as compared e.g. to beryllium. In addition CVD diamond is a non-toxic material facilitating the safety requirements during operation.
High transmission coefficients even at low X-ray energies can be achieved by using thin diamond membranes mounted on circular silicon support disks. The thickness of these membranes can be as low as 1 µm. The free aperture depends on the maximum pressure difference the window must be able to handle.
|Size||2-20 mm free aperture(typical: 4-10 mm)|
|Design||Efficient water cooling jacket|
bakeable to up to 250°C
|Thickness||Thickness 20 – 300 µm (UHV compatible)
or 1-50 µm for O-ring sealing
|Material||CVD Diamond, "optical grade"|
|Surface||Polished, surface roughness < 10 nm rms|
|Shape||Circular or oval free aperture|