Three-day exchange at User Meeting
From December 12 to 14, more than 400 users of HZB's BER II and BESSY II large-scale equipment met up to discuss the current state of technology and exchange their views on pressing scientific issues. Two of the highlights were Science Day on December 13 and Neutron Day on December 14, both held at the Bunsensaal in Berlin-Adlershof. Both days, the focus was on instrumentation. Participants were able to learn about new technologies and advances in large-scale equipment instrumentation. Science Day featured the many scientific achievements that have been made thanks to BESSY II and BER II.
Holger Dau of the Free University Berlin delivered the keynote lecture titled "X-ray spectroscopy in solar-fuels research - from biology to inorganic catalysts." EMPA Zurich's Andreas Züttel gave the public lecture titled "What we learn from history to master the future energy challenge." The two lectures impressively highlighted the tremendous potential of large-scale equipment in energy research.
Science Day awards
On December 13, two awards were given out by the Helmholtz Centre Berlin Circle of Friends. Recipients of this year's 4000 Euro Synchrotron Radiation Innovation Award included DESY's and European X-FEL's Gianluca Geloni, Vitali Kocharyan, and Evgeni Saldin as well as Paul Emma of the Lawrence Berkeley National Laboratory. The four physicists were being recognized for their development of a "self-seeding" protocol that significantly improves free-electron laser technology.
The Ernst-Eckhard-Koch Award for excellence in doctoral-level research in the amount of 2500 Euros went to up-and-coming physicist Dr. Daniil Evtushinsky of the Leibniz Institute for Solid Body and Materials Research in recognition of his work on band-structured and fermi areas of a new class of two-dimensional, high-temperature superconductors.
The HZB User Committee's Best Poster Award went to Christian Caspers of the Jülich Research Centre for the skillful presentation of his work on "Magnetic Oxides EuO Thin Films on Surface Passivated Silicon for Silicon Spintronics."
240 posters, 51 vendors
During the poster session in BESSY experimental hall, a total of 240 posters documented the work done by both HZB and external researchers using the HZB research facilities, with topics ranging from the life sciences and basic physics research to applied research on industrial materials. In addition, five satellite symposia sought to answer pertinent questions on neutron spectroscopy, crystallography, and related topics.
As in previous years, the user meeting featured a well-attended industry exhibit with 51 vendors of synchrotron spectroscopy and neutron diffraction experimental equipment showcasing a broad range of state-of-the-art products. Thanks to the vendors' generous financial support, the lavish "Berlin Buffet" on Thursday night, which offered yet another chance for conversation and networking, attracted many visitors. The organizers would like to thank Adlerhof con.vent, WISTA Management GmbH's event planners, for organizing the industry exhibit.
- Disorder creates new properties in compound semiconductorsAn international research team has demonstrated that the intrinsic disorder of the compound semiconductor CuInSnS₄ can be exploited to influence its optical properties. While the atomic vibrations also sense the local disorder, their response is averaged over many different local environments and therefore appear isotropic, as expected for a cubic crystal. In contrast, the optical excitations, known as excitons, are much more sensitive to the local arrangement of atoms. Surprisingly, they show a direction-dependent optical response even though the average crystal structure is cubic. These findings shed new light on the relationship between disorder and material properties, opening up new options for targeted 'disorder engineering' in optoelectronic and photocatalytic devices.
- Superconducting TES array X-ray spectrometer goes into operation at BESSY IIEurope's first and only TES-spectrometer at a synchrotron source is now in operation at BESSY II, developed within a collaboration between the HZB, the MPI-CEC (Mühlheim-an-der-Ruhr, Germany) and the NIST (Boulder CO, USA). The photon detection efficiency of the new instrument exceeds that of wavelength-dispersive X-ray emission spectrometers by a factor of 100 to 1000. It will be used to investigate the electronic properties of atomically thin layers, nanostructures and highly diluted atomic and molecular samples. The team is looking forward to receiving exciting research proposals from the user community.
- Magnon momentum microscopy: A new window into nanoscale spin-wavesAn international team lead by the Max Born Institute has developed a new type of momentum microscopy to image magnons — the quanta of collectively excited spins — directly in two-dimensional reciprocal space using soft X-rays. Measurements have taken place at BESSY II and PETRA III, first author ist the HZB physicist Steffen Wittrock. Owing to its remarkable sensitivity, simplicity, and access to nanometer-scale wavelengths, this novel technique establishes a powerful and versatile platform for exploring nonlinear magnon interactions, which are promising for future computing schemes.