#weekendusers Nanofocusing at high energies

09-09-2016

This weekend, Markus Osterhoff, Christian Eberl and Jakob Soltau, three young scientists from the University of Göttingen, in Germany, are testing a new nanofocus optics device for microscopy experiments on the high energy beamline ID31.

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X-ray microscopy started in the 1970s in the soft X-ray regime, and it was only after coherent sources appeared, new fabrication techniques emerged, and computer power increased that the technique could be used in hard X-rays (ranging up to 24keV). Today it is routinely used in material science research as well as biological research.

At present it is impossible to focus X-rays to less than 20 nanometres in the high energy ranges (30-90keV). In the last five years, the team has worked on the design and development of a so-called Multilayer Zone Plate (MZP) optics. This device has been fabricated using Pulsed Laser Deposition and it offers the necessary optical thickness needed to focus down to a few nanometres. “We are expecting to go down to 20 nanometres, but we are hopeful that we’ll reach 10 nanometres”, explains Christian Eberl inside the huge experimental hutch of the beamline.

They have already tested the MZP at PETRA III in Germany at energies up to 18keV, but this weekend, they will test the device for the first time at the energy of 60keV, using silver crystal droplets and semiconductor nano wires as samples. “Today, you can do high resolution microscopy and high energy microscopy separately. What we want to do is merge them”, says Eberl.

MZP.JPG

From left to right: Markus Osterhoff, Jakob Soltau and Christian Eberl, during the set up of the MZP optics.

Since the experiment is technically challenging, the team compares different imaging methodologies, for example x-ray transmission microscopy for real-space imaging, scanning nano-SAXS and nano-WAXS to resolve fine silver droplets buried within zirconium oxide, fluorescence mapping and possibly scanning x-ray reflectivity measurements. In order to tackle challenges like stringent alignment requirements and to benchmark this wide array of imaging techniques, the team has been granted almost a week of beamtime at the ESRF. "We feel very fortunate to be given all this time, and we will make the most of it. Even if this means we can't really enjoy the summery weekend, it is really worth it", explains Markus Osterhoff.

Text by Montserrat Capellas Espuny