Compound refractive lenses (CRLs) are an attractive alternative to Kirkpatrick-Baez mirrors or Fresnel zone plates as focusing elements. X-ray beamlines on Free Electron Lasers (FELs) and synchrotrons benefit from their robustness as they are less sensitive to external vibrations and surface contamination. Moreover, they preserve the beam trajectory, and their simple mechanical architecture renders them cost-effective.
An intrinsic problem of CRLs is their long focal length. This is due to the fact that the refractive index for X-rays is close to unity for all materials. This limitation is overcome by stacking multiple lenses together and by having a small radius of curvature (~50 µm). Both measures reduce the overall focal length, creating a compact focusing solution for incoming X-rays. Constant improvements in the manufacturing of thin lenses means that they can now be produced reliably and with a lower form error than ever before.
Traditionally, beryllium is the most used material for lenses withstanding energies up to 40 keV. The advantages of diamond lenses are the lack of scattering due to grain boundaries and superior thermal stability and conductivity. Furthermore, single crystal diamond lenses are applicable to nearly all energies of interest.
Advances in diamond laser ablation allow us to achieve high-level repeatability and low form errors, leading to complete freedom of operation. Moreover, the possibility to create multiple lenses in one diamond (e.g., 1D and 2D, or lenses of different sizes) offers cost-effective flexibility as it allows the user to switch between lenses with a simple translation of the CRL system.
In a ~20 minute meeting we will share the progress we have made in the processing of single crystal diamond CRLs and test results. The meeting will be followed by a live Q&A-session.
To accommodate viewing from any time zone we will hold the meeting twice:
June 15, 1.00 p.m. CDT (20.00 CET)
June 17, 11.00 CET (5.00 p.m CST)